JP6191404B2 - Sludge activity measuring apparatus and sludge activity measuring method - Google Patents

Description

  The present invention relates to an activated sludge treatment of a liquid containing a substrate that is decomposed by activated sludge, such as industrial wastewater and industrial wastewater, and oxygen by living organisms when treating a liquid containing a substrate that is decomposed by activated sludge. The present invention relates to an apparatus for measuring sludge activity to determine sludge activity.

  In recent years, water quality regulations in closed water areas have been strengthening, and countermeasures for sewerage, industrial wastewater, and factory wastewater are urgently needed. In order to comply with the water quality regulation value, it is necessary to grasp which component can be processed to what extent and to what extent. Until now, in the sewerage field, sewage treatment methods have been taken by biological treatment processes such as activated sludge process. Activated sludge is a collective term for organisms that metabolize and decompose various components in wastewater, and the quality of wastewater can be purified by its metabolism and decomposition.

  In order to understand the degree of activity of how metabolized and decomposed actively, the activated sludge and the liquid containing the substrate decomposed by the activated sludge are reacted in the laboratory, and the sample is sampled and analyzed sequentially. It is possible to grasp the change of the water quality. In particular, the single tank type oxygen consumption rate test (Oxygen Uptake Rate; OUR test) is a method of monitoring oxygen consumption by living organisms when treating a liquid containing a substrate that is degraded by activated sludge. After contacting the substrate decomposed by sludge in the reaction vessel, the dissolved oxygen concentration in the reaction vessel is measured with a dissolved oxygen electrode. As the reaction progresses, the dissolved oxygen concentration decreases, so when the air drops below a certain value, the aerated oxygen concentration rises, and when it exceeds a certain value, the aeration stops and then the dissolved oxygen concentration again. Decreases. By considering this decrease in dissolved oxygen concentration as the metabolism / decomposition of organisms, it becomes possible to grasp the metabolism / decomposition in detail (Non-patent Document 1). This is used in the evaluation of wastewater toxicity in Patent Document 1, and it is also possible to determine how much the metabolism and decomposition of the substrate by activated sludge is inhibited by the toxic substance. Moreover, since the dissolved oxygen consumption can be easily measured with the dissolved oxygen electrode, metabolism / decomposition can be grasped relatively quickly.

  Further, Non-Patent Document 1 also describes a two-tank oxygen consumption rate test shown in FIG. The configuration of the two-tank oxygen consumption measuring device 21 is that the aeration container 25 in the first tank contains a liquid 22 containing a substrate that is decomposed by activated sludge and an activated sludge 23, and is continuously aerated with the aeration device 24. The dissolved oxygen concentration measuring tank 29 in the second tank is hermetically sealed with a sealing plug 33, but the inside can be stirred with a stirrer 31 of a stirrer 30 and a dissolved oxygen electrode 32 is inserted therein. Then, when the mixture of the liquid 22 containing the substrate decomposed by the activated sludge in the first tank aeration container 25 and the activated sludge 23 is fed to the second dissolved oxygen concentration measuring tank 29 by the liquid feeding means 28, The second dissolved oxygen concentration measuring tank 29 is sealed and returned to the first aeration container 25 by the amount of the introduced sample. When the liquid feeding is stopped, the dissolved oxygen concentration 26 measured by the dissolved oxygen concentration meter 27 using the dissolved oxygen electrode 32 decreases due to the metabolism and decomposition of the substrate by the activated sludge in the dissolved oxygen concentration measuring tank 29. Thereafter, when the concentration becomes lower than a certain dissolved oxygen concentration, the liquid feeding means 28 operates again, and the mixture of the substrate and the activated sludge in which the dissolved oxygen concentration in the first tank aeration container 25 is saturated is dissolved oxygen in the second tank. When the concentration measuring layer 29 is replaced and the liquid feeding means 28 is stopped, the dissolved oxygen concentration decreases due to metabolism and decomposition.

  However, in the oxygen consumption rate test, it is necessary to analyze the data of dissolved oxygen consumption, specifically to obtain the oxygen consumption rate by obtaining the slope, but how to take the slope for which data range This needs to be performed by a skilled engineer using an arithmetic unit. For this reason, it is difficult to perform all oxygen consumption rate tests on-site or on-site. After taking the sample and performing the oxygen consumption rate test in the test room, the analysis is performed with a computing device, or the oxygen consumption rate test is performed on site. After performing the above, there were many cases where the experimental data was taken home and analyzed with an arithmetic unit.

JP 2010-271192 A

Shun Miso, activated sludge model, Japan, Environmental Newspaper Co., Ltd., January 31, 2005

  As described above, in the oxygen consumption test, it is possible to grasp the metabolism and decomposition of organisms in the treatment of a liquid containing a substrate that is decomposed by activated sludge, but there are various limitations as described below.

  As described above, in order to obtain the oxygen consumption rate, it is necessary to obtain the slope from the dissolved oxygen consumption data. The calculation of the slope requires data that the dissolved oxygen concentration continuously decreases during a certain time, but in what range the certain time is set and / or the dissolved oxygen concentration continuously decreases It is necessary to set which range of variation is allowed in the data. If the setting is not correct, an accurate oxygen consumption rate cannot be obtained.

  For example, FIG. 3 shows an example of a two-tank oxygen consumption rate test. It can be seen that the dissolved oxygen concentration starts to decrease by adding waste water to activated sludge at the elapse of 7 minutes in the figure and starting metabolism and decomposition. After the elapse of 14 minutes, the sample in the second tank is replaced with the sample in the first tank by the liquid feed pump set to operate when the dissolved oxygen concentration becomes 1 mg / L or less, and the dissolved oxygen concentration rises again. To do. After 15 minutes, the dissolved oxygen concentration begins to decrease again due to metabolism and decomposition. Thereafter, after 19 minutes, the dissolved oxygen concentration rises again by operating the liquid feed pump. Thereafter, the same operation was repeated, and after about 100 minutes, the metabolism and decomposition of the components in the wastewater was completed, and it is thought that only oxygen consumption due to endogenous breathing occurred, and the decrease in the dissolved oxygen consumption rate was moderate. .

  The analysis at this time takes a time range of 7 minutes to 14 minutes in which the dissolved oxygen concentration continuously decreases, and obtains the slope. The result is shown in FIG. However, since the oxygen consumption rate is positive for dissolved oxygen consumption, the oxygen consumption rate is plotted to be positive if the slope of the dissolved oxygen concentration becomes negative.

  As a result, the oxygen consumption rate from 7 to 14 minutes is calculated as 0.1 to 0.6 mg / L / min. In addition, during the time period when the dissolved oxygen concentration rises from 14 minutes to 15 minutes, the dissolved oxygen consumption due to metabolism and decomposition by activated sludge cannot be measured, and the oxygen consumption rate is 0 mg / L / min or less. Thereafter, similar analysis results are obtained, and after about 100 minutes, the oxygen consumption rate decreases to 0.03 mg / L / min.

  The problem at this time is that it is not clear which oxygen consumption rate value is correct. In other words, it is difficult to determine which time zone the oxygen consumption rate value should be looked at unless it is a skilled engineer. Even in the time zone of 7 to 14 minutes as an example, the oxygen consumption rate varies, and the time zone of 14 to 15 minutes is affected by the liquid feed pump and should not be adopted as the oxygen consumption rate. Therefore, it is difficult to discriminate which range is appropriate for the dissolved oxygen concentration data to be inclined.

  Furthermore, the oxygen consumption rate at 15 minutes, 20 minutes, 25 minutes, and 65 minutes has temporarily increased from 1.5 mg / L / min to 2.0 mg / L / min. It is considered that the dissolved oxygen concentration apparently rapidly decreased due to bubbles adhering to the tip and peeling off. Such a temporary increase in the oxygen consumption rate is usually not observed in the metabolism / decomposition of the components in the wastewater by the activated sludge, so it is considered unsuitable as the oxygen consumption rate. Therefore, it is thought that it is necessary to set in advance how much variation in oxygen consumption rate is allowed. However, because there are various fluctuation factors of the oxygen consumption rate test device, inappropriate data is discriminated from the analysis result. It is not easy to do without a skilled technician.

  Further, as described above, when bubbles are attached to the tip of the dissolved oxygen electrode, the accuracy of the dissolved oxygen concentration is lowered and the oxygen consumption rate cannot be measured correctly. For this reason, when the 2-tank type dissolved oxygen measuring tank is 150 mL, a relatively large flow rate of 450 mL / min is required when, for example, three times the amount is used for replacement in 1 minute for replacement. This is because the sample water that is continuously aerated in the tank is likely to flow into the second tank while containing bubbles before the bubbles rise to the water surface and are diffused into the atmosphere.

  The present invention solves the problems of the conventional method for measuring the oxygen consumption rate described above, and measures the sludge activity more easily, with less variation by the measurer, and with aeration bubbles. An object of the present invention is to provide an activated sludge degree measuring apparatus and an activated sludge degree measuring method which are less likely to cause errors and can be measured.

  Usually, in order to assess the degree of activity of how metabolizing and degrading is being carried out, that is, sludge activity, in order to evaluate how quickly the substrate in the wastewater is degraded, The sludge activity is evaluated by analyzing the substrate concentration and determining the substrate decomposition rate. However, there are various types of substrates in normal wastewater, and it is not always possible to qualitatively and quantitatively determine the concentration of each substrate. It is difficult to quantify each. For example, various organic substances are contained in sewage, and it is difficult to identify organic substance components.

  On the other hand, oxygen consumption occurs when the substrate is decomposed aerobically. Therefore, it is considered that this oxygen consumption rate is used as an index to measure how quickly sludge metabolism and decomposition occur. The technology based on this concept is the oxygen consumption rate test, but this oxygen consumption rate test aims to analyze metabolic and degradation processes analytically based on the change over time in the oxygen consumption rate. Skilled techniques and advanced analysis techniques are required.

  Therefore, the inventors continuously aerated the first tank and measured the dissolved oxygen concentration batchwise in the second tank, as in the measurement method using the two-tank oxygen consumption rate test apparatus in FIG. Then, instead of returning to the tank that is constantly aerated in the first tank, the sample that was continuously aerated in the first tank is continuously introduced into the reaction path, and a new aeration is performed in the reaction path. Instead, oxygen is consumed by the activated sludge reaction, and before and after the reaction path, the dissolved oxygen concentration at the start point of the reaction path and the dissolved oxygen concentration at the end point of the reaction path are respectively continuous by two dissolved oxygen electrodes. It was found that the above-mentioned problems can be solved by continuously measuring the sludge activity and continuously obtaining the sludge activity from the difference.

Specifically, the present invention includes the following [1] to [11]:
[1] An aeration container for aeration of activated sludge and a liquid mixture containing a substrate decomposed by activated sludge;
A reaction path that exists outside the aeration container, decomposes the substrate in the aerated mixture with the activated sludge and oxygen in the mixture, and consumes oxygen in the mixture;
Liquid feeding means for continuously drawing out the aerated mixture from the aerated container and returning it to the aerated container via the reaction path;
A dissolved oxygen concentration measuring means 1 and a dissolved oxygen concentration measuring means 2 for continuously measuring the dissolved oxygen concentration of the mixed solution respectively on the upstream side and the downstream side of the reaction path;
And the sludge activity can be determined by the difference between the dissolved oxygen concentration measured by the dissolved oxygen concentration measuring means 1 and the dissolved oxygen concentration measured by the dissolved oxygen concentration measuring means 2. Sludge activity measuring device.

  [2] The apparatus further includes a calculating means for calculating the difference between the dissolved oxygen concentration measured by the dissolved oxygen concentration measuring means 1 and the dissolved oxygen concentration measured by the dissolved oxygen concentration measuring means 2 to obtain the sludge activity. The device according to [1] above, wherein

  [3] The apparatus according to [1] or [2], wherein the liquid feeding unit is capable of adjusting a liquid feeding flow rate of the mixed liquid.

  [4] The reaction path has a plurality of paths, and the distance between the dissolved oxygen concentration measuring means 1 and the dissolved oxygen concentration measuring means 2 can be changed by a flow path switching valve. The apparatus according to any one of [1] to [3].

  [5] The apparatus according to any one of [1] to [4], wherein at least one of the reaction path and the aeration container can be kept at a constant temperature.

  [6] The dissolved oxygen concentration measuring means 1 and the dissolved oxygen concentration measuring means 2 are each formed by providing a dissolved oxygen concentration measuring device in a flow type dissolved oxygen measuring tank [1] ] The apparatus of any one of [5].

  [7] A method for measuring sludge activity, wherein the sludge activity is measured using the sludge activity measuring device according to any one of [1] to [6].

  [8] A method for measuring sludge activity using the sludge activity measuring device according to [3], [5], [6], wherein the reaction path is adjusted by adjusting the flow rate of the liquid feed pump. The measuring method of sludge activity characterized by adjusting reaction time of.

  [9] A method for measuring sludge activity using the sludge activity measuring device according to any one of [4] to [6], wherein the dissolved oxygen concentration measuring means is provided by the flow path switching valve. The measuring method of the sludge activity characterized by changing the distance between 1 and the said dissolved oxygen concentration measuring means 2, and adjusting activated sludge reaction time.

  [10] The liquid according to any one of [7] to [9], wherein the liquid containing a substrate decomposed by the activated sludge is wastewater discharged in a process of producing coke from coal. Method for measuring sludge activity in water.

  [11] The liquid according to any one of [7] to [9], wherein the liquid containing the substrate decomposed by the activated sludge contains only one kind of substrate decomposed by the activated sludge. Method for measuring sludge activity in water.

  The present invention has the following effects.

  Skill required to obtain the oxygen consumption rate in the past by introducing activated sludge and wastewater aerated into the reaction path, measuring the dissolved oxygen concentration at the start and end points of the flow path, and taking the difference Analysis and / or appropriateness determination of oxygen consumption rate is not required, the sludge activity is simplified, there is less variation by the operator, and measurement errors due to aeration bubbles are less likely to occur. can do.

  In addition, since the replacement of the sample is not necessary compared to the two-tank oxygen consumption rate test, the amount of liquid can be reduced, thereby extremely reducing the amount of bubbles contained in the sample at once. Since the adhesion of bubbles to the dissolved oxygen electrode can be extremely reduced and the dissolved oxygen concentration can be measured stably, the sludge activity can be determined stably.

It is a figure which shows one example of the sludge activity measuring apparatus of this invention. It is a figure which shows one example of the oxygen consumption measuring device of a prior art. It is a figure which shows the time-dependent change of the dissolved oxygen concentration by the 2 tank type oxygen consumption rate test of a prior art. It is a figure which shows the time-dependent change of the oxygen consumption rate by the 2 tank type oxygen consumption rate test of a prior art. It is a figure which has a plurality of reaction paths of the present invention and shows means for branching by a valve. It is a figure which shows the result of the dissolved oxygen concentration and activated sludge degree in Example 1 of this invention. It is a figure which shows the result of the activated sludge degree and flow velocity in Example 2 of this invention. It is a figure which shows the result of the activated sludge degree in Example 3 of this invention. It is a figure which shows the influence of the temperature of the activated sludge degree in Example 4 of this invention. It is a figure which shows the result of the dissolved oxygen concentration and activated sludge degree in Example 5 of this invention.

  FIG. 1 is a diagram illustrating a flow of a sludge activity measuring apparatus according to the present invention.

As shown in FIG. 1, an activated sludge measuring apparatus 1 according to the present invention is an aeration container 5 in which a mixture of a liquid 2 containing activated substrate and a sludge 3 containing a substrate is aerated by an aeration means 4. When,
A reaction path 9 that exists outside the aeration container 5 and decomposes the substrate in the aerated mixture with activated sludge 3 and oxygen in the mixture, and consumes oxygen in the mixture;
A liquid feed means 8 for continuously extracting the aerated mixture from the aeration container 5 and returning it to the aeration container 5 via the reaction path 9;
A dissolved oxygen concentration measuring means 7 and a dissolved oxygen concentration measuring means 11 for continuously measuring the dissolved oxygen concentration 6 and the dissolved oxygen concentration 10 of the mixed solution on the upstream side and the downstream side of the reaction path 9 respectively;
By calculating the difference between the dissolved oxygen concentration 6 measured by the dissolved oxygen concentration measuring means 10 and the dissolved oxygen concentration 7 measured by the dissolved oxygen concentration measuring means 11 by the sludge activity calculating means 12, the sludge activity is calculated. It is a sludge activity measuring device characterized by being able to obtain the degree.

  Sludge activity can be taken as an indicator of how actively metabolizing and decomposing. Although there are several indexes indicating the degree of activity, in the present invention, in order to see how fast metabolism and decomposition proceed, attention was paid to the amount of dissolved oxygen consumption. That is, it is considered that the greater the oxygen consumption when the substrate decomposed by the activated sludge contained in the wastewater is rapidly and aerobically decomposed, the higher the sludge activity.

  The liquid 2 containing the substrate that is decomposed by the activated sludge here shows, as an example, coke wastewater containing phenol, thiosulfuric acid, thiocyan, etc. generated from a coke plant in an ironworks (hereinafter referred to as a substrate that is decomposed by activated sludge). The liquid 2 contained is also simply referred to as drainage 2). However, the scope of application of the present invention is not limited to the substrate that is decomposed by the activated sludge in coke wastewater, such as industrial wastewater from food factories, chemical industry, pharmaceutical industry, painting industry, textile industry, dyeing industry, It can also be applied to substrates that are decomposed by activated sludge contained in factory wastewater.

  Instead of the liquid 2 containing the substrate to be decomposed by the activated sludge, a liquid containing a predetermined substrate can be used to determine the activated sludge degree when decomposing the predetermined substrate. For example, coke wastewater contains substrate components such as phenol, thiosulfuric acid, and thiocyanate, and by adding phenol, thiosulfuric acid, thiocyan, etc. with reagents, measure the oxygen consumption when each component is metabolized alone. Can do.

  The activated sludge 3 is not particularly specified, but is not limited to the above-described wastewater, but is sludge containing organisms that are treating a liquid containing a substrate that is decomposed by some activated sludge.

  In the aeration means 4, after collecting the air, the air is blown into the mixture of the waste water 2 and the activated sludge 3 in the aeration container 5. Although the method is not specified, the compressed air in the factory can be used as it is, or air can be blown in with a compressor, an air pump, or the like.

  The aeration container 5 is a container for putting a mixture of the waste water 2 and the activated sludge 3 into the aeration. It is desirable that the structure has no water leakage and is not significantly deteriorated or damaged due to the characteristics of the drainage. Although the container is not specified, a plastic container, a glass container, or the like can be used.

  Instead of the aeration container 5, a mixture of waste water and activated sludge can be introduced directly from the on-site aeration tank into the dissolved oxygen concentration measuring means 7, and the sludge activity can be measured in the same procedure. The mixture of the waste water and the activated sludge after the dissolved oxygen measurement may be returned to the on-site aeration tank again.

  The dissolved oxygen concentration measuring means 7 and the dissolved oxygen concentration measuring means 11 are means for measuring the dissolved oxygen concentration 6 in the waste water 2 and activated sludge 3 immediately after aeration, and the dissolved oxygen concentration measuring means 10 is at the starting point of the reaction path. The dissolved oxygen concentration 6 is measured, and the dissolved oxygen concentration measuring means 11 measures the dissolved oxygen concentration 10 at the starting point of the reaction path. As long as the reaction of the activated sludge 3 is not so fast, the dissolved oxygen concentration 6 on the upstream side of the reaction path 9 becomes the saturated dissolved oxygen concentration. For example, the saturated dissolved oxygen concentration under the condition of 1 atm and 25 ° C. is 8.11 mg / L.

  Moreover, although the principle of dissolved oxygen measurement is not specified, the diaphragm type and the fluorescence type are generally used. The diaphragm type is a conventionally used method for measuring dissolved oxygen. After dissolved oxygen permeates the diaphragm, the dissolved oxygen concentration is measured from the current value generated when an oxidation-reduction reaction is caused on the surface of the metal electrode. The fluorescence method is a method for measuring dissolved oxygen that has been spreading in recent years.A substance whose fluorescence level changes according to the dissolved oxygen concentration is fixed on the electrode surface, and the dissolved oxygen concentration is calculated from the fluorescence intensity generated when irradiated with excitation light. taking measurement.

  In addition, the method of measuring dissolved oxygen is not limited, but preferably the flow method is better than the batch method, and the batch method causes a residence time in the batch container, and the reaction in the batch container proceeds. The dissolved oxygen concentration value is not an instantaneous value. In order to evaluate the sludge activity more accurately, the flow type with a small volume and a short residence time is better when measuring dissolved oxygen.

  In addition, according to the present invention, the method for measuring the dissolved oxygen concentration is a flow method, so that the residence time in the dissolved oxygen measuring tank can be minimized and the decrease in the dissolved oxygen concentration can be measured more quickly. That is, in the flow type, since the volume of the dissolved oxygen measuring tank is small, when considering the influence of the residence time, the amount of liquid fed can be kept relatively small, so a pump with a small flow rate may be used. Since it is a flow type, the volume can be set to several mL (less than 10 mL, further 5 mL or less or 3 mL or less. However, from the viewpoint of measurement accuracy, it is preferably 1 mL or more). Even if it is made to flow, the discharge amount of 10 to 20 mL / min is sufficient. If the flow rate is low, the sample flows into the dissolved oxygen measuring tank with bubbles, and bubbles are attached to the dissolved oxygen electrode, as seen in the 2-tank oxygen consumption rate test. Therefore, it can be avoided that the oxygen consumption rate cannot be measured correctly.

  Although it does not specifically limit about the measuring apparatus using a flow type dissolved oxygen measuring tank, For example, DOA-32A by Toa DKK can be used.

  The liquid feeding means 8 continuously extracts the aerated mixed liquid from the aerated container 5. Although the method is not limited, a pump which is a device having a liquid feeding mechanism can be used. Since the amount of liquid to be fed can be adjusted according to the reaction time, an appropriate oxygen consumption can be easily measured even when the activity is different from that assumed. In previous oxygen consumption rate tests, once the test is started, a retest is required to change the sludge concentration in order to change the oxygen consumption. By changing the amount, the oxygen consumption can be measured with an appropriate reaction time.

  Although the reaction path 9 is not specified, it is a space for allowing the waste water 2 and the activated sludge 3 to react in the reaction path 9 for a certain period of time, and the substrate in the aerated mixed solution is used as the oxygen in the activated sludge 3 and the mixed solution. To consume oxygen in the mixture. It is assumed that the reaction path 9 can be a sealed space in which the drainage 2 and the activated sludge 3 are not newly aerated during measurement. The material may be a glass container, a plastic container, or a pipe such as a tube. Preferably, a spiral silicon tube or the like is preferable from the viewpoints of space saving, strength, and difficulty in attaching activated sludge to the inner wall.

  The reaction path 9 becomes longer as the volume of the reaction path 9 increases at a constant flow rate. Therefore, by providing a plurality of reaction paths in advance and branching by a valve, it is possible to easily measure an appropriate oxygen consumption even when the activity is different from the assumed one. An example is shown in FIG. In FIG. 4, a straight silicon tube 9a and a spiral silicon tube 9b are branched by a three-way cock valve 9c. Here, if it is found that the oxygen consumption is lower than expected, the reaction path is switched to the spiral silicon tube 9b in order to lengthen the reaction time, and conversely, the oxygen consumption is higher than expected. In this case, the reaction path can be switched to the straight silicon tube 9a in order to shorten the reaction time. The adjustment of the reaction path 9 can be adjusted more precisely by adjusting the amount of liquid fed in the liquid feeding means 8 together.

  In the liquid feeding means 8 and the reaction path 9, the reaction time can be adjusted, and by setting the dissolved oxygen concentration at the flow path end point to a certain level or more, the sludge activity can be appropriately obtained. However, if the reaction time is changed many times, standardization can be performed when performing relative evaluation with other sludge activity data.

  The reaction time can be adjusted by adjusting the liquid feed flow rate. One sample is introduced into the 50 mL reaction path at a constant flow rate of 5 mL / min, and a sludge activity of 3 mg / L is obtained at a reaction time of 10 minutes. The other sample is 50 mL at a constant flow rate of 2.5 mL / min. When introduced into the reaction path and the reaction time is 20 minutes and the sludge activity is 5 mg / L, relative evaluation is possible by obtaining the sludge activity per unit time. In the above example, when converted into the sludge activity per hour, it becomes 18 mg / L / hour and 15 mg / L / hour, respectively, which shows that the former sludge activity is high. However, as a precaution when performing this relative evaluation, after adjusting the flow rate in the liquid delivery means 8, particularly in the case of a diaphragm type in which the dissolved oxygen electrode is affected by the flow velocity, the dissolved oxygen concentration is fed until the dissolved oxygen concentration becomes stable. It is desirable to perform the liquid.

  Furthermore, in order to standardize the influence of the activated sludge concentration, it is also possible to obtain the sludge activity value per unit sludge amount by dividing the sludge activity by the sludge concentration. When the sludge activity is 20 mg / L / hour and the sludge concentration is 2,000 mg / L, it can be calculated as 0.01 mg-oxygen / L / hour / (mg-sludge / L).

  Also, as shown in FIG. 5, a plurality of paths can be prepared in advance, and the volume of the reaction path 9 can be adjusted by the flow path switching valve. After adjusting the volume, a certain sample is introduced into a 5 mL reaction path at a constant flow rate of 2.5 mL / min, and a sludge activity of 1 mg / L is obtained with a reaction time of 2 minutes. When it is introduced into the 50 mL reaction path at a constant 2.5 mL / min and the sludge activity is 5 mg / L at a reaction time of 20 minutes, the sludge activity per unit time is 30 mg / L / hour and 15 mg / L / hour, respectively. It can be seen that the former sludge activity is high.

  Strictly speaking, the volume of the reaction path is the volume between the inlet and outlet dissolved oxygen concentration measuring means, but between the dissolved oxygen concentration measuring means 7 and the reaction path 9, the reaction path 9 and dissolved oxygen concentration measuring means. When the volume is negligible, such as when 10 is directly connected, the volume of the reaction path 9 may be considered.

Further, in the reaction path 9, the metabolism / decomposition of activated sludge generally depends on the temperature, and there exists an optimum temperature range such as a medium temperature microorganism, a cold microorganism, and a thermophilic microorganism, and the optimum temperature. increases as the temperature rises specific growth rate in the range, the higher 10 ° C. When since it was known that the specific growth rate is Q ₁₀ laws doubled, thermostatic means for the purpose of maintaining the temperature constant It is desirable to have.

  The sludge activity can be determined by the difference between the dissolved oxygen concentration 6 before the reaction and the dissolved oxygen concentration 10 after the reaction.

  Furthermore, the sludge activity can be automatically calculated by the arithmetic device 12, and the difference can be accumulated to record the sludge activity over time and use it as a management index for comparing with past data. . Although the calculation method is not specified, it can be obtained simply by subtraction or the oxygen consumption rate per activated sludge concentration. Naturally, the residence time (min) is calculated from the reaction path volume (L) and the liquid flow rate (L / min), and the sludge activity (mg / L) is divided by the residence time, so that the oxygen consumption rate A value corresponding to (mg / L / min) can also be calculated.

  In addition, the sludge activity measuring device does not include the arithmetic unit 12, and the measured data of the dissolved oxygen concentration 6 before the reaction and the dissolved oxygen concentration 10 after the reaction are taken out of the system, and the difference between the two is obtained. The activated sludge degree may be calculated.

In the following examples, sludge activity was measured using the sludge activity measuring apparatus shown in FIG.
(Example 1) Evaluation of sludge activity in coke wastewater treatment FIG. 6 shows activated sludge used for coke wastewater treatment and simulated coke wastewater prepared with a reagent in an aeration container, and the sludge activity is measured according to the present invention. The results are shown. In the measurement, simulated coke effluent was put into an aeration container, and after the reaction route was first satisfied, activated sludge was added to the aeration container, and aeration was started at about 1 L / min. The feeding speed is 5 mL / min, the reaction path is 25 mL, and the reaction time is calculated as 5 minutes. As a result, the dissolved oxygen concentration at the start point of the reaction path was 6.1 to 6.4 mg / L, the dissolved oxygen concentration at the end point was 5.6 to 6.2 mg / L, and the sludge activity was 0.27 to 0.48 mg / L. L.

From this, the sludge activity could be obtained stably and continuously without using a skilled technique.
(Example 2) Sludge activity evaluation by switching reaction time In FIG. 7, activated sludge used for coke wastewater treatment and coke wastewater are put in an aeration container, and the flow rate of the feed pump is adjusted according to the present invention. The result of measuring the sludge activity is shown. In the measurement, the flow rate was switched from 10 mL / min to 20 mL / min, and the reaction path was set to 25 mL. Therefore, the reaction times correspond to 2.5 minutes and 1.25 minutes, respectively. The sludge activity showed the dissolved oxygen concentration decreased in each reaction time, and the sludge activity value tended to increase as the reaction time increased. The sludge activity at reaction time of 2.5 minutes and 1.25 minutes was 0.97 mg / L and 0.47 mg / L, respectively, and the sludge activity per unit time was 23.28 mg / L / hour, It was 22.56 mg / L / hour, and the sludge activity was considered to be about 23 mg / L / hour.

From this, in order to appropriately measure the sludge activity by the wastewater and activated sludge to be used, it is possible to adjust the reaction time by adjusting the flow rate of the liquid feed pump.
(Example 3) Evaluation of sludge activity by adding predetermined components FIG. 8 shows experimental conditions in which activated sludge and coke wastewater used for coke wastewater treatment are put in an aeration container, and activated sludge and wastewater. The results of measuring the sludge activity according to the present invention are also shown for the experimental conditions in which a single component (the substrate is one kind of thiocyanic acid) is added. In the wastewater, the sludge activity was about 2.5 mg / L, whereas in the single component, the sludge activity was about 0.25 mg / L. This suggests that 10% of the dissolved oxygen concentration of 2.5 mg / L required for decomposing the components in the wastewater is due to the added single component. Therefore, the decomposition activity of a desired substrate component can be determined by adding a desired substrate whose activity is to be measured.
Example 4 Sludge Activity Evaluation by Constant Temperature FIG. 9 shows that activated sludge containing iron-oxidizing bacteria and wastewater containing Fe ²⁺ ions are put in an aeration container. The result of measuring the sludge activity while keeping the temperature constant is shown. The activated sludge concentration is 24,000 mg / L, the Fe ²⁺ ion concentration is 400 mg / L, and the constant temperature condition is 5 to 30 ° C. Was measured and the average value was plotted. As a result, the sludge activity increased linearly with increasing temperature. From this, it was found that there is a temperature influence when measuring the sludge activity, and therefore, the sludge activity can be measured with high accuracy by keeping the temperature of the aeration container and / or the reaction path constant.
(Example 5) Sludge activity evaluation by directly introducing into a dissolved oxygen measuring tank from an aeration tank treating wastewater FIG. 10 shows a continuous low water treatment apparatus treating coke wastewater continuously. The result of evaluating the sludge activity of activated sludge in the continuous process of water-removal treatment equipment is shown by considering the water-treatment tank as an aeration container and introducing it directly into the dissolved oxygen measurement tank using a liquid feed pump. . The sludge concentration was 8,000 mg / L, and the water temperature was 30 ° C. Further, since the dissolved oxygen concentration in the aeration tank was about 3.5 mg / L, the dissolved oxygen concentration was 3.5 mg / L at the starting point of the reaction path. The end point of the reaction route was about 2 mg / L. Sludge activity was about 1.3 mg / L. Since the reaction path was 25 mL and the feeding speed was 5 mL / min, the reaction time was 5 minutes. From this and the sludge concentration, the sludge activity per unit sludge and unit time was 0.002 mg-oxygen / L / hour / (mg-sludge / L). From this, the sludge activity could be continuously obtained by directly introducing the sample from the aeration tank treating the wastewater into the dissolved oxygen measuring tank 1.

  As can be seen from Examples 1 to 5, the activity of sludge is measured more easily and with less variation by the measurer and less likely to cause measurement errors due to aerated bubbles. I was able to.

DESCRIPTION OF SYMBOLS 1 Sludge activity measuring device 2 Activated sludge 3 Liquid containing the substrate decomposed by activated sludge 4 Aeration means 5 Aeration container 6 Dissolved oxygen concentration 7 Dissolved oxygen concentration measuring means 8 Liquid sending means 9 Reaction path 10 Dissolved oxygen concentration DESCRIPTION OF SYMBOLS 11 Dissolved oxygen concentration means 12 Sludge activity calculation means 21 Oxygen consumption measuring device 22 Activated sludge 23 Liquid containing substrate decomposed by activated sludge 24 Aeration device 25 Aeration container 26 Dissolved oxygen concentration 27 Dissolved oxygen concentration meter 28 Solution feeding means 29 Dissolved oxygen concentration measuring tank 30 Stirrer 31 Stirrer 32 Dissolved oxygen electrode 33 Seal plug

Claims (10)

An aeration container for aeration of activated sludge and a mixture of liquids containing a substrate decomposed by activated sludge;
A reaction path that exists outside the aeration container, decomposes the substrate in the aerated mixture with the activated sludge and oxygen in the mixture, and consumes oxygen in the mixture;
Liquid feeding means for continuously drawing out the aerated mixture from the aerated container and returning it to the aerated container via the reaction path;
A dissolved oxygen concentration measuring means 1 and a dissolved oxygen concentration measuring means 2 for continuously measuring the dissolved oxygen concentration of the mixed solution respectively on the upstream side and the downstream side of the reaction path;
The reaction path has a plurality of paths, and the distance between the dissolved oxygen concentration measuring means 1 and the dissolved oxygen concentration measuring means 2 can be changed by a flow path switching valve.
Sludge activity can be obtained from the difference between the dissolved oxygen concentration measured by the dissolved oxygen concentration measuring means 1 and the dissolved oxygen concentration measured by the dissolved oxygen concentration measuring means 2. measuring device.   And a calculation means for calculating a sludge activity by calculating a difference between the dissolved oxygen concentration measured by the dissolved oxygen concentration measuring means 1 and the dissolved oxygen concentration measured by the dissolved oxygen concentration measuring means 2. The sludge activity measuring apparatus according to claim 1, wherein:   The sludge activity measuring apparatus according to claim 1 or 2, wherein the liquid feeding means is capable of adjusting a liquid feeding flow rate of the mixed liquid. The sludge activity measuring apparatus according to any one of claims 1 to 3 , wherein at least one of the reaction path and the aeration container can be kept at a constant temperature. Wherein the dissolved oxygen density measuring device 1 and the dissolved oxygen concentration measuring means 2, respectively, according to claim 1-4, characterized in that the flow-type dissolved oxygen measuring tank dissolved oxygen concentration measuring device is formed facilities The sludge activity measuring apparatus according to any one of the above. A method for measuring sludge activity, comprising measuring sludge activity using the sludge activity measuring device according to any one of claims 1 to 5 . A sludge activity measuring method using the sludge activity measuring device according to any one of claims 3 to 5 , wherein the reaction time in the reaction path is adjusted by adjusting a flow rate of a liquid feed pump. A method for measuring sludge activity, characterized by adjusting. Claim using sludge activity measuring apparatus according to any one of 1 to 5, the method of measuring the sludge activity, by the flow path switching valve, and the dissolved oxygen concentration measuring means 1, the dissolved A method for measuring sludge activity, wherein the distance between the oxygen concentration measuring means 2 is changed and the activated sludge reaction time is adjusted. The sludge activity according to any one of claims 6 to 8 , wherein the liquid containing a substrate that is decomposed by the activated sludge is wastewater discharged in a step of producing coke from coal. Measuring method. The liquid containing the substrate that is decomposed by the activated sludge contains only one type of substrate that is decomposed by the activated sludge, which has the sludge activity according to any one of claims 6 to 8 . Measuring method.

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