A method for adjusting water distribution in liquor wastewater treatment process

Abstract

The present invention belongs to the field of water treatment, and in particular, relates to a method for adjusting water distribution in a liquor wastewater treatment process, comprising the following steps: determining UASB reaction pool effluent TP, UASB reaction pool effluent VFA, hydrolysis acidification pool effluent TP, hydrolysis acidification pool effluent VFA, anaerobic pool effluent VFA and nitrification liquid nitrate-nitrogen content under current operating conditions, and determining the anaerobic pool wastewater carbon-phosphorus ratio, anoxic pool wastewater carbon-nitrogen ratio and nitrification liquid reflux ratio; substituting the measured and determined parameter values ​​into the calculation formula of the present invention, respectively calculating the amount of water entering the high-efficiency anaerobic treatment reaction pool, the amount of water flowing from the hydrolysis acidification pool effluent into the anaerobic pool and the amount of water flowing from the hydrolysis acidification pool effluent into the anoxic pool, and adjusting the water distribution of the liquor wastewater treatment process according to the calculation results. The method provided by the present invention can scientifically distribute the amount of water treated by different process sections, thereby achieving economical and efficient removal of wastewater pollutants without adding an external carbon source.

Description

Technical Field

[0001] The invention belongs to the field of water treatment, and in particular relates to a method for adjusting water distribution in a liquor wastewater treatment process. Background Art

[0002] In order to meet the wastewater discharge standards, the current wastewater treatment process often requires the addition of a large amount of carbon source to achieve denitrification, thereby achieving denitrification; or a large amount of coagulant needs to be added to achieve chemical phosphorus removal. However, this not only increases the operating cost, but also produces a large amount of sludge, leading to secondary pollution. More importantly, the added carbon source is difficult for denitrifying bacteria and polyphosphate bacteria to absorb, the utilization rate is low, and the effect is unsatisfactory. Therefore, there is an invention to treat the wastewater with different processes, one part of the water is intended to generate volatile fatty acids (VFA) that are easily utilized by denitrifying bacteria and polyphosphate bacteria, and provide a high-quality rapid internal carbon source for the subsequent removal of nitrogen and phosphorus, and the other part of the water is intended to remove COD. However, if the water volume of the two parts of water is not allocated reasonably, it is easy to cause a certain water quality indicator to exceed the standard. Therefore, it is necessary to establish a scientific adjustment method for the two water volumes so that the indicators of COD, total nitrogen (TN), ammonia nitrogen (NH3-N), and total phosphorus (TP) can meet the discharge standards without adding an external carbon source. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a method for adjusting water distribution in a liquor wastewater treatment process, which can scientifically distribute the water volume treated in different process sections without adding an external carbon source, and provide sufficient and moderate VFA that is easy to utilize for denitrifying bacteria and polyphosphate bacteria, thereby achieving COD, total nitrogen, ammonia nitrogen, and total phosphorus indicators that can meet emission standards.

[0004] The present invention provides a method for adjusting water distribution in a liquor wastewater treatment process. Figure 1 As shown, the following process is included:

[0005] a) The liquor wastewater is treated through a grille to obtain grille effluent;

[0006] b) a portion of the grid effluent enters a high-efficiency anaerobic treatment (UASB) reaction tank for treatment, and the other portion enters a hydrolysis acidification tank for treatment;

[0007] c) the effluent from the high-efficiency anaerobic treatment reaction tank and part of the effluent from the hydrolysis acidification tank enter the anaerobic tank for treatment;

[0008] d) another part of the effluent from the hydrolysis acidification tank and the effluent from the anaerobic tank enter the anoxic tank for treatment;

[0009] e) the effluent from the anoxic pool enters an aerobic pool for treatment;

[0010] f) a portion of the effluent from the aerobic tank is returned to the anoxic tank as nitrification liquid, and another portion of the effluent enters a sedimentation tank for mud-water separation;

[0011] g) a portion of the sludge separated in the sedimentation tank is returned to the anaerobic tank as return sludge, and another portion of the sludge is discharged as residual sludge; the effluent obtained by separation in the sedimentation tank is discharged;

[0012] The method for adjusting the water volume comprises the following steps:

[0013] S1) Determine the effluent TP (TP) of the high-efficiency anaerobic treatment reaction tank during the operation of the liquor wastewater treatment process UASB出水 ), VFA of the effluent from the high-efficiency anaerobic treatment reactor (VFA UASB出水 ), effluent TP of hydrolysis acidification tank (TP 水解酸化池出水 ), VFA (VFA) of the effluent from the hydrolysis acidification tank 水解酸化池出水 ) and the effluent VFA of the anaerobic tank (VFA 厌氧池出水 ) and the nitrate nitrogen content of the nitrification solution (NO3-N 硝化液 ); and determine the carbon-phosphorus ratio (R1) of the anaerobic tank sewage, the carbon-nitrogen ratio (R2) of the anoxic tank sewage and the return ratio (R3) of the nitrification solution;

[0014] S2) Substituting the measured and determined parameter values ​​into equations (1) to (3) to calculate k1, k3 and k4;

[0015]

[0016]

[0017] k1+k3+k4=1 (3);

[0018] In formula (1) to formula (3), the definitions of the symbols are as follows:

[0019] k1 is the coefficient of the ratio of the amount of water entering (flowing out) the high-efficiency anaerobic treatment reaction tank to the total amount of wastewater treatment, dimensionless;

[0020] k3 is the coefficient of the ratio of the amount of water from the hydrolysis acidification tank to the total amount of water for wastewater treatment, dimensionless;

[0021] k4 is the coefficient of the ratio of the amount of water from the hydrolysis acidification tank to the total amount of water treated by the anoxic tank, dimensionless;

[0022] R1 is the carbon-to-phosphorus ratio of anaerobic tank effluent, dimensionless;

[0023] R2 is the carbon-nitrogen ratio of the anoxic tank effluent, dimensionless;

[0024] R3 is the reflux ratio of the nitrifying solution, dimensionless;

[0025] TP 水解酸化池出水 is the effluent TP of the hydrolysis acidification tank, in mg / L;

[0026] VFA 水解酸化池出水 is the effluent VFA of the hydrolysis acidification tank, in mg / L;

[0027] TP UASB出水 It is the effluent TP of the high-efficiency anaerobic treatment reaction tank, in mg / L;

[0028] VFA UASB出水 It is the effluent VFA of the high-efficiency anaerobic treatment reactor, in mg / L;

[0029] VFA 厌氧池出水 is the effluent VFA of the anaerobic tank, in mg / L;

[0030] NO3-N 硝化液 is the nitric nitrogen content of the nitrification solution, in mg / L;

[0031] S3) According to the total water inflow (Q) of the grid and the calculated k1, k3 and k4, the amount of water entering (flowing out) the high-efficiency anaerobic treatment reaction tank (Q1), the amount of water flowing into the anaerobic tank from the effluent of the hydrolysis acidification tank (Q3) and the amount of water flowing into the anoxic tank from the effluent of the hydrolysis acidification tank (Q4) are calculated respectively, and the water distribution of the liquor wastewater treatment process is adjusted according to the calculated water volume results.

[0032] In the adjustment method provided by the present invention, formulas (1) to (2) are derived based on the following assumptions and calculation formulas:

[0033] 1) Considering that COD in nitrification solution is basically difficult to biodegrade compared with VFA, COD in nitrification solution is ignored when calculating carbon-nitrogen ratio;

[0034] 2) According to actual experience, after liquor wastewater is treated by UASB, hydrolysis acidification and anaerobic treatment, ammonia nitrogen accounts for the vast majority of total nitrogen in the effluent. Therefore, excluding nitrate nitrogen in the effluent of UASB, hydrolysis acidification and anaerobic tanks, the refluxed nitrification liquid is the only source of nitrate nitrogen in the anoxic tank;

[0035] 3) Considering that the focus of the present invention is to improve the treatment effect by using the easily degradable carbon source VFA, the carbon-nitrogen ratio is calculated according to the ratio of VFA to nitrate nitrogen, and the carbon-phosphorus ratio is calculated according to the ratio of VFA to total phosphorus;

[0036] 4) VFA is calculated based on acetic acid, and the COD equivalent per gram of acetic acid is 1.07 grams;

[0037] 5) Under the above conditions, the carbon-phosphorus ratio R1 of the anaerobic tank sewage and the carbon-nitrogen ratio R2 of the anoxic tank sewage are calculated. The calculation formulas are shown in formula (4) and formula (5) respectively:

[0038]

[0039]

[0040] 6) Based on equation (4), equation (5) and equation (3) provided above, equations (1) to (2) are derived.

[0041] In the adjustment method provided by the present invention, Figure 1 The meanings of some symbols in formula (1) to formula (5) are summarized and explained, as shown in Table 1:

[0042] Table 1 Summary of symbol meanings

[0043] symbol significance <![CDATA[R1 (Custom value)]]> Carbon-to-phosphorus ratio of anaerobic tank wastewater <![CDATA[R2 (Custom value)]]> Carbon-nitrogen ratio of effluent from anoxic pools <![CDATA[R3 (Custom value)]]> Reflux ratio of nitrification solution <![CDATA[k1 (value to be evaluated)]]> The ratio coefficient of the amount of water entering (flowing out) the UASB reaction pool to the total amount of water Q <![CDATA[k3 (value to be evaluated)]]> The ratio coefficient of the amount of water flowing into the anaerobic tank from the hydrolysis acidification tank to the total water volume Q <![CDATA[k4 (value to be evaluated)]]> The ratio coefficient of the amount of water flowing into the anoxic tank from the hydrolysis acidification tank to the total water volume Q Q <![CDATA[Total water inflow through the grille (m 3 / h)]]> <![CDATA[Q1]]> <![CDATA[The water volume entering (flowing out) the UASB reactor (m 3 / h, Q1 = k1Q)]]> <![CDATA[Q2]]> <![CDATA[The water volume entering the hydrolysis acidification tank (m 3 / h, Q2 = Q - Q1)]]> <![CDATA[Q3]]> <![CDATA[The water volume flowing from the hydrolysis acidification tank effluent into the anaerobic tank (m 3 / h, Q3 = k3Q)]]> <![CDATA[Q4]]> <![CDATA[The water volume flowing from the hydrolysis acidification tank into the anoxic tank (m 3 / h, Q4 = k4Q)]]> <![CDATA[Q5]]> <![CDATA[The water volume of the nitrified liquid flowing back from the aerobic tank to the anoxic tank (m 3 / h, Q5 = R3Q)]]>

[0044] In the adjustment method provided by the present invention, the carbon-to-phosphorus ratio (R1) of the anaerobic tank wastewater is preferably 15-25, specifically 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25.

[0045] In the adjustment method provided by the present invention, the carbon-nitrogen ratio (R2) of the anoxic tank wastewater is preferably 4 to 10, specifically 4, 5, 6, 7, 8, 9 or 10.

[0046] In the adjustment method provided by the present invention, the reflux ratio (R3) of the nitrating solution is preferably 1 to 5, specifically 1, 2, 3, 4 or 5.

[0047] Compared with the prior art, the present invention provides a method for adjusting water distribution in a liquor wastewater treatment process, comprising the following steps: determining the effluent TP of a UASB reaction tank, the effluent VFA of a UASB reaction tank, the effluent TP of a hydrolysis acidification tank, the effluent VFA of a hydrolysis acidification tank, the effluent VFA of an anaerobic tank and the nitrate-nitrogen content of a nitrification liquid under current operating conditions, and determining the carbon-phosphorus ratio R1 of the anaerobic tank sewage, the carbon-nitrogen ratio R2 of the anoxic tank sewage and the reflux ratio R3 of the nitrification liquid; substituting the determined and determined parameter values ​​into equations (1) to (3) to calculate k1, k3 and k4; according to the total water inflow Q of the grid and the calculated k1, k3 and k4, respectively calculating the amount of water entering the high-efficiency anaerobic treatment reaction tank, the amount of water flowing from the effluent of the hydrolysis acidification tank into the anaerobic tank and the amount of water flowing from the effluent of the hydrolysis acidification tank into the anoxic tank, and adjusting the water distribution of the liquor wastewater treatment process according to the calculated water amount results. The adjustment method involved in the present invention can scientifically distribute the amount of water treated in different process sections without adding an external carbon source, provide sufficient and not excessive VFA that is easy to utilize for denitrifying bacteria and polyphosphate bacteria, thereby achieving economical and efficient removal of pollutants such as COD, total nitrogen, ammonia nitrogen, and total phosphorus in wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0049] Figure 1 The present invention provides a flowchart of a liquor wastewater treatment process. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Example 1

[0052] A liquor wastewater comprehensive treatment plant adopts Figure 1 The treatment is carried out according to the process flow shown in the figure, and the emission standards are shown in Table 2.

[0053] Table 2 Fermentation alcohol and liquor industry water pollutant emission standards (GB27631-2011) (unit: mg / L)

[0054] Water quality indicators <![CDATA[COD cr ]]> <![CDATA[NH3-N]]> TN TP Indirect Emission Standards 400 30 50 3 Direct Emission Standards 100 10 20 1

[0055] The current water distribution ratio is: the water ratio entering (flowing out) the UASB reaction tank is k1=84%, the water ratio of the hydrolysis acidification tank effluent flowing into the anaerobic tank is k3=10%, and the water ratio of the hydrolysis acidification tank effluent flowing into the anoxic tank is k4=6%.

[0056] During the wastewater treatment process, the operating parameters of the hydrolysis acidification tank were: hydraulic retention time of 4.3 h, rising flow rate of 1.1 m / h, redox potential of -124 mV, pH = 6.2; the operating parameters of the UASB reaction tank were: rising flow rate of 0.5 m / h, redox potential of -272 mV, pH = 7.1, temperature of 26 ° C, volumetric load of 6.7 kg COD / (m 3 ·d); The operating parameters of the anaerobic tank are: hydraulic retention time of 2.2h, dissolved oxygen of 0.1mg / L; the operating parameters of the anoxic tank are: hydraulic retention time of 2.4h, dissolved oxygen of 0.3mg / L; the operating parameters of the aerobic tank are: hydraulic retention time of 6.5h, dissolved oxygen of 3.4mg / L, and the nitrification liquid return ratio to the anoxic tank is 270%; the operating parameters of the sedimentation tank are: sludge return ratio of 85%; under this operating condition, the water quality of each treatment section is shown in Table 3:

[0057] Table 3 Water quality table of each process section before adjustment (unit: mg / L)

[0058] Raw water Hydrolysis acidification tank effluent UASB reactor effluent Anaerobic tank effluent Nitrate solution Total water output COD 18282 15667 3056 1137 - 119 TN 430 422 417 396 - 23.5 <![CDATA[NH3-N]]> 290 292 297 279 - 8.2 TP 93 68 80 101 - 5.1 VFA - 6177 311 332 - - <![CDATA[NO3-N]]> - - - - 31 -

[0059] It can be seen that under this operating condition, the total phosphorus content of the effluent does not meet the indirect discharge standard of water pollutants for fermentation alcohol and liquor industry (GB27631-2011); therefore, the water volume of each part is calculated and adjusted as follows:

[0060] Step 1: Determine the carbon-phosphorus ratio R1 (R1=20) of the anaerobic tank sewage, the carbon-nitrogen ratio R2 (R2=5) of the anoxic tank sewage, and the nitrification liquid return ratio R3 (R3=3);

[0061] Step 2: Substitute the corresponding values ​​in step 1 and Table 2 into equations (1) and (2) to obtain k1=79%, k4=2%. Substitute k1 and k4 into equation (3) to obtain k3=19%.

[0062]

[0063]

[0064] k1+k3+k4=1 (3);

[0065] Step 3: According to the calculated k1, k3 and k4, determine the amount of water entering (flowing out) the UASB reaction tank, the amount of water flowing into the anaerobic tank from the hydrolysis acidification tank, and the amount of water flowing into the anoxic tank from the hydrolysis acidification tank. After stable operation, the water quality of each treatment section is shown in Table 4:

[0066] Table 4 Water quality table of each process section after adjustment (unit: mg / L)

[0067] Raw water Hydrolysis acidification tank effluent UASB reactor effluent Anaerobic tank effluent Nitrate solution Total water output COD 19023 16635 2985 1366 - 116 TN 441 455 401 452 - 18.7 <![CDATA[NH3-N]]> 302 303 295 315 - 8.5 TP 96 91 68 89 - 2.5 VFA - 6721 286 411 - - <![CDATA[NO3-N]]> - - - - 34 -

[0068] It can be seen that when various water quality indicators of raw water have deteriorated compared with before adjustment, the allocated water volume is determined by the calculation method of the present invention. After treatment, without adding an external carbon source, efficient treatment of COD, total nitrogen, ammonia nitrogen, total phosphorus, etc. is achieved, and the indirect emission standard of water pollutants for fermentation alcohol and liquor industry (GB27631-2011) is achieved, and even the total nitrogen reaches the direct discharge standard.

[0069] It should be pointed out that due to the large differences in initial operating conditions in different application cases, the above steps may be a gradual and multiple adjustment process. If the target is not achieved, the carbon-phosphorus ratio R1 of the anaerobic tank wastewater, the carbon-nitrogen ratio R2 of the anoxic tank wastewater, and the nitrification liquid return ratio R3 can be adjusted and then calculated and adjusted. At the same time, the operating conditions need to be adjusted after the water volume is redistributed so that the following water quality indicators do not fluctuate too much: the effluent TP (TP UASB出水 ), UASB effluent VFA (VFA UASB出水 ), effluent TP of hydrolysis acidification tank (TP 水解酸化池出水 ), VFA (VFA) of the effluent from the hydrolysis acidification tank 水解酸化池出水 ), nitrate nitrogen (NO3-N 硝化液 ) and the effluent VFA of the anaerobic tank (VFA 厌氧池出水 ).

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for adjusting water distribution in a liquor wastewater treatment process, characterized in that: The liquor wastewater treatment process includes the following processes: a) The liquor wastewater is treated through a grille to obtain grille effluent; b) a portion of the grid effluent enters a high-efficiency anaerobic treatment reaction tank for treatment, and the other portion enters a hydrolysis acidification tank for treatment; c) the effluent from the high-efficiency anaerobic treatment reaction tank and part of the effluent from the hydrolysis acidification tank enter the anaerobic tank for treatment; d) another part of the effluent from the hydrolysis acidification tank and the effluent from the anaerobic tank enter the anoxic tank for treatment; e) the effluent from the anoxic pool enters an aerobic pool for treatment; f) a portion of the effluent from the aerobic tank is returned to the anoxic tank as nitrification liquid, and another portion of the effluent enters a sedimentation tank for mud-water separation; g) a portion of the sludge separated in the sedimentation tank is returned to the anaerobic tank as return sludge, and the other portion of the sludge is discharged as excess sludge; The sedimentation tank separates and obtains effluent for discharge; The method for adjusting the water distribution comprises the following steps: S1) Determine the effluent TP of the high-efficiency anaerobic treatment reaction tank, the effluent VFA of the high-efficiency anaerobic treatment reaction tank, the effluent TP of the hydrolysis acidification tank, the effluent VFA of the hydrolysis acidification tank, the effluent VFA of the anaerobic tank, and the nitrate-nitrogen content of the nitrification liquid during the operation of the liquor wastewater treatment process; and determine the carbon-phosphorus ratio of the anaerobic tank sewage, the carbon-nitrogen ratio of the anoxic tank sewage, and the reflux ratio of the nitrification liquid; S2) Substituting the measured and determined parameter values ​​into equations (1) to (3) to calculate k1, k3 and k4; k1+k3+k4=1 (3); In formula (1) to formula (3), the definitions of the symbols are as follows: k1 is the coefficient of the proportion of the water volume entering the high-efficiency anaerobic treatment reaction tank to the total water volume of wastewater treatment, dimensionless; k3 is the coefficient of the ratio of the amount of water from the hydrolysis acidification tank to the total amount of water for wastewater treatment, dimensionless; k4 is the coefficient of the ratio of the amount of water from the hydrolysis acidification tank to the total amount of water treated by the anoxic tank, dimensionless; R1 is the carbon-to-phosphorus ratio of anaerobic tank effluent, dimensionless; R2 is the carbon-nitrogen ratio of the anoxic tank effluent, dimensionless; R3 is the reflux ratio of the nitrifying solution, dimensionless; TP 水解酸化池出水 is the effluent TP of the hydrolysis acidification tank, in mg / L; VFA 水解酸化池出水 is the effluent VFA of the hydrolysis acidification tank, in mg / L; TP UASB出水 It is the effluent TP of the high-efficiency anaerobic treatment reaction tank, in mg / L; VFA UASB出水 It is the effluent VFA of the high-efficiency anaerobic treatment reactor, in mg / L; VFA 厌氧池出水 is the effluent VFA of the anaerobic tank, in mg / L; NO3-N 硝化液 is the nitric nitrogen content of the nitrification solution, in mg / L; S3) According to the total water inflow of the grid and the calculated k1, k3 and k4, the amount of water entering the high-efficiency anaerobic treatment reaction tank, the amount of water flowing into the anaerobic tank from the effluent of the hydrolysis acidification tank, and the amount of water flowing into the anoxic tank from the effluent of the hydrolysis acidification tank are calculated respectively, and the water distribution of the liquor wastewater treatment process is adjusted according to the calculated water volume results.

2. The adjustment method according to claim 1, characterized in that: The carbon-to-phosphorus ratio of the anaerobic tank wastewater is 15-25.

3. The adjustment method according to claim 1, characterized in that: The carbon-nitrogen ratio of the anoxic pool sewage is 4-10.

4. The adjustment method according to claim 1, characterized in that: The reflux ratio of the nitrifying solution is 1-5.

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