CN104459081B - The assay method of a kind of activated sludge breathing rate and original position breathing rate instrument thereof - Google Patents

Abstract

The invention discloses a method for measuring the respiration rate of activated sludge and an in-situ respiration rate instrument thereof. The respiration rate meter includes a reactor, a pole, a stirring device, a dissolved oxygen probe and a data acquisition device; the reactor includes a base that can be opened and closed; the base of the reactor is connected to the pole; the The stirring and stirring device is set in the reactor; the dissolved oxygen probe is set in the reactor and connected with the data acquisition device. The invention can realize the in-situ measurement of the test point in the biochemical pool, and avoids the deviation of the measurement result caused by off-line measurement after sampling. The invention can realize rapid measurement of in-situ respiration rate, has fast response speed, and only needs 1 to 3 minutes for each measurement. The invention can be hand-held and portable for measurement, has simple operation, low price, and is convenient for popularization and application.

Description

A method for measuring the respiration rate of activated sludge and its in-situ respiration rate instrument

technical field

The invention relates to a method for measuring the respiration rate of activated sludge and an in-situ respiration rate instrument thereof.

Background technique

my country's sewage treatment plants urgently need to improve the operation level and realize the stable operation of the process. At present, microbial activity is mainly analyzed indirectly by observing the results of microbial reactions such as effluent water quality, and there is a lack of indicators that directly describe microbial activity. Therefore, the development of online monitoring methods for microbial activity and the simple testing and judgment of microbial activity can make up for the lack of existing process operation indicators, and are of great significance for adjusting operating parameters, stable and reliable operation, and improving effluent water quality. The respiration rate of activated sludge refers to the amount of dissolved oxygen consumed by a unit of activated sludge per unit time. The unit is mg/(L.min) or kg/(m ³ .hr), which can comprehensively reflect the aerobic biological treatment process. Microbial activity and organic degradation rate, so it has a good application prospect.

There are many methods for measuring respiration rate, and both laboratory and online instruments have mature methods. The more mature method in the laboratory is the Warburg respiration instrument, which requires the use of specialized equipment. In addition, there is a closed liquid phase measurement method, which uses a dissolved oxygen meter to measure the rate of change of dissolved oxygen in a closed mixed solution to calculate the respiration rate. Generally, only a dissolved oxygen meter, an Erlenmeyer flask and an electromagnetic stirrer are needed. In addition, there is a method of measuring gas-phase carbon dioxide concentration or oxygen consumption volume to indirectly calculate dissolved oxygen consumption. The above method has a variety of domestic or imported laboratory instruments. The main disadvantage is that the sludge needs to be sampled and stored, which cannot be used portablely on site, and it is difficult to measure the instantaneous respiration rate under the operating state of the process.

In terms of online instruments, it can be divided into open and closed methods. When the closed method is used to measure, the activated sludge inside the reactor is isolated from oxygen, and the decrease rate of the dissolved oxygen concentration is equal to the respiration rate of the sludge. The open measurement method is to continuously aerate, and calculate the activity parameters of the sludge by measuring the oxygen sag curve. At present, the main online instruments include Merit20, RODTOX, RA-1000 and other respiration measuring instruments, most of which are developed by foreign companies, expensive and difficult to popularize and apply. In addition, these methods also require sampling and pretreatment of sludge, which is difficult to test under the actual process operating conditions.

In the prior art, Chinese patent applications 201010579870.0 and 201020650138.3 disclose frequency conversion devices that use dissolved oxygen and sludge concentration signals to control blowers instead of breathing rate testing instruments. Chinese patent applications 201220526855.4, 200810105908.3 and 200810167716.5 all use laboratory methods to measure the respiration rate of microalgae, reservoir microorganisms and metazoans. Chinese patent applications 200810104254.2 and 200820080009.8 both use an external electric field to improve microbial activity, and have nothing to do with the respiration rate test. Chinese patent applications 200910082955.5 and 200910082957.4 are both control methods based on respiration rate. The respiration rate is obtained through data analysis through intermittent aeration in the SBR reactor. It does not involve a special respiration rate test device, and the test location and location cannot be changed at will. condition. Chinese patent application 201110195841.9 is a method for measuring the oxygen consumption rate constant of a river, and does not involve a test method for activated sludge, nor does it involve a special test device. Chinese patent application 200920107719.X is a teaching device designed using the principle of laboratory testing, which can only be used for laboratory demonstrations and cannot be used in actual sites. Chinese patent application 200620004632.6 is a respiration rate device based on bubble technology, which can be used for anaerobic and aerobic process tests. It belongs to laboratory test devices and is not suitable for field tests in sewage treatment plants.

Contents of the invention

The purpose of the present invention is to provide a method for measuring the respiration rate of activated sludge and its in-situ respiration rate instrument. The present invention can realize portable measurement in a biochemical pool, and quickly obtain microbial activity and influent load change parameters. The in-situ respiration rate meter of the present invention is based on a mature test principle, has the characteristics of simple structure, low cost, and reliable test, and can be used for various requirements such as the spatial distribution of respiration rate, the change of influent load, and the determination of oxygenation coefficient.

An in-situ respiration rate meter provided by the present invention includes a reactor, a support rod, a stirring device, a dissolved oxygen probe and a data acquisition device;

The reactor includes a base that can be opened and closed; the base of the reactor is connected with the support rod;

The stirring and stirring device is arranged in the reactor;

The dissolved oxygen probe is set in the reactor and connected with the data acquisition device.

In the above-mentioned in-situ respiration rate meter, the support rod is connected to the base through a steel wire rope.

In the above-mentioned in-situ respiration rate meter, the stirring device is arranged on the base.

In the above-mentioned in-situ respiration rate meter, the dissolved oxygen probe is arranged at the middle and upper part of the reactor.

In the above-mentioned in-situ respiration rate meter, the top of the reactor is provided with a through hole, which can be used to discharge the residual air in the mixed liquid in the reactor.

The present invention also provides the method utilizing above-mentioned in-situ respiration rate meter to measure the respiration rate of sludge, comprising the steps:

Place the in-situ respiration rate meter at the measurement point of the sludge, lower the support rod, separate the base from the main body of the reactor, and then the activated sludge mixture at the point to be measured enters the reactor inside the device;

elevating the strut to close the base to the main body of the reactor;

Start the stirring device to stir, and simultaneously record the dissolved oxygen concentration of the activated sludge in the reactor through the data acquisition device; calculate the rate of change of the dissolved oxygen concentration of the activated sludge over time, when the rate of change is stable The numerical value of the rate of change is the respiration rate of the measured sludge.

In the above method, the stirring time may be 1-3 minutes, and the dissolved oxygen concentration of the activated sludge is continuously measured during the whole stirring process.

The present invention has following beneficial effect:

The invention can realize the in-situ measurement of the test point in the biochemical pool, and avoids the deviation of the measurement result caused by off-line measurement after sampling. The invention can realize rapid measurement of in-situ respiration rate, has fast response speed, and only needs 1 to 3 minutes for each measurement. The invention can be hand-held and portable for measurement, has simple operation, low price, and is convenient for popularization and application.

Description of drawings

Fig. 1 is a schematic structural view of the in-situ respiration rate instrument of the present invention.

Fig. 2 is the physical figure of the in-situ respiration rate instrument of the present invention.

Fig. 3 is the change curve of the respiration rate obtained by the method of the present invention (in embodiment 1) and the traditional method.

Fig. 4 is the variation curve of the respiration rate obtained in Example 2 of the present invention.

Fig. 5 is the variation curve of the respiration rate obtained in Example 3 of the present invention.

The marks in the figure are as follows: 1 data acquisition device, 2 dissolved oxygen probe, 3 reactor, 4 base, 5 pole, 6 steel wire rope, 7 electric stirring device.

detailed description

The experimental methods used in the following examples are conventional methods unless otherwise specified.

The materials and reagents used in the following examples can be obtained from commercial sources unless otherwise specified.

Embodiment 1, in situ respiration rate meter

As shown in Figure 1, the in-situ respiration rate meter provided by the present invention includes a reactor 3, a pole 5, an electric stirring device 7, a dissolved oxygen probe 2 and a data acquisition device 1; the reactor 3 includes an openable base 4, and the pole 5 is connected with the base 4 through a steel wire rope 6, which is used to control the opening and closing between the base 4 and the body of the reactor 3; a through hole (not shown in the figure) is provided on the top of the reactor 3 ). The electric stirring device 7 is arranged in the cavity of the reactor 3 and is located on the base 4 . The dissolved oxygen probe 2 is set in the cavity of the reactor 3, and is located in the middle and upper part of the reactor 3, which is connected with the data acquisition device 1, and is used to measure the dissolved oxygen concentration of the sludge, and then calculate its respiration rate.

The working process of the in situ respiration rate meter of the present invention is as follows:

The wire rope 6 is lowered downward, and the base 4 of the reactor 3 falls due to gravity. At this time, the lower edge of the reactor 3 is opened from the base 4, and the internal liquid and the external environment begin to exchange. Move the pole 5, place it together with the reactor 3 at the designated measurement point, lift the wire rope 6, and close the base 4 and the lower edge of the reactor 3, and this process completes the sampling at the measurement point. After closing, immediately open the stirring device 7 to stir the sampled liquid. Start to record the dissolved oxygen concentration of the sample mixture for 1 to 3 minutes. After the computer 1 records the data of the whole measurement process, it calculates the breathing rate. Close the stirring device 7, then lower the steel wire rope 6, and empty the mixed solution in the reactor 3 to prepare for the next test.

The in-situ respiration rate meter of the present invention is used to measure the respiration rate of a certain sludge, and its variation curve with time is shown in FIG. 2 .

The standard method of airtight test is used as a control to measure the respiration rate of the same sludge. Use a sampler to obtain the mixed solution from the measurement position, fill the 250mL Erlenmeyer flask, put a magnetic stirrer in the bottle, insert a dissolved oxygen probe at the mouth of the bottle and seal it, so that the mixed solution fills the bottle and isolates it from the outside air. The whole is placed on a magnetic stirrer, and the rotating speed of the magnetic stirring bar is adjusted to completely mix the mixed solution in the bottle. At this time, the concentration data of the dissolved oxygen probe is collected, and the test results are shown in Figure 2.

It can be seen from Fig. 2 that the method of the present invention has a good consistency with the existing standard method. Because within 0 to 20 seconds of the start of the test, due to problems such as lag in the probe response of the dissolved oxygen meter, the change rate of dissolved oxygen showed a rapid decline. After 20 seconds, the rate of change gradually stabilizes, and the probe of the dissolved oxygen meter reaches a steady-state response. The value at this time is the respiration rate value, which is 0.7mg/(L.min) as shown in the figure. Therefore, the respiration rate can be calculated by taking the dissolved oxygen data after 30 seconds.

Embodiment 2, measure the respiration rate of the activated sludge of different depths in the biochemical pool

The instantaneous respiration rate at different depths was measured in the aerobic section of the AAO process in a sewage treatment plant.

Select three measurement points such as 0 meter, 1 meter and 2 meters from the surface of the mixed liquid, use the in-situ respiration rate meter in Example 1 to measure the instantaneous respiration rate of the above-mentioned measurement points, each measurement is completed in 60 seconds, take Respiration rate was calculated from the last 30 seconds of data.

The specific test steps are in accordance with the use process of the respiration rate meter in Example 1. The test results were respectively mean 0.29mg/(L.min), 0.14mg/(L.min) and 0.39mg/(L.min).

This embodiment reflects that the respiration rates of different depths of biochemical pools are significantly different.

The schematic diagram of the positions of the sampling points in this embodiment is shown in Fig. 4(a), and the obtained respiration rate curve is shown in Fig. 4(b).

Embodiment 3, measure the respiration rate of the activated sludge at different positions of the same depth in the biochemical pool

In the aerobic section of the AAO process of a sewage treatment plant, the instantaneous respiration rate at different plane positions was measured at 1 meter below the water surface.

Select 6 measuring points evenly distributed in the aeration tank, use the in-situ respiration rate instrument in Example 1 to measure the instantaneous respiration rate of the above-mentioned measuring points, each measurement is completed within 60 seconds, and the data of the last 30 seconds is taken to calculate the respiration rate .

The specific test steps are in accordance with the use process of the respiration rate meter in Example 1. The test results were respectively mean 0.22mg/(L.min), 0.23mg/(L.min), 0.26mg/(L.min), 0.31mg/(L.min), 0.21mg/(L.min) and 0.29mg/(L.min).

This example reflects the difference in respiration rate at different locations of the biochemical pool due to differences in substrate mixing and sludge concentration.

The schematic diagram of the positions of the sampling points in this embodiment is shown in Fig. 5(a), and the obtained respiration rate curve is shown in Fig. 5(b).

Claims (2)

1. A respiration rate instrument in situ, characterized in that: the respiration rate instrument comprises a reactor, a pole, a stirring device, a dissolved oxygen probe and a data acquisition device; The reactor includes a base that can be opened and closed; the base of the reactor is connected to the support rod; the support rod is connected to the base through a steel wire rope; The stirring device is arranged in the reactor; the stirring device is arranged on the base; The dissolved oxygen probe is arranged in the reactor, which is connected with the data acquisition device; The dissolved oxygen probe is arranged at the middle and upper part of the reactor; The top of the reactor is provided with a through hole. 2. utilize the method for the said in-situ respiration rate instrument of claim 1 to measure the respiration rate of activated sludge, comprise the steps: The in-situ respiration rate meter is placed at the measurement point of the activated sludge, and the support rod is lowered to separate the base from the main body of the reactor, and then the activated sludge mixture at the point to be measured enters the inside the reactor; elevating the strut to close the base to the main body of the reactor; Start the stirring device to stir, and simultaneously record the dissolved oxygen concentration of the activated sludge in the reactor through the data acquisition device; calculate the rate of change of the dissolved oxygen concentration of the activated sludge over time, when the rate of change is stable The value of the rate of change at time is the respiration rate of the activated sludge; The stirring time is 1-3 minutes.