An emergency treatment method under the impact load of high-concentration organic pollutants

Abstract

The present invention belongs to the technical field of sewage treatment, and in particular relates to an emergency treatment method under the impact load of high-concentration organic pollutants. The present invention conducts anaerobic aeration on the biochemical pool and monitors the dissolved oxygen concentration in the biochemical pool, while controlling the DO concentration in the biochemical pool; then samples are taken from the front section, middle section, and end section of the anoxic pool of the biochemical pool respectively, the total organic carbon concentration of each section of the water sample is detected, and the average value is taken and substituted into the formula to calculate the nitrate concentration to be added; according to the above calculation results, a nitrate solution with a corresponding concentration is prepared, and then added to the anoxic pool, and the TOC concentration and nitrogen content in the anoxic pool after adding the nitrate solution are detected, and the ratio of TOC:N is (30-40):1. By accurately calculating the nitrate dosage, the present invention can quickly restore the sludge performance in 36 hours, enable the normal operation of the biochemical system, and the effluent reaches the standard for discharge.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and particularly relates to an emergency treatment method under the impact load of high-concentration organic pollutants. Background Art

[0002] High-concentration organic wastewater is wastewater mainly containing organic pollutants. It has a high concentration of organic substances, including carbohydrates, proteins, oils, lignin and other organic matters, which is likely to cause eutrophication of water quality, with great harm. Moreover, its composition is complex, the chromaticity is high, and it has an odor. When the influent water quality greatly exceeds the designed influent water quality for a long time, it will cause the sludge to turn black, the performance to deteriorate, and the biochemical pool to operate abnormally, resulting in continuous over-standard of the effluent water quality.

[0003] When the influent of existing sewage treatment plants is impacted by the load of high-concentration organic pollutants, the general method adopted by the sewage treatment plant operators is to stop the influent or reduce the influent volume. At the same time, the oxygen concentration in the biochemical pool is increased by adjusting the air volume of the blower. Generally, it takes about 7 days for the biochemical pool to resume normal operation and the effluent water quality to meet the discharge standards. Although this conventional method can make the sewage treatment plant resume normal operation, it takes a long time, and the accident adjustment pool of municipal sewage treatment plants generally cannot bear the influent volume for a continuous week. Moreover, the air volume of the blower may not meet the requirements. Therefore, there is an urgent need for an emergency treatment method to quickly respond to the impact load of high-concentration organic wastewater in municipal sewage treatment plants. Summary of the Invention

[0004] In order to overcome the above defects in the prior art, the present invention provides an emergency treatment method under the impact load of high-concentration organic pollutants. The present invention can quickly restore the sludge performance within 36h, make the biochemical system operate normally, and the effluent meet the discharge standards.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An emergency treatment method under the impact load of high-concentration organic pollutants, comprising the following steps:

[0007] S1. Carry out blank aeration (only aerate, without influent wastewater) on the biochemical pool and monitor the dissolved oxygen concentration (i.e., DO concentration) in the biochemical pool, and at the same time control the DO concentration in the biochemical pool;

[0008] S2. Take water samples from the front section, middle section and end section of the anoxic tank of the biochemical pool respectively, detect the total organic carbon concentration (i.e., TOC concentration) of each section of the water sample, take the average value, and substitute it into the formula to calculate the nitrate concentration to be added;

[0009] S3. Prepare a nitrate solution with a corresponding concentration according to the result obtained in step S2, then uniformly add it to the anoxic tank, and detect the TOC concentration and nitrogen (N) content in the anoxic tank after adding the nitrate solution, and the target ratio of TOC concentration to N is (30 - 40):1;

[0010] S4. Repeat the previous three steps until the sludge in the biochemical tank turns yellow, the TOC concentration drops within the design standard range of the water plant, and the entire biochemical tank can operate normally.

[0011] Preferably, the calculation formula for the nitrate concentration is as follows:

[0012]

[0013] Among them, NO X (t): The nitrate concentration in the anoxic tank at time t, unit mg / L;

[0014] S TOC (t): The TOC concentration in the anoxic tank at time t, unit mg / L;

[0015] b H : The endogenous respiration rate of heterotrophic bacteria under anoxic conditions, unit d -1 ;

[0016] b STO : The endogenous respiration rate based on the organic matter stored by heterotrophic bacteria, unit d -1 ;

[0017] Ss: The concentration of easily biodegradable organic matter in the initial influent of the anoxic tank, unit g / m 3 ;

[0018] Xs: The concentration of slowly biodegradable organic matter in the initial influent of the anoxic tank, unit g / m 3 ;

[0019] ΔTOC: The TOC concentration that the anoxic tank is set to finally drop to, unit mg / L;

[0020] Y H : The yield coefficient of denitrifying bacteria, unit mgMLVSS / mgNO 3 - N;

[0021] μ max : The maximum specific growth rate of denitrifying bacteria, unit d -1 ;

[0022] q T : The denitrification rate in the anoxic tank at a temperature of T °C, unit mgNO 3 - N / (mgMLVSS·d).

[0023] Preferably, the value of b H is 0.1d -1 ; the value of b STO is 0.1d -1 ; the value of Y H is 0.2 - 0.6 mg MLVSS / mg NO 3 - N; the value of μ max is 0.3 - 0.9 d -1 .

[0024] Preferably, in the calculation formula, q T = q 20 ×θ^ (T-20) ,

[0025] wherein, q 20 is the denitrification rate at 20°C, with the unit of mg NO 3 - N / (mg MLVSS·d); T is the measured temperature in the reaction tank, with the unit of °C; θ is the temperature coefficient.

[0026] Preferably, the value of θ is 1.09; the value of q 20 is 0.03 - 0.289 mg NO 3 - N / (mg MLVSS·d).

[0027] Preferably, in step S1, the DO concentration in the biochemical tank is controlled by adjusting the air volume of the blower; the DO concentration in the anoxic tank of the biochemical tank is 0 - 0.5 mg / L, and the DO concentration in the aerobic tank of the biochemical tank is 2 - 4 mg / L.

[0028] Preferably, when the biochemical tank is subjected to blank aeration in step S1, the original influent volume of the sewage treatment plant is stored in the accident adjustment tank of the sewage treatment plant.

[0029] The advantages of the present invention are as follows:

[0030] (1) This emergency treatment method is to add nitrate to the anoxic tank while subjecting the biochemical tank to blank aeration, so that the total organic carbon (TOC):N is controlled at (30 - 40):1, and the denitrification of nitrate nitrogen is used to remove the high-concentration TOC in the biochemical system, quickly turn the sludge yellow, and enable the system to quickly recover. The calculation method is to calculate the nitrate dosage required to reduce the total organic carbon to the normal concentration by regularly monitoring the TOC concentration in the biochemical tank and combining with denitrification kinetics, so as to avoid waste of chemicals caused by excessive nitrate dosage and excessive total nitrogen in the effluent; through accurate calculation of the nitrate dosage, the present invention can quickly restore the sludge performance in 36 h, enable the normal operation of the biochemical system, and the effluent meets the standard for discharge.

[0031] (2) The present invention adopts the method of adding nitrate to consume the high-concentration organic matter in the influent. The method is simple to operate, easy to implement, and has good effects; the calculation method is simple, the data to be detected is less, the parameters required in the formula can be obtained quickly, it is easy to calculate the concentration of nitrate to be added, and it is convenient to implement; moreover, the method has low cost and quick effect. After accurately adding nitrate and cooperating with conventional operations, the sewage treatment plant can generally resume normal operation in 36 hours, which has certain engineering application value; at the same time, it can alleviate the problems of insufficient volume of the accident adjustment tank and insufficient air volume of the blower in the sewage treatment plant.

[0032] (3) During the process of adding nitrate, it is necessary to regularly monitor and control the ratio of TOC:N in the anoxic tank to be (30-40):1 to maintain the most efficient denitrification rate. Specific embodiments

[0033] An emergency treatment method under the impact load of high-concentration organic pollutants, the steps are as follows:

[0034] S1. When it is found that the influent of the sewage treatment plant is affected by the impact load of high-concentration organic pollutants, the sludge in the biochemical tank turns black, and the effluent index is abnormal, immediately take the influent sample to recheck the influent TOC concentration, and quickly detect it every half hour to check whether the TOC concentration exceeds the standard of this sewage treatment plant, and refer to the design standard of the sewage treatment plant for other influent and effluent indexes;

[0035] S2. When the influent TOC concentration continuously exceeds the design standard by more than 5 times, the sludge in the biochemical tank gradually turns from yellow to black, and each effluent index exceeds the drainage standard, it indicates that the influent of this sewage treatment plant is affected by the impact load of high-concentration organic pollutants. At this time, stop the influent or reduce the influent volume, store the original influent volume of the sewage treatment plant in the accident adjustment tank, continue to aerate in the biochemical tank, and monitor the DO concentration in the biochemical tank. Specifically, the biochemical tank includes an anaerobic tank, an anoxic tank and an aerobic tank. In the present invention, it is necessary to adjust the air volume of the blower to control the DO concentration in the anoxic tank to be 0-0.5 mg / L and the DO concentration in the aerobic tank to be 2-4 mg / L;

[0036] The impact load of high-concentration organic pollutants will cause a sharp increase in the demand for dissolved oxygen in the aerobic tank. Therefore, it is necessary to timely adjust the air volume of the blower to control the DO concentration; if the dissolved oxygen in the aerobic tank is insufficient for a long time, it will lead to fewer microorganisms in the tank, decreased activity, loose structure, decreased removal rates of indexes such as TOC and ammonia nitrogen, and results such as blackening and aging of the sludge, which is not conducive to sludge recovery and continuous over-standard effluent.

[0037] S3. Detect the concentration Ss of easily biodegradable organic matter in the initial influent of the anoxic tank and the concentration Xs of slowly biodegradable organic matter in the initial influent of the anoxic tank. Take samples and detect the TOC concentration at the front section, middle section and end section of the anoxic tank respectively, take the average value, and substitute it into the formula to calculate the concentration of nitrate to be added;

[0038] Specifically, the calculation formula for nitrate concentration is as follows:

[0039]

[0040] where NO X (t): nitrate concentration in the anoxic tank at time t, unit mg / L;

[0041] S TOC (t): TOC concentration in the anoxic tank at time t, unit mg / L;

[0042] b H : endogenous respiration rate of heterotrophic bacteria under anoxic conditions, unit d -1 ;

[0043] b STO : endogenous respiration rate based on the organic matter stored by heterotrophic bacteria, unit d -1 ;

[0044] Ss: concentration of readily biodegradable organic matter in the initial influent of the anoxic tank, unit g / m 3 ;

[0045] Xs: concentration of slowly biodegradable organic matter in the initial influent of the anoxic tank, unit g / m 3 ;

[0046] ΔTOC: TOC concentration that the anoxic tank is set to finally reduce to, unit mg / L;

[0047] Y H : denitrifying bacteria yield coefficient, unit mgMLVSS / mgNO 3 - N;

[0048] μ max : maximum specific growth rate of denitrifying bacteria, unit d -1 ;

[0049] q T : denitrification rate in the anoxic tank at temperature T °C, unit mgNO 3 - N / (mgMLVSS·d);

[0050] Furthermore, qT = q 20 × θ^ (T-20) ,

[0051] where q 20 is the denitrification rate at 20 °C, unit mgNO 3 -N / (mgMLVSS·d); T is the measured temperature in the reaction tank, in °C; θ is the temperature coefficient;

[0052] S4. Prepare a nitrate solution with a corresponding concentration according to the result calculated in step 3, then uniformly add it to the anoxic tank, and detect the TOC concentration and nitrogen content in the anoxic tank after adding the nitrate solution, and control the target ratio of TOC concentration:N to be (30 - 40):1;

[0053] S5. Repeat the previous 4 steps until the sludge in the biochemical tank turns yellow, the TOC concentration drops within the design standard range of the water plant, and the entire biochemical tank can operate normally.

[0054] The value ranges of the parameters involved in the above calculation formula are as follows:

[0055] Symbol Parameter Name Range of Values <![CDATA[b H > Heterotrophic Bacteria Anoxic Endogenous Respiration Rate 0.1 <![CDATA[b STO > Endogenous Respiration Rate Based on Organic Matter Stored by Heterotrophic Bacteria 0.1 <![CDATA[Y H > Denitrifying Bacteria Yield Coefficient 0.2～0.6 <![CDATA[μ max > Maximum Specific Growth Rate of Denitrifying Bacteria 0.3～0.9 θ Temperature Coefficient 1.09 <![CDATA[q 20 > Denitrification Rate at 20°C 0.03～0.289

[0056] The content of high-concentration organic pollutants is quantitatively represented by TOC, excluding other pollutants such as heavy metals, and the wastewater does not cause the over-standard of influent nitrogen and phosphorus elements.

[0057] Example 1

[0058] A domestic sewage treatment plant in a certain town found through the influent online monitor that the influent was continuously abnormal, the TOC concentration was continuously above 5000 mg / L, resulting in the sludge color in the biochemical tank turning black and the effluent index exceeding the standard.

[0059] Adopt an emergency treatment method under the impact load of high-concentration organic pollutants provided by the present invention, including the following steps:

[0060] S1. After it is found that the influent of the sewage treatment plant is impacted by high-concentration organic pollutants, the sludge in the biochemical tank turns black, and the effluent index is abnormal, immediately take a re-inspection sample of the influent to detect the influent TOC concentration and the TOC concentration in the biochemical tank, and quickly detect it every half hour. The TOC concentration is always above 5000 mg / L, and the influent indexes such as nitrogen and phosphorus are all within the involved range, while the effluent index exceeds the standard of this sewage treatment plant according to the detection result of the online detector;

[0061] S2. After confirming the abnormality, stop the influent, store the original influent volume of the sewage treatment plant in the accident regulation tank of the sewage treatment plant, monitor the DO concentration in the biochemical tank, adjust the air volume of the blower, and control the DO concentration in the anoxic tank to be 0 - 0.5 mg / L and in the aerobic tank to be 2 - 4 mg / L;

[0062] S3. Take water samples from the front section, middle section and end section of the anoxic tank respectively, detect the TOC concentration of the water samples, and take the average value as 6000 mg / L, and substitute it into the formula to calculate the nitrate concentration to be added;

[0063] The values of the parameters used in this example are shown in the following table:

[0064] Symbol Parameter Name Range of Values <![CDATA[S TOC (t)]]> Average Value of Samples Taken from the Front, Middle, and Rear Ends of the Anoxic Tank at the Current Moment 6000 <![CDATA[b H > Heterotrophic Bacteria Anoxic Endogenous Respiration Rate 0.1 <![CDATA[b STO > Endogenous Respiration Rate Based on Organic Matter Stored by Heterotrophic Bacteria 0.1 <![CDATA[Y H > Denitrifying Bacteria Yield Coefficient 0.4 <![CDATA[μ max > Maximum Specific Growth Rate of Denitrifying Bacteria 0.3 θ Temperature Coefficient 1.09 ΔTOC TOC Concentration That the Anoxic Tank Is Set to Eventually Drop to 400 <![CDATA[q 20 > Denitrification Rate at 20°C 0.25

[0065] In the formula, the concentration Ss of readily biodegradable organic matter in the initial influent of the anoxic tank is 40% of the influent TOC concentration, and the value is 2400 g / m 3 ;

[0066] The concentration Xs of slowly biodegradable organic matter in the anoxic tank is 20% of the influent TOC concentration, and the value is 1200 g / m 3 ;

[0067] q T = q 20 × θ^ (T-20) = 0.25 × 1.09^ (20-20) = 0.25;

[0068]

[0069] S4. Prepare a nitrate solution according to the result calculated in step 3, then uniformly add it to the anoxic tank, and detect that the TOC:N in the anoxic tank after adding the nitrate solution is 35.93;

[0070] S5. Repeat the above three steps S2, S3, and S4 five times. After 36 h, the sludge in the biochemical tank of the sewage treatment plant turns yellow, and the TOC concentration drops to within the design standard range of 400 mg / L of the water plant, and the entire biochemical tank can operate normally.

[0071] It can be seen from the above embodiments that the present invention can quickly restore the sludge performance in 36 h by accurately calculating the nitrate dosage, enable the normal operation of the biochemical system, and the effluent reaches the standard for discharge.

[0072] The specific operations above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An emergency treatment method under the impact load of high-concentration organic pollutants, characterized in that, it comprises the following steps: S1. Carry out anaerobic aeration on the biochemical pool and monitor the DO concentration in the biochemical pool, and at the same time control the DO concentration in the biochemical pool; S2. Take water samples from the front section, middle section and end section of the anoxic tank in the biochemical pool respectively, detect the TOC concentration of each section of water sample, take the average value, and substitute it into the formula to calculate the nitrate concentration to be added; S3. Prepare a nitrate solution with a corresponding concentration according to the result calculated in step S2, then uniformly add it to the anoxic tank, and detect the TOC concentration and nitrogen content in the anoxic tank after adding the nitrate solution, and the target ratio of TOC concentration:N is (30-40):1; S4. Repeat the previous three steps until the sludge in the biochemical pool turns yellow, the TOC concentration drops to within the water plant design standard range, and the entire biochemical pool can operate normally; The calculation formula for the nitrate concentration is as follows: Among them, NO X (t): The nitrate concentration in the anoxic tank at time t, unit mg / L; S TOC (t): TOC concentration in the anoxic tank at time t, unit: mg / L; b H : Heterotrophic bacteria anoxic endogenous respiration rate, unit d -1 ; b STO : endogenous respiration rate based on the organic matter stored by heterotrophic bacteria, unit d -1 ; Ss: Concentration of readily biodegradable organic matter in the initial influent of the anoxic tank, unit: g / m 3 ; Xs: Concentration of slowly biodegradable organic matter in the initial influent of the anoxic tank, unit: g / m 3 ; ΔTOC: The TOC concentration that the anoxic tank is set to finally drop to, unit mg / L; Y H : Denitrifying bacteria yield coefficient, unit mg MLVSS / mg NO 3 - N; μ max : Maximum specific growth rate of denitrifying bacteria, unit d -1 ; q T : Denitrification rate in the anoxic tank at a temperature of T °C, unit mgNO 3 - N / (mgMLVSS·d).

2. The emergency treatment method under the impact load of high-concentration organic pollutants according to claim 1, characterized in that: The value of b H is 0.1d -1 ; The value of b STO is 0.1d -1 ; The value of Y H is 0.2 - 0.6 mg MLVSS / mg NO 3 - N; The value of μ max is 0.3 - 0.9 d -1 .

3. The emergency treatment method under the impact load of high-concentration organic pollutants according to claim 1, characterized in that: In the above calculation formula, q T = q 20 × θ ^(T-20) , Among them, q 20 is the denitrification rate at 20°C, with the unit of mgNO 3 - N / (mgMLVSS·d); T is the measured temperature in the reaction tank, with the unit of °C; θ is the temperature coefficient.

4. The emergency treatment method under the impact load of high-concentration organic pollutants according to claim 3, characterized in that: The value of θ is 1.09; the value of q 20 is 0.03 - 0.289 mg NO 3 - N / (mg MLVSS·d).

5. The emergency treatment method under the impact load of high-concentration organic pollutants according to claim 1, characterized in that: In step S1, the DO concentration in the biochemical pool is controlled by adjusting the air volume of the blower; the DO concentration in the anoxic tank in the biochemical pool is 0-0.5 mg / L, and the DO concentration in the aerobic tank in the biochemical pool is 2-4 mg / L.

6. The emergency treatment method under the impact load of high-concentration organic pollutants according to claim 1, characterized in that: When carrying out anaerobic aeration on the biochemical pool in step S1, the original influent volume of the sewage treatment plant is stored in the accident regulation pool of the sewage treatment plant.

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