Method and device for measuring real yield of sludge through O2 / CO2 tracking

Abstract

The method for measuring the real yield of the sludge through O2 / CO2 tracking comprises the following steps: measuring O2 consumed by a microbial biochemical reaction in activated sludge and CO2 generated by the microbial biochemical reaction, and combining consumed NH3-N and COD (Chemical Oxygen Demand) concentration to synchronously measure the heterotrophic bacterium yield YH and the autotrophic bacterium yield YA; the synchronous measurement of the autotrophic bacteria and the heterotrophic bacteria can be realized at the same time, the actual value of the real yield of the sludge can be directly measured and calculated, the accuracy of the obtained real yield is not interfered by environmental factors, the measurement accuracy is high, the error is few, the cost is low, and the synchronous analysis of the competitive relationship between the autotrophic bacteria and the heterotrophic bacteria is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of sludge treatment, and in particular to the field of sludge treatment by 2 / CO 2 A method and device for tracking and measuring the actual yield of sludge. Background Art

[0002] Activated sludge refers to the general term for microbial communities and the organic and inorganic substances they are attached to. This type of activated sludge needs to fully react with microorganisms during treatment, and is now a commonly used method for improving water quality. Activated sludge is a biological substance produced by microorganisms through decomposition and anabolism with environmental substrates as the matrix. Therefore, the production of activated sludge is limited by the growth law of microorganisms. Microorganisms assimilate the matrix to grow when the substrate is sufficient, and oxidize themselves to die when the substrate is scarce. The dead cells after death can be reused by microorganisms under the action of enzymes. These pathways together constitute the growth cycle of activated sludge. At present, most domestic sewage treatment plants lack relevant supporting facilities for sludge treatment. A large amount of wet sludge is arbitrarily transported, simply landfilled or piled up, resulting in many cities being "besieged by sludge", which in turn causes the problem of residual sludge secondary pollution with lasting environmental impact. The key to solving this problem is not only to optimize the treatment and disposal technology after the residual sludge is produced, but more importantly, to start from the source governance concept and combine the sludge in-situ reduction technology in the sewage treatment process for joint remediation. To achieve this goal, it is necessary to have a deep understanding of the actual yield of activated sludge in the sufficient matrix stage. Since the true yield of activated sludge is the value of the amount of microorganisms produced by microbial degradation of unit mass of substrate, the traditional experimental method is to obtain the oxygen consumption by monitoring the changes in dissolved oxygen (DO) in the reactor, and then calculate OUR, and finally obtain the true yield of sludge. The accuracy of the obtained true yield is easily affected by the dissolved oxygen meter, test times and test environment.

[0003] Therefore, it is necessary to solve the technical problems of low measurement accuracy of traditional methods and the inability to synchronously measure autotrophic and heterotrophic bacteria, directly measure the actual value of the true sludge yield, and provide a theoretical basis for subsequent research. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a method for 2 / CO 2 The method and device for tracking and measuring the true yield of sludge can simultaneously realize the synchronous measurement of autotrophic bacteria and heterotrophic bacteria, and directly calculate the actual value of the true yield of sludge. The accuracy of the obtained true yield is not affected by other factors, and the measurement accuracy is high, the error is small, and the cost is low. At the same time, it is helpful to synchronously analyze the competitive relationship between autotrophic bacteria and heterotrophic bacteria.

[0005] The present invention is passed through 2 / CO 2The method for tracking and measuring the true productivity of sludge includes the following steps: measuring the O consumed by the biochemical reaction of microorganisms in the activated sludge 2 and the generated CO 2 , and combined with the consumed NH 3 -N and COD concentrations, and the heterotrophic bacteria yield Y is calculated simultaneously H and autotrophic bacteria yield Y A ;

[0006] Furthermore, the microorganisms in the activated sludge undergo oxidation reactions, and the autotrophic bacteria in the activated sludge consume O 2 and NH 3 -N, heterotrophic bacteria consume O 2 and COD and produces CO 2 , through CO 2 The absorbent absorbs the CO produced by heterotrophic bacteria 2， By CO 2 The weight gain of the absorbent gives the CO 2 Yield, O consumed by oxidation reaction 2 O consumed by autotrophic and heterotrophic bacteria 2 ;

[0007] Furthermore, the CO 2 The absorbent is NaOH solution, and the heterotrophic bacteria yield Y H The calculation formula is:

[0008] CO 2 (g) + 2NaOH (aq) = Na 2 CO 3 (aq)+H 2 O (l);

[0009]

[0010] Among them, ΔC is the amount of COD consumed by the reaction, mg / L; ΔO 1 is the amount of oxygen consumed by heterotrophic bacteria in the reaction, mg / L;

[0011] Further, the autotrophic bacteria yield Y A The calculation formula is:

[0012]

[0013] Where ΔN is the NH consumed in the reaction 3 -N amount, mg / L; ΔO 2 is the amount of oxygen consumed by the autotrophic bacteria in the reaction, mg / L.

[0014] The present invention also discloses a method of 2 / CO 2The device for tracking and measuring the actual sludge yield includes activated sludge biochemical reaction unit, CO 2 Absorption unit, oxygen supply unit and oxygen supply measurement unit, CO generated by activated sludge biochemical reaction unit 2 Enter CO 2 The absorption unit and oxygen supply unit replenish the consumed O2 in the activated sludge biochemical reaction unit. 2 , the oxygen supply measuring unit measures the amount of oxygen supplemented by the oxygen supply unit;

[0015] Furthermore, the activated sludge biochemical reaction unit, CO 2 The absorption unit and oxygen supply unit are sealed containers. The activated sludge biochemical reaction unit is sealed with oxygen. 2 Negative pressure is generated by consumption, and the oxygen supply unit and the activated sludge biochemical reaction unit are used for one-way flow to supplement the oxygen consumed by the activated sludge biochemical reaction unit. The oxygen supply is obtained by the liquid level difference formed by the oxygen supply unit and the oxygen supply measurement unit when supplying oxygen;

[0016] Furthermore, the CO 2 The sealed container of the absorption unit contains NaOH solution, and the sealed container of the oxygen supply unit contains pure O 2 The sealed container of the oxygen supply unit and the activated sludge biochemical reaction unit are both located in a constant temperature water area. The oxygen supply measurement unit includes a water reservoir and an air column arranged in the water reservoir. The air column is connected to the oxygen supply unit. The sealed container of the activated sludge biochemical reaction unit is heated by a constant temperature water bath. The CO generated by the activated sludge biochemical reaction unit 2 CO is pumped in via an air compressor 2 The sealed container of the absorption unit reacts with the NaOH solution, and the remaining gas flows back to the biochemical reaction unit. The activated sludge biochemical reaction unit generates negative pressure due to oxygen consumption. The oxygen in the oxygen supply unit enters the activated sludge biochemical reaction unit through the check valve under the action of the air pump, causing the water level of the oxygen supply measurement unit to rise. The rising water level is O 2 consumption.

[0017] The beneficial effects of the present invention are: 2 / CO 2 The method and device for tracking and measuring the true yield of sludge can simultaneously realize the synchronous measurement of autotrophic bacteria and heterotrophic bacteria, and directly calculate the actual value of the true yield of sludge. The accuracy of the obtained true yield is not affected by environmental factors, and the measurement accuracy is high, the error is small, and the cost is low. At the same time, it is helpful to synchronously analyze the competitive relationship between autotrophic bacteria and heterotrophic bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0019] Figure 1 It is a schematic diagram of the device structure of the present invention. DETAILED DESCRIPTION

[0020] In this embodiment, 2 / CO 2 The method for tracking and measuring the true productivity of sludge includes the following steps: measuring the O consumed by the biochemical reaction of microorganisms in the activated sludge 2 and the generated CO 2 , and combined with the consumed NH 3 -N and COD concentrations, and the heterotrophic bacteria yield Y is calculated simultaneously H and autotrophic bacteria yield Y A Direct measurement of O consumption by heterotrophic and autotrophic bacteria 2 and the CO produced 2 It has the characteristics of high accuracy, few errors, and low cost. The heterotrophic bacteria yield YH and the autotrophic bacteria yield YA can be measured synchronously, which is helpful for synchronously analyzing the competitive relationship between autotrophic and heterotrophic bacteria, and has the advantage of saving time.

[0021] In this embodiment, the microorganisms in the activated sludge are subjected to oxidation reaction, and the autotrophic bacteria in the activated sludge consume O 2 and NH 3 -N, heterotrophic bacteria consume O 2 and COD and produces CO 2 , through CO 2 The absorbent absorbs the CO produced by heterotrophic bacteria 2， By CO 2 The weight gain of the absorbent gives the CO 2 Yield, O consumed by oxidation reaction 2 O consumed by autotrophic and heterotrophic bacteria 2 Activated sludge mainly includes heterotrophic bacteria and autotrophic bacteria. Both bacteria use oxygen as electron acceptor. During the biochemical reaction of activated sludge, CO is produced. 2 and consume O 2 The heterotrophic bacteria yield YH and the autotrophic bacteria yield YA can be calculated simultaneously.

[0022] In this embodiment, the CO 2 The absorbent is NaOH solution, and the heterotrophic bacteria yield Y H The calculation formula is:

[0023] CO 2 (g) + 2NaOH (aq) = Na 2 CO 3 (aq)+H 2 O (l);

[0024]

[0025] Among them, ΔC is the amount of COD consumed by the reaction, mg / L; ΔO 1 is the amount of oxygen consumed by heterotrophic bacteria in the reaction, mg / L;

[0026] The autotrophic bacteria yield Y A The calculation formula is:

[0027]

[0028] Where ΔN is the NH consumed in the reaction 3 -N amount, mg / L; ΔO 2 is the amount of oxygen consumed by autotrophic bacteria in the reaction, mg / L; activated sludge mainly includes heterotrophic bacteria and autotrophic bacteria, both of which use oxygen as electron acceptor. The CO produced by heterotrophic bacteria in activated sludge 2 CO 2 Absorption liquid absorption (as shown in formula (1), can be CO 2 The absorption liquid increases in weight to obtain CO 2 The heterotrophic bacteria yield was calculated by formula (2). At the same time, by supplementing the consumed O 2 Quantify and combine CO 2 The production amount can be calculated by formula (3) to obtain the autotrophic bacteria yield.

[0029] This embodiment also discloses a method of 2 / CO 2 The device for tracking and measuring the actual sludge yield includes an activated sludge biochemical reaction unit 2, a CO 2 The absorption unit 1, oxygen supply unit 3 and oxygen supply measurement unit 4, CO generated by the activated sludge biochemical reaction unit 2 2 Enter CO 2 The absorption unit 1 and the oxygen supply unit 3 replenish the consumed O2 to the activated sludge biochemical reaction unit 2. 2 , activated sludge biochemical reaction unit 2, CO 2 The absorption unit 1 and the oxygen supply unit 3 are connected to each other in a sealed state, and the oxygen supply measurement unit 4 measures the amount of oxygen added by the oxygen supply unit 3; the activated sludge biochemical reaction unit 2 is used for the biochemical reaction of the activated sludge. The biochemical reaction mainly refers to the oxidation reaction. The autotrophic bacteria and heterotrophic bacteria in the activated sludge consume oxygen, and the CO produced by the heterotrophic bacteria 2 CO 2 The absorption unit 1 can measure the oxygen consumption of heterotrophic bacteria, and the activated sludge biochemical reaction unit 2 generates negative pressure due to oxygen consumption, which makes the oxygen supply unit 3 absorb the consumed O 2 When the oxygen supply unit 3 supplies oxygen to the activated sludge biochemical reaction unit 2, the water level of the oxygen supply measurement unit is forced to rise. The rising water level is O 2The consumption, combined with the above formulas (1)-(3), can simultaneously calculate the heterotrophic bacteria yield YH and the autotrophic bacteria yield YA 。

[0030] In this embodiment, the activated sludge biochemical reaction unit 2, CO 2 The absorption unit 1 and the oxygen supply unit 3 are both sealed containers. 2 The oxygen supply unit 3 and the activated sludge biochemical reaction unit 2 are unidirectionally connected to supplement the oxygen consumed by the activated sludge biochemical reaction unit 2, and the oxygen supply is obtained by the liquid level difference formed by the oxygen supply unit 3 and the oxygen supply measuring unit 4 when supplying oxygen; the CO 2 The sealed container of the absorption unit 1 contains NaOH solution, and the sealed container of the oxygen supply unit 3 contains pure O 2 The sealed containers of the oxygen supply unit 3 and the activated sludge biochemical reaction unit 2 are both located in a constant temperature water area. The oxygen supply measurement unit includes a water reservoir 401 and an air column 402 disposed in the water reservoir 401. A one-way valve is disposed on the air column 402. The air column 402 is connected to the oxygen supply unit 3. In the sealed connection state, the sealed container of the activated sludge biochemical reaction unit 2 is heated in a constant temperature water bath. The CO generated by the activated sludge biochemical reaction unit 2 is 2 CO is pumped in via an air compressor 2 The sealed container of the absorption unit 1 reacts with the NaOH solution, and the remaining gas flows back to the biochemical reaction unit. The activated sludge biochemical reaction unit 2 generates negative pressure due to oxygen consumption, forcing the oxygen in the oxygen supply unit 3 to enter the activated sludge biochemical reaction unit 2 through the check valve under the action of the air pump, thereby causing the water level in the water reservoir 401 of the oxygen supply measurement unit to rise. The rising water level is O 2 For the convenience of measurement, CO 2 The sealed container of the absorption unit 1 is placed on a weighing device 101 (such as an electronic scale). 2 An aeration stone 102 is placed in the sealed container of the absorption unit 1 .

[0031] The system absorbs CO produced by the metabolism of sludge microorganisms in a constant temperature closed reactor. 2 This method reduces the impact of the external environment and the number of measurements on the final measurement results, and can obtain a more accurate heterotrophic bacteria yield (Y H ) and autotrophic bacteria productivity (Y A ).

[0032] Activated sludge biochemical reaction unit 2, CO 2 The absorption unit 1 and the oxygen supply unit 3 are both closed reactors, CO 2Absorption unit 1 contains CO 2 Absorbent, CO 2 The absorption unit 1 and the activated sludge biochemical reaction unit 2 are provided with a desiccant filter cap 5 at the outlet. The activated sludge biochemical reaction unit 2 is maintained at a reaction temperature by a constant temperature water bath to ensure the stability of sludge activity. The activated sludge biochemical reaction unit 2 is provided with a magnetic stirrer 201. There is a check valve 6 between the activated sludge biochemical reaction unit 2 and the oxygen supply unit 3. The oxygen supply unit 3 contains pure O 2 A flexible rubber tube is connected between the oxygen supply unit 3 and the oxygen supply measuring unit 4. The activated sludge biochemical reaction unit 2 can provide a quantitative carbon source for the sludge through the injector 7. The oxygen supply measuring unit 4 and the oxygen supply unit 3 are water containers and maintain the liquid level difference between the two water containers during the reaction (the liquid level difference between the oxygen supply measuring unit 4 and the oxygen supply unit 3 is used to adjust the pressure difference. The oxygen supply measuring unit 4 slowly floats up with the reaction to ensure a certain positive pressure. A measuring cylinder for measuring oxygen consumption is set in the oxygen supply measuring unit 4.

[0033] In this embodiment, 2 / CO 2 The method of using the device to track and measure the actual yield of sludge is as follows: Activated sludge mainly includes heterotrophic bacteria and autotrophic bacteria. Both bacteria use oxygen as an electron acceptor. When the system is running stably, the CO produced by heterotrophic bacteria in the activated sludge 2 Under the action of the air pump, it enters unit a along with the air in unit b and is heated by the CO in unit a. 2 Absorption of the absorption liquid (as shown in formula (1), CO can be obtained by the weight gain of a unit 2 The heterotrophic bacteria yield can be calculated by formula (2). At the same time, units a and b will 2 Negative pressure is generated by consumption, which is partly caused by O 2 replenished and measured by the d unit (measures all consumed O 2 , and combined with CO 2 The production amount can be calculated by formula (3) to obtain the autotrophic bacteria yield).

[0034] Test Example 1

[0035] An endogenous respiration experiment was used to determine whether the device is suitable for measuring endogenous respiration SOUR. 1.5L of clean water and 1.5L of spare sludge were added to the activated sludge biochemical reaction unit 2, and the sludge concentration was 1000mg / L. The reaction was carried out for 5h, and the oxygen consumption and SOUR were recorded every hour. The SOUR (mgO 2 / gMLSS·min) were 0.132, 0.134, 0.133, 0.132, 0.135, and the average value was 0.1332mgO 2 / gMLSS·min.

[0036] Test Example 2

[0037] Sludge yield measurement experiment: 0.5L of clean water and 0.5L of spare sludge were added to the activated sludge biochemical reaction unit 2. At this time, the sludge concentration was 3000mg / L and COD Cr The concentration is 30.8 mg / L, NH 3 -N concentration is 0mg / L, COD is added by syringe Cr and NH 3 -N 40mg and 15mg.

[0038] After 20 minutes of reaction, the total oxygen consumption was measured by the measuring cylinder to be 39.32 mg, and the effluent COD Cr The concentration is 31.6 mg / L, and the effluent NH 3 -N concentration was 9.42 mg / L, unit (a) gained 30.88 mg / L, and combined with the endogenous respiration rate measured earlier, the cumulative oxygen consumption of the device was 46.62 mg, the cumulative oxygen consumption of exogenous respiration of heterotrophic bacteria was 14.48 mg, and the cumulative oxygen consumption of exogenous respiration of autotrophic bacteria was 24.16 mg.

[0039] Therefore, the heterotrophic bacteria productivity coefficient is:

[0040] Y H =((40+30.8-31.6)-(14.48)) / (40+30.8-31.6)=0.631mgCOD Cr / mgCOD Cr ;

[0041] Autotrophic bacteria productivity coefficient:

[0042] Y A =(4.57*(15-9.42)-(24.16)) / (15-9.42)=0.24mgCOD Cr / mgNH x -N.

[0043] (The above experimental data are the average values ​​of 3 measurements)

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for measuring the true yield of sludge by O2 / CO2 tracking, characterized in that: The following steps are included: by measuring the O2 consumed and CO2 produced by the biochemical reaction of microorganisms in the activated sludge, and combining the consumed NH3-N and COD concentration, the heterotrophic bacteria yield Y is calculated simultaneously. H and autotrophic bacteria yield Y A .

2. The method for measuring the true yield of sludge by O2 / CO2 tracking according to claim 1, characterized in that: The microorganisms in the activated sludge undergo oxidation reactions. The autotrophic bacteria in the activated sludge consume O2 and NH3-N, and the heterotrophic bacteria consume O2 and COD and produce CO2. The CO2 absorbent absorbs the CO produced by the heterotrophic bacteria. 2， The CO2 production is obtained from the weight gain of the CO2 absorbent, and the O2 consumed in the oxidation reaction is the O2 consumed by the autotrophic bacteria and the heterotrophic bacteria.

3. The method for measuring the true yield of sludge by O2 / CO2 tracking according to claim 2, characterized in that: The CO2 absorbent is NaOH solution, and the heterotrophic bacteria yield is Y H The calculation formula is: CO2(g)+2NaOH(aq)=Na2CO3(aq)+H2O (l); Among them, ΔC is the amount of COD consumed in the reaction, mg / L; ΔO1 is the amount of oxygen consumed by heterotrophic bacteria in the reaction, mg / L.

4. The method for measuring the true yield of sludge by O2 / CO2 tracking according to claim 3, characterized in that: The autotrophic bacteria yield Y A The calculation formula is: Among them, ΔN is the amount of NH3-N consumed in the reaction, mg / L; ΔO2 is the amount of oxygen consumed by the autotrophic bacteria in the reaction, mg / L.

5. A device for measuring the true yield of sludge by tracking O2 / CO2, characterized in that: It includes an activated sludge biochemical reaction unit, a CO2 absorption unit, an oxygen supply unit and an oxygen supply measurement unit. The CO2 produced by the activated sludge biochemical reaction unit enters the CO2 absorption unit, the oxygen supply unit replenishes the consumed O2 to the activated sludge biochemical reaction unit, and the oxygen supply measurement unit measures the amount of oxygen replenished by the oxygen supply unit.

6. The device for measuring the true yield of sludge by O2 / CO2 tracking according to claim 5, characterized in that: The activated sludge biochemical reaction unit, CO2 absorption unit and oxygen supply unit are all sealed containers. The activated sludge biochemical reaction unit generates negative pressure due to O2 consumption. The oxygen supply unit and the activated sludge biochemical reaction unit are used for one-way flow to supplement the oxygen consumed by the activated sludge biochemical reaction unit. The oxygen supply is obtained by the liquid level difference formed between the oxygen supply unit and the oxygen supply measuring unit when supplying oxygen.

7. The device for measuring the real yield of sludge by O2 / CO2 tracking according to claim 6, characterized in that: The sealed container of the CO2 absorption unit is filled with NaOH solution, and the sealed container of the oxygen supply unit is filled with pure O2. The sealed containers of the oxygen supply unit and the activated sludge biochemical reaction unit are both located in a constant temperature water area. The oxygen supply measurement unit includes a water reservoir and an air column arranged in the water reservoir. The air column is connected to the oxygen supply unit, and the sealed container of the activated sludge biochemical reaction unit is heated in a constant temperature water bath. The CO2 generated by the activated sludge biochemical reaction unit is pumped into the sealed container of the CO2 absorption unit by an air compressor pump to react with the NaOH solution, and the remaining gas flows back to the biochemical reaction unit. The activated sludge biochemical reaction unit generates negative pressure due to oxygen consumption. The oxygen in the oxygen supply unit enters the activated sludge biochemical reaction unit through a check valve under the action of the air pump, and causes the water level of the oxygen supply measurement unit to be forced to rise. The rising water level is the O2 consumption.

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