Method for determining nitrogen removal carbon source ratio of landfill leachate based on material balance

Abstract

The invention discloses a method for determining the nitrogen removal carbon source ratio of landfill leachate based on material balance, and relates to a method for determining the nitrogen removal carbon source ratio of the landfill leachate. The invention aims to solve the technical problems that the cost of supplementing a carbon source is high when the old landfill leachate is denitrified by adopting an MBR (Membrane Biological Reactor) mode at present, and the content of sulfate radicals and hardness can be increased when fresh landfill leachate is added as a carbon source, so that the pressure of subsequent deep treatment is increased. By analyzing the biodegradability of the supplemented carbon source and analyzing the effective carbon source to construct the material balance model, the problem of insufficient carbon sources in landfill leachate treatment is effectively solved, meanwhile, denitrification of the landfill leachate is realized to the greatest extent, the content of total ammonia nitrogen is greatly reduced, the carbon-nitrogen ratio is improved, and subsequent standard treatment is facilitated; and the optimal adding amount of the fresh landfill leachate is determined, so that the method has economical efficiency. The method provided by the invention has a good treatment effect on landfill leachate denitrification, and has a good guiding significance on the on-site landfill leachate treatment process.

Description

Technical Field

[0001] The invention relates to a method for determining the ratio of carbon sources for denitrification of landfill leachate. Background Art

[0002] The method of treating landfill leachate by sanitary landfill has the advantages of simple operation, low cost and convenient treatment. It is currently the most widely used method in China. However, sanitary landfill is not the best method of waste treatment. The landfill leachate produced in the process of sanitary landfill is a high-concentration sewage with high chroma, complex composition, large water quality changes and foul odor. It contains a large amount of pollutants such as ammonia nitrogen and COD. With the increase of landfill years and the action of microorganisms, the organic matter content of late landfill leachate will decrease, the carbon-nitrogen ratio will be unbalanced, and the biodegradability will deteriorate; therefore, it is particularly important and challenging to denitrify landfill leachate.

[0003] The landfill time of old landfill leachate is long and its biodegradability is poor. In view of the high ammonia nitrogen and serious imbalance of carbon-nitrogen ratio of old landfill leachate, at present, the landfill mainly uses MBR to denitrify landfill leachate, in which the biochemical unit adopts nitrification and denitrification. However, this process requires sufficient carbon source. Insufficient carbon source will lead to poor effluent effect, so it is necessary to add external carbon source for adjustment. According to the traditional method, the denitrification effect will be improved by adding glucose reagent, but at the same time it will bring huge economic pressure. Fresh landfill leachate has better biodegradability, and there are more effective carbon sources for nitrification and denitrification process. However, the addition of fresh landfill leachate as a carbon source will increase its sulfate and hardness content while improving the carbon-nitrogen ratio of old landfill leachate, resulting in increased pressure for subsequent deep treatment. Therefore, it is feasible to add fresh landfill leachate as a carbon source supplement, among which the addition ratio is the most important link. It is necessary to make a suitable ratio of carbon source supplement in old landfill leachate to reduce the treatment cost without affecting the subsequent deep treatment. Summary of the invention

[0004] The present invention aims to solve the technical problems that the cost of supplementing carbon sources is high when denitrifying old landfill leachate using MBR, and the addition of fresh landfill leachate as a carbon source will increase the sulfate and hardness content, leading to increased pressure in subsequent deep treatment, and provides a method for determining the carbon source ratio for denitrification of landfill leachate based on material balance.

[0005] The method for determining the carbon source ratio of landfill leachate denitrification based on material balance of the present invention is carried out according to the following steps:

[0006] The test results show that the ammonia nitrogen value of old landfill leachate is A, the biodegradable COD value is B, and the hardness is F; the ammonia nitrogen value of fresh landfill leachate is C, the biodegradable COD value is D, and the hardness is G; the biodegradable COD value of glucose is E; the units of the above seven values ​​are all mg / L;

[0007] Fresh landfill leachate and glucose are added to the old landfill leachate as carbon sources to perform denitrification in an MBR manner, wherein the biochemical unit adopts a nitrification and denitrification manner; the volume ratio of the old landfill leachate, fresh landfill leachate and glucose is 100:m:n, and m and n must simultaneously satisfy the following formula 1 and formula 2:

[0008] (100×B+m×D+n×E) / (100+m+n)=H;

[0009] (100×A+m×C) / (100+m+n)=I;

[0010] 4.97≤H / I≤9.87 (1);

[0011] Where H is the biodegradable COD value after mixing, and I is the ammonia nitrogen value after mixing;

[0012] (100×F+m×G) / (100+m+n)<1000 (2).

[0013] The present invention has the following beneficial effects:

[0014] The present invention analyzes the biodegradability of the supplementary carbon source by comparing and analyzing the effective carbon source to construct a material balance model, effectively solves the problem of insufficient carbon source in the on-site process treatment of landfill leachate, and at the same time realizes the denitrification of landfill leachate to the greatest extent, greatly reduces the content of ammonia nitrogen and total nitrogen, improves the carbon-nitrogen ratio, and is conducive to subsequent standard-reaching treatment; and determines the optimal addition ratio of fresh landfill leachate, which is economical. Therefore, the present invention has good treatment effect and economic benefits in the denitrification of landfill leachate, and has good guiding significance for the on-site treatment of landfill leachate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the COD test diagram of the old garbage leachate in Experiment 1;

[0016] Figure 2 This is the COD test chart of fresh landfill leachate in Experiment 1;

[0017] Figure 3 This is the COD test graph of glucose in Experiment 1;

[0018] Figure 4 This is the test chart of the proportion of effective carbon sources in Experiment 1;

[0019] Figure 5 This is the test chart of TN and ammonia nitrogen in the effluent of a small-scale experiment;

[0020] Figure 6 This is a test chart of sulfate, hardness and COD in the effluent of a small-scale experiment;

[0021] Figure 7 This is the test chart of pH and conductivity in the effluent of a small-scale experiment;

[0022] Figure 8 This is the process flow chart for the pilot test in Experiment 1;

[0023] Fig. 9 This is the test chart of ammonia nitrogen and total nitrogen in the influent and effluent during the on-site production operation in Test 1;

[0024] Fig.10 This is the COD test chart of the influent and effluent during the on-site production operation in Test 1;

[0025] Fig.11 This is the sulfate test diagram of the influent and effluent during the on-site production operation in Test 1;

[0026] Fig.12 This is the hardness test diagram of the inlet and outlet water during the on-site production operation in Test 1;

[0027] Fig.13 This is the conductivity test diagram of the inlet and outlet water during the on-site production operation in Test 1;

[0028] Fig.14 This is the pH test diagram of the inlet and outlet water during the on-site production operation in Experiment 1;

[0029] Fig.15 This is the test chart of TN and ammonia nitrogen in the effluent of the small-scale experiment in Experiment 2;

[0030] Fig.16 This is the test chart of sulfate, hardness and COD in the effluent from the small-scale experiment of Experiment 2. DETAILED DESCRIPTION

[0031] Specific implementation method 1: This implementation method is a method for determining the carbon source ratio for denitrification of landfill leachate based on material balance, which is specifically carried out in the following steps:

[0032] The test results show that the ammonia nitrogen value of old landfill leachate is A, the biodegradable COD value is B, and the hardness is F; the ammonia nitrogen value of fresh landfill leachate is C, the biodegradable COD value is D, and the hardness is G; the biodegradable COD value of glucose is E; the units of the above seven values ​​are all mg / L;

[0033] Fresh landfill leachate and glucose are added to the old landfill leachate as carbon sources to perform denitrification in an MBR manner, wherein the biochemical unit adopts a nitrification and denitrification manner; the volume ratio of the old landfill leachate, fresh landfill leachate and glucose is 100:m:n, and m and n must simultaneously satisfy the following formula 1 and formula 2:

[0034] (100×B+m×D+n×E) / (100+m+n)=H;

[0035] (100×A+m×C) / (100+m+n)=I;

[0036] 4.97≤H / I≤9.87 (1);

[0037] Where H is the biodegradable COD value after mixing, and I is the ammonia nitrogen value after mixing;

[0038] (100×F+m×G) / (100+m+n)<1000 (2).

[0039] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that the ammonia nitrogen value is determined by using Nessler's reagent spectrophotometry. The rest is the same as the specific implementation method 1.

[0040] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that the biochemical COD value is tested by a shake bottle experiment. The rest is the same as specific implementation method 1 or 2.

[0041] Specific embodiment 4: This embodiment is different from specific embodiments 1 to 3 in that the hardness is measured by EDTA titration method. The rest is the same as specific embodiments 1 to 3.

[0042] Specific implementation method 5: This implementation method is different from the specific implementation method 4 in that: Formula 1 is obtained based on the following formula:

[0043] △COD / △N=2.86 / (1-1.42Y b );

[0044] Where: △COD is the COD involved in denitrification reaction, unit is mg / L;

[0045] △N is the nitric nitrogen involved in denitrification, in mg / L;

[0046] Y b is the apparent yield of sludge of denitrifying bacteria, specifically 0.3 to 0.5. The rest is the same as the fourth embodiment.

[0047] The present invention is verified by the following tests:

[0048] Test 1: This test is a method for determining the carbon source ratio for denitrification of landfill leachate based on material balance, which is specifically carried out in the following steps:

[0049] The aged leachate from the landfill of Jiangxi Dingyuan Ecological Environmental Protection Co., Ltd. has insufficient carbon sources. Material balance and carbon source supplementation analysis are now being conducted. The specific implementation steps are as follows:

[0050] 1) Determination of physical and chemical properties of old and fresh landfill leachate: The determination indicators and methods are as follows:

[0051] COD was determined by rapid elimination spectrophotometry (HJ / T 399-2007);

[0052] Ammonia nitrogen was determined by Nessler's reagent spectrophotometry;

[0053] Total nitrogen was determined by UV spectrophotometry with alkaline potassium persulfate digestion;

[0054] Hardness is measured by EDTA titration method (GB7477-87);

[0055] Sulfate was determined using the SulfaVer4 method;

[0056] The measurement results are shown in Table 1 below:

[0057] Table 1 Water quality indicators of landfill leachate

[0058] Leachate from aged landfill Fresh landfill leachate Total nitrogen TN (mg / L) 1720 2170 Ammonia nitrogen (mg / L) 1600 1800 Sulfate (mg / L) 800 670 Hardness(mg / L) 500 6000 COD(mg / L) 1374 49880

[0059] The effective carbon source was analyzed by shaking flask experiment. The shaking flask experiment was based on the BOD5 standard test method to detect the biodegradable COD in the two water samples. Figure 1-Figure 4 And Table 2, Figure 1 COD of old landfill leachate, Figure 2 is the COD of fresh landfill leachate, Figure 3 COD of glucose, Figure 4 The results show that the effective carbon source ratio of fresh landfill leachate and glucose carbon source is more than 80%, while that of old landfill leachate is only 29%; fresh landfill leachate and purchased carbon source glucose have the same effective carbon source.

[0060] Table 2 Biodegradability Experimental Data

[0061]

[0062] 0.29 is (1374-982) / 1374;

[0063] Establishment of material balance model: The denitrification treatment of landfill leachate mainly adopts nitrification and denitrification. Based on this, material balance is carried out while considering anabolism.

[0064] Nitrification and denitrification process: The nitrification process uses CO2 and CO3 2- 、HCO3 - As carbon sources, the denitrification process uses organic matter as a carbon source to provide electron donors and energy; the material balance analysis is as follows: 1g of cell matter is equivalent to 1.42g of COD, so denitrifying bacteria need to consume 1.42g of COD to synthesize 1g of cell matter; after considering the energy source of denitrifying bacteria and their own growth and reproduction, the following formula can be obtained:

[0065] △COD / △N=2.86 / (1-1.42Y b );

[0066] Where: △COD——COD involved in denitrification reaction, unit is mg / L;

[0067] △N——Nitric nitrogen involved in denitrification reaction, in mg / L;

[0068] Y b ——The apparent sludge yield of denitrifying bacteria (remember that it is the sludge yield of denitrifying bacteria rather than the sludge yield of the entire system, which is 0.3-0.5;

[0069] 2.86: The amount of carbon source consumed to reduce 1g of nitrate.

[0070] 1.42: COD amount contributed by the cell body;

[0071] In summary, it can be analyzed that the coefficient ratio of nitrogen removal and carbon source supplementation is at least 1:2.86, and the linear regression equation is constructed:

[0072] C 总 =2.86(N-N0) / (1-1.42Y b );

[0073] Where: C 总 : Total amount of effective carbon source in influent; mg / L

[0074] N: Nitrogen content in influent; mg / L

[0075] N0: Nitrogen content in the effluent from the MBR system; mg / L;

[0076] Because Y b is the apparent yield of denitrifying bacteria in sludge, which is 0.3-0.5. b The minimum value (0.3), maximum value (0.5) and middle value (0.4) are used for ratio analysis:

[0077] Table 3Y b Corresponding C / N value

[0078] <![CDATA[Y b ]]> C / N 0.3 4.98 0.4 6.62 0.5 9.86

[0079] Table 4 Analysis of the optimal ratio of old and fresh landfill leachate

[0080]

[0081] Note: The three mixing ratios in the table are the volume ratios of old landfill leachate: fresh landfill leachate: glucose;

[0082] 1598 = (1800 × 7 + 1600 × 10) / 108; 4.99 = 7971 / 1598;

[0083] The optimal ratio model range constructed is that the volume ratio of old: fresh: carbon source is = 100:7:1 ~ 100:43:1. Within this ratio range, the carbon source required for the denitrification process can be met.

[0084] Table 5 Hardness analysis under different dosage ratios

[0085]

[0086] 991=(500×100+6000×10) / 111;

[0087] Note: The effluent from the MBR system must have a hardness of <1000mg / L;

[0088] Note: The proportions in the table are the volume ratios of old landfill leachate: fresh landfill leachate: glucose;

[0089] The selection of 100:10:1 is based on the fact that the hardness is close to Y when it is less than 1000 mg / L. b =0.4 is the best.

[0090] Under the condition that the effective carbon source meets the optimal carbon-nitrogen ratio, the sulfate and hardness in the effluent water quality should not be too high to avoid affecting the subsequent deep treatment, that is, the hardness should be <1000mg / L;

[0091] The dosage of fresh landfill leachate will affect the sulfate content in the effluent. Based on the ratio constructed above (100:7:1-100:43:1), the ratio analysis is carried out according to the sulfate and hardness thresholds. The dosage of fresh landfill leachate puts great pressure on the subsequent deep treatment. At the same time, due to the limitation of the total amount of old landfill leachate treated in the on-site operation, the proportion of fresh landfill leachate in the constructed model will affect the treatment volume of old landfill leachate. Under the condition of full load operation on site, the theoretical model ratio cannot be reached. Therefore, the dosage of fresh landfill leachate needs to be reduced accordingly. It can be seen from Table 5 that the volume ratio of old: fresh: glucose = 100:10:1 is selected for the experiment. Theoretically calculated C / N is 5.7 under this ratio, which is within the theoretical ratio range, and the hardness content is 991 mg / L, which meets the effluent requirements. Based on this, the amount of fresh landfill leachate added is reduced, and sulfate and hardness decrease accordingly, meeting the requirements of subsequent deep treatment.

[0092] Small-scale experimental operation: Based on the establishment of the above-mentioned material balance model and the actual situation on site, the volume ratio of old garbage leachate: fresh garbage leachate: glucose was 100:10:1. By simulating the two-stage AO treatment process of the landfill, the carbon source addition ratio was determined on the basis of the construction of the material balance model, and the treatment effect of the old garbage leachate after the carbon source was supplemented was analyzed; the process is as follows Figure 8 As shown: Carbon source is added in a proportion in the equalization tank, and the effluent from the equalization tank enters a two-stage AO treatment system, where the hydraulic retention time is 10 days, the sludge concentration in the AO tank is 8000 mg / L, the return ratio from the O tank to the A tank is 1:30, and finally the mud and water are separated in the sedimentation tank; the effluent data obtained are as follows Figure 5-Figure 7 And Table 6, Figure 5 For TN and ammonia nitrogen in the effluent, Figure 6 For sulfate, hardness and COD in the effluent, Figure 7 is the pH and conductivity of the effluent;

[0093] Table 6 Experimental inlet and outlet water quality

[0094]

[0095] On the basis of the above-mentioned ratio of carbon source supplementation, the effluent data shows that when the volume ratio of old landfill leachate: fresh landfill leachate: glucose is 100:10:1, the pH value remains relatively stable during the experiment, and the indicators such as effluent ammonia nitrogen and total nitrogen all achieve ideal operating results. At the same time, the sulfate and hardness of the effluent are significantly reduced, meeting the water inlet requirements of the subsequent deep treatment membrane system, and the effluent trial operation achieves the expected results.

[0096] On-site production operation: mixed ratio addition analysis (volume ratio of old landfill leachate: fresh landfill leachate: glucose is 100:10:1), data see Figure 9-14 And Table 7, Fig. 9 The data for ammonia nitrogen and total nitrogen are Fig.10 For COD, Fig.11 is sulfate, Fig.12 is the hardness, Fig.13 is the conductivity, Fig.14 is pH.

[0097] Table 7 On-site operation inlet and outlet water quality table

[0098] parameter Average water intake Average water output Removal rate pH 7.62 7.42 / Ammonia nitrogen 1455.54mg / L 17.18mg / L 98.82％ COD 5402.87mg / L 853.15mg / L 84.21％ Total Nitrogen / 74.87mg / L / Conductivity 18751.74μs / cm 11003.91μs / cm 41.32％ Sulfate 554.35mg / L 583.04mg / L -5.18％ hardness 1120.65mg / L 1168.48mg / L -4.27％

[0099] When fresh landfill leachate is mixed with glucose as a carbon source, the overall water quality is alkaline in both inlet and outlet water, with little change. The ammonia nitrogen removal rate reaches 98.82%, and the average effluent ammonia nitrogen after biochemical treatment is 17.18 mg / L. The total nitrogen effluent concentration is 74.87 mg / L. In the denitrification stage, nitrates are fully reduced and removed from the water. The influent COD reaches 5402.87 mg / L, and after 84.21% is effectively removed, the COD is reduced to 853.15 mg / L, which indicates that organic matter is effectively degraded by microorganisms in the aerobic stage. The conductivity is reduced by 41.32% after biochemical treatment. Due to the high hardness and sulfate of fresh landfill leachate, the effluent hardness and sulfate increased by 4.27% and 5.18% respectively. The hardness removal rate is the lowest, which indicates that calcium, magnesium and other ions in water that cause hardness are difficult to remove in the biochemical process.

[0100] Experiment 2: Aiming at the problem of insufficient carbon source in the anaerobic digestate treatment of food waste of Jiangxi Dingyuan Ecological Environmental Protection Co., Ltd., a material balance and carbon source analysis was conducted. The specific implementation steps are as follows, and the calculation process is the same as that of Experiment 1:

[0101] 1) Determination of physical and chemical properties of anaerobic digestate from food waste

[0102] Table 8 Water quality indicators of water samples

[0103] Anaerobic digestion of food waste Fresh landfill leachate TN(mg / L) 2532.42 2170 Ammonia nitrogen (mg / L) 2205.73 1800 Sulfate (mg / L) 950 670 Hardness(mg / L) 100 6000 COD(mg / L) 1643 59797

[0104] 2) The effective carbon source was analyzed by shake flask experiment, and the biodegradable COD in the two water samples was tested. The shake flask experiment results (such as Table 9) showed that the effective carbon source ratio of fresh landfill leachate and glucose carbon source was more than 80%, while that of anaerobic digestate from food waste was only 48%. Fresh landfill leachate and purchased carbon source had the same effective carbon source. The model was constructed based on the biodegradable COD, and the optimal ratio was determined while meeting the on-site operating conditions and MBR effluent requirements.

[0105] Table 9 Biodegradability Experimental Data Table

[0106]

[0107] 3) Material balance and model establishment: According to the results of the shake bottle experiment, the effective carbon sources of the two water samples were analyzed, and the optimal ratio and carbon source dosage were determined according to the carbon source addition model and the hardness threshold; Consider the material balance and model establishment of synthetic metabolism:

[0108] C 总 =2.86(NN 0) / (1-1.42Y b )

[0109] Table 10Y b Corresponding C / N value

[0110] <![CDATA[Y b ]]> C / N 0.3 4.98 0.4 6.62 0.5 9.86

[0111] Table 11 Analysis of the optimal ratio of anaerobic biogas slurry from food waste to fresh landfill leachate

[0112]

[0113] Note: The three ratios in the table are the volume ratios of anaerobic digestate from food waste: fresh leachate: glucose;

[0114] The optimal ratio model constructed is that the volume ratio of anaerobic digestate from food waste: fresh leachate: glucose is 100:15:1 to 100:68:1. Within this ratio range, the carbon source required for the denitrification process can be met.

[0115] Table 12 Hardness analysis under different dosage ratios

[0116]

[0117] Under the condition that the effective carbon source meets the optimal carbon-nitrogen ratio, the hardness of the effluent water quality cannot be too high to avoid affecting the subsequent deep treatment, that is, the hardness is <1000mg / L. The amount of fresh landfill leachate added will affect the hardness content of the effluent. Based on the above-mentioned ratio range of restaurant biogas slurry: fresh: carbon source, the ratio analysis is performed according to the hardness threshold. The amount of fresh landfill leachate added will cause great pressure on the subsequent deep treatment; at the same time, due to the total amount of old landfill leachate treated on-site, the proportion of fresh landfill leachate in the constructed model will affect The treatment capacity of anaerobic digestate and leachate from food waste cannot reach the theoretical model ratio when it is operated at full capacity on site; therefore, the amount of fresh leachate added needs to be reduced accordingly, that is, the volume ratio of anaerobic digestate from food waste: fresh leachate: glucose is 100:18:1 for a small-scale experiment. Theoretically calculated, the C / N ratio is 5.41 under this ratio, which is not much different from the theoretically required C / N. Based on this, the amount of fresh leachate added is reduced, and the sulfate and hardness decrease accordingly, meeting the subsequent deep treatment requirements.

[0118] 4) Small-scale experimental operation. Based on the establishment of the above-mentioned material balance model and the actual situation on site, the small-scale experiment was carried out with the volume ratio of anaerobic digestate of restaurant waste: fresh landfill leachate: glucose being 100:18:1. The effluent data obtained are as follows: Fig.15 , Fig.16 As shown in Table 13, Fig.15 TN and ammonia nitrogen, Fig.16 For sulfate, hardness and COD.

[0119] The selection of 100:18:1 is based on the hardness <1000mg / L close to Y b =0.4 is the best.

[0120] Table 13 Small-scale experimental inlet and outlet water quality and operating conditions

[0121]

[0122] On the basis of the above-mentioned ratio of carbon source supplementation, the small-scale test effluent data obtained can be concluded that a small-scale experiment was carried out at a volume ratio of 100:18:1 of anaerobic digestate from food waste: fresh leachate: glucose. The pH value remained relatively stable during the experiment, and indicators such as effluent ammonia nitrogen and total nitrogen achieved ideal operating results. At the same time, the sulfate and hardness of the effluent were significantly reduced, meeting the water inlet requirements of the subsequent deep treatment membrane system, and the effluent small-scale trial operation achieved the expected results.

Claims

1. A method for determining the ratio of carbon source for denitrification of landfill leachate based on material balance, characterized in that The method for determining the carbon source ratio for denitrification of landfill leachate based on material balance is carried out in the following steps: The test results show that the ammonia nitrogen value of old landfill leachate is A, the biodegradable COD value is B, and the hardness is F; the ammonia nitrogen value of fresh landfill leachate is C, the biodegradable COD value is D, and the hardness is G; The biochemical COD value of glucose is E; the units of the above seven values ​​are all mg / L; Fresh landfill leachate and glucose are added to the old landfill leachate as carbon sources to perform denitrification in an MBR manner, wherein the biochemical unit adopts a nitrification and denitrification manner; the volume ratio of the old landfill leachate, fresh landfill leachate and glucose is 100:m:n, and m and n must simultaneously satisfy the following formula 1 and formula 2: (100×B+m×D+n×E) / (100+m+n)=H; (100×A+m×C) / (100+m+n)=I; 4.97≤H / I≤9.87 (1); Where H is the biodegradable COD value after mixing, and I is the ammonia nitrogen value after mixing; (100×F+m×G) / (100+m+n)<1000(2).

2. The method for determining the ratio of carbon source for denitrification of landfill leachate based on material balance according to claim 1, characterized in that Ammonia nitrogen value was determined by Nessler's reagent spectrophotometry.

3. The method for determining the ratio of carbon source for denitrification of landfill leachate based on material balance according to claim 1, characterized in that The biochemical COD value was tested by shake flask experiment.

4. The method for determining the carbon source ratio for denitrification of landfill leachate based on material balance according to claim 1, characterized in that Hardness was determined by EDTA titration.

5. The method for determining the ratio of carbon source for denitrification of landfill leachate based on material balance according to claim 1, characterized in that Formula 1 is obtained based on the following formula: △COD / △N=2.86 / (1-1.42Y b ); Where: △COD is the COD involved in denitrification reaction, unit is mg / L; △N is the nitric nitrogen involved in denitrification, in mg / L; Y b is the apparent yield of sludge of denitrifying bacteria, specifically 0.3 to 0.5.

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