Percolate biochemical treatment process

Abstract

The invention discloses a biochemical treatment process for leachate. The biochemical treatment process comprises the following steps: S01, adjusting the pH value of the leachate to 7-9, then introducing the leachate into a biochemical reaction tank, and adding aerobic bacteria into the reaction tank for carrying out microbial metabolism on the leachate; s02, the leachate in the biochemical reaction tank is introduced into an aeration tank for standing for a period of time, the pH value is adjusted to 7.3-8.0, and the dissolved oxygen concentration after aeration is 2-8 mg / L; s03, the aerated leachate is introduced into a sedimentation tank for standing treatment, and suspended solids in the leachate are removed; s04, the leachate in the sedimentation tank is introduced into a deep treatment tank, activated carbon, a PAM solution and a PAC solution are added for stirring treatment, standing is conducted for a period of time, and finally effluent is obtained. Through cooperation of the steps, the contents of ammonia nitrogen, chemical oxygen demand and the like in the leachate are effectively reduced, the treatment efficiency and stability of the leachate are improved, and the treatment cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of leachate treatment, and in particular relates to a leachate biochemical treatment process. Background Art

[0002] Leachate refers to a special type of waste liquid that usually contains hazardous and toxic substances and may pose a serious threat to the environment and human health. It usually comes from facilities that treat hazardous waste, such as hazardous waste landfills. When these facilities treat waste, the water in the waste will seep into the soil and groundwater to form leachate. This leachate may contain harmful chemicals such as heavy metals, COD, organic matter, ammonia nitrogen and toxic chemicals, which will cause serious harm to the environment and human health if not properly treated and discharged.

[0003] At present, the commonly used method for treating ammonia nitrogen in leachate is double evaporation. However, this treatment method consumes a lot of electricity and has high reagent costs, and the treatment effect is not obvious. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a biochemical treatment process for leachate, which aims to solve the technical problem that the existing ammonia nitrogen removal effect in leachate is poor.

[0005] To achieve the above object, the present invention provides the following technical solution: a leachate biochemical treatment process, comprising:

[0006] S01: After adjusting the pH value of the leachate to 7-9, the leachate is then introduced into a biochemical reaction tank, and aerobic bacteria are added to the reaction tank to perform microbial metabolism on the leachate;

[0007] S02: The leachate in the biochemical reaction tank is introduced into the aeration tank and allowed to stand for a period of time, the pH value is adjusted to 7.3-8.0, and the dissolved oxygen concentration after aeration is 2-8 mg / L;

[0008] S03: introducing the aerated leachate into a sedimentation tank for static treatment to remove suspended matter in the leachate;

[0009] S04: The leachate in the sedimentation tank is introduced into the deep treatment tank, and activated carbon, PAM solution, and PAC solution are added for stirring treatment, and the mixture is allowed to stand for a period of time to finally obtain effluent.

[0010] Furthermore, the dissolved oxygen concentration in the reaction tank is 2-5 mg / L.

[0011] Furthermore, the aerobic bacteria is any one of nitrifying bacteria, denitrifying bacteria, Bacillus, Pseudomonas, Steinernea, and Aerobacterium fluorescens.

[0012] Furthermore, the step S01 further includes:

[0013] The leachate is introduced into the regulating pond and mixed with rainwater to adjust the pH value of the leachate to 7-9; and the chemical oxygen demand in the leachate is 200-500 mg / L, the ammonia nitrogen content is 40-90 mg / L, and the chloride ion content is 8000-20000 mg / L.

[0014] Further, the step SO2 comprises:

[0015] A: Introduce the leachate from the biochemical reaction tank into the first aeration tank, adjust the pH value to 7.3-8.0, and the dissolved oxygen to 2-4 mg / L;

[0016] B: When the sludge volume content in the first aeration tank is 15%-25%, the leachate is introduced into the second aeration tank and the pH value is adjusted to 7.3-8.0 and the dissolved oxygen is 4-6 mg / L;

[0017] C: When the sludge concentration in the second aeration tank is 15%-25%, the leachate is introduced into the third aeration tank and the pH value is adjusted to 7.3-8.0 and the dissolved oxygen is 4-7 mg / L;

[0018] D: When the sludge concentration in the third aeration tank is 9%-15%, the leachate is introduced into the sedimentation tank for static treatment.

[0019] Furthermore, the standing time in the sedimentation tank is 9-12 hours.

[0020] Furthermore, the step S04 includes: introducing the leachate in the sedimentation tank into the deep treatment tank, controlling the frequency of the activated carbon feeder to 5-50HZ, adding activated carbon to the leachate, and when the chemical oxygen content in the leachate is ≤35mg / L, the activated carbon feeder stops feeding.

[0021] Furthermore, the mass concentration of the PAC is 0.1-0.45 Kg / m 3 .

[0022] Furthermore, the mass concentration of the PAM is 0.003-0.02 Kg / m 3 .

[0023] The beneficial effects of the present invention are as follows: compared with the prior art, a biochemical treatment process for leachate in the present invention introduces leachate into a biochemical reaction tank and adds aerobic bacteria into the reaction tank, so that soluble organic matter in the leachate can be absorbed into the bacteria through the cell wall and cell membrane of the aerobic bacteria; at the same time, colloids and suspended organic matter in the leachate are adsorbed on the surface of the aerobic bacteria, decomposed into soluble substances by the exoenzymes of the aerobic bacteria, and then enter the bacteria. In the bacteria, these organic substances are oxidized and degraded through the decomposition and metabolism process, and the energy released meets the needs of bacterial life activities; some of the oxidation intermediates form new cell substances through anabolism, promote the growth and reproduction of bacteria, and the final treatment product is a stable inorganic substance, which realizes the harmless treatment of leachate; by introducing the leachate into the aeration tank, the sludge in the leachate can be settled; by introducing the leachate in the aeration tank into the sedimentation tank, the suspended matter in the water is effectively removed by standing in the sedimentation tank, the water flow rate is reduced, and the water quality is purified; by adding activated carbon, PAM solution, and PAC solution in the deep treatment tank for stirring treatment, the organic matter, odor, pigment and other impurities in the water are effectively removed by the added activated carbon powder; by adding PAM solution and PAC solution, the suspended particles in the leachate are aggregated into larger floccules, the sedimentation is accelerated, the solid-liquid separation efficiency is improved, and the effect of purifying water quality is further achieved. Through the coordinated cooperation of each step in the present application, the content of ammonia nitrogen, chemical oxygen demand, etc. in the leachate is effectively reduced, the efficiency and stability of leachate treatment are improved, and the disposal cost is reduced.

[0024] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art may be taught from the practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration:

[0026] Figure 1 The present invention is a flowchart of a biochemical treatment process for leachate according to an embodiment of the present invention.

[0027] Figure 2 A comparison diagram before and after COD removal in leachate is provided for one embodiment of the present invention;

[0028] Figure 3 A comparison diagram of ammonia nitrogen before and after the removal of ammonia nitrogen in leachate is provided for one embodiment of the present invention;

[0029] Figure 4A comparison chart before and after the removal of chloride ions in a leachate provided in an embodiment of the invention. DETAILED DESCRIPTION

[0030] like Figure 1 As shown, this embodiment proposes a leachate biochemical treatment process, comprising the following steps:

[0031] S01: After adjusting the pH value of the leachate to 7-9, the leachate is then introduced into a biochemical reaction tank, and aerobic bacteria are added to the reaction tank to perform microbial metabolism on the leachate;

[0032] S02: The leachate in the biochemical reaction tank is introduced into the aeration tank and allowed to stand for a period of time, the pH value is adjusted to 7.3-8.0, and the dissolved oxygen concentration after aeration is 2-8 mg / L;

[0033] S03: introducing the aerated leachate into a sedimentation tank for static treatment to remove suspended matter in the leachate;

[0034] S04: The leachate in the sedimentation tank is introduced into the deep treatment tank, and activated carbon, PAM solution, and PAC solution are added for stirring treatment, and the mixture is allowed to stand for a period of time to finally obtain effluent.

[0035] In the present application, by introducing the leachate into a biochemical reaction tank and adding aerobic bacteria to the reaction tank, the soluble organic matter in the leachate can be absorbed into the bacteria through the cell wall and cell membrane of the aerobic bacteria; at the same time, the colloids and suspended organic matter in the leachate are adsorbed on the surface of the aerobic bacteria, decomposed into soluble substances by the exoenzymes of the aerobic bacteria, and then enter the bacteria. In the bacteria, these organic substances are oxidized and degraded through the decomposition and metabolism process, and the energy released meets the needs of bacterial life activities; some of the oxidation intermediates form new cell substances through anabolism, promote the growth and reproduction of bacteria, and the final treatment product is a stable inorganic substance, which realizes the harmless treatment of leachate; by introducing the leachate into the aeration tank, the sludge in the leachate can be settled; by introducing the leachate in the aeration tank into the sedimentation tank, the suspended matter in the water is effectively removed by standing in the sedimentation tank, the water flow rate is reduced, and the water quality is purified; by adding activated carbon, PAM solution, and PAC solution in the deep treatment tank for stirring treatment, the organic matter, odor, pigment and other impurities in the water are effectively removed by the added activated carbon powder; by adding PAM solution and PAC solution, the suspended particles in the leachate are aggregated into larger floccules, the sedimentation is accelerated, the solid-liquid separation efficiency is improved, and the effect of purifying water quality is further achieved. Through the coordinated cooperation of each step in the present application, the content of ammonia nitrogen, chemical oxygen demand, etc. in the leachate is effectively reduced, the efficiency and stability of leachate treatment are improved, and the disposal cost is reduced.

[0036] Preferably, the dissolved oxygen concentration in the reaction tank is 2-5 mg / L. Specifically, the dissolved oxygen concentration is 2 mg / L, 3 mg / L, 3.5 mg / L, 4 mg / L, 4.5 mg / L, 5 mg / L, etc. Of course, in the present application, the dissolved oxygen concentration in the reaction tank is adaptively adjusted according to the volume of the leachate to meet the oxygen demand of aerobic bacteria in the leachate.

[0037] Preferably, the aerobic bacteria may be any one of nitrifying bacteria, denitrifying bacteria, Bacillus, Pseudomonas, Steinernea, and Pseudomonas aeruginosa. Specifically, in this embodiment, the aerobic bacteria are nitrifying bacteria, and the ammonia nitrogen in the leachate is converted into nitrate by the nitrifying bacteria, thereby effectively removing the ammonia nitrogen in the leachate, reducing harmful substances in the water, and improving the water quality.

[0038] Furthermore, step S01 also includes:

[0039] The leachate is introduced into the regulating pond and mixed with rainwater to adjust the pH value of the leachate to 7-9; and the chemical oxygen demand in the leachate is 200-500 mg / L, the ammonia nitrogen content is 40-90 mg / L, and the chloride ion content is 8000-20000 mg / L.

[0040] In the present application, the leachate is introduced into the regulating tank in advance and mixed with rainwater to dilute the leachate so that the pH value of the leachate meets the survival requirements of aerobic bacteria in the subsequent biochemical reaction tank. At the same time, through dilution treatment, the chemical oxygen demand, ammonia nitrogen content, and chloride ion content in the leachate can meet the purification requirements of the subsequent treatment process, so that the leachate treated by this process can meet the emission limit requirements of GB18598-2019 "Hazardous Waste Landfill Pollution Control Standards".

[0041] Specifically, in the present application, after being mixed and adjusted with rainwater, the chemical oxygen demand in the leachate can be 200mg / L, 250mg / L, 300mg / L, 350mg / L, 400mg / L, 450mg / L, and 500mg / L, etc.; the ammonia nitrogen content in the leachate can be 40mg / L, 50mg / L, 60mg / L, 70mg / L, 80mg / L, 90mg / L, etc.; the chloride ion content in the leachate is 8000mg / L, 9000mg / L, 10000mg / L, 12000mg / L, 14000mg / L, 16000mg / L, 20000mg / L, etc. Of course, in the present implementation, it can be controlled according to the actual volume of the leachate, and it is not the only limitation here.

[0042] Further, the step S02 includes:

[0043] A: Introduce the leachate from the biochemical reaction tank into the first aeration tank, adjust the pH value to 7.3-8.0, and the dissolved oxygen to 2-4 mg / L;

[0044] B: When the sludge volume content in the first aeration tank is 15%-25%, the leachate is introduced into the second aeration tank and the pH value is adjusted to 7.3-8.0 and the dissolved oxygen is 4-6 mg / L;

[0045] C: When the sludge concentration in the second aeration tank is 15%-25%, the leachate is introduced into the third aeration tank and the pH value is adjusted to 7.3-8.0 and the dissolved oxygen is 4-7 mg / L;

[0046] D: When the sludge concentration in the third aeration tank is 9%-15%, the leachate is introduced into the sedimentation tank for static treatment.

[0047] In the present application, the leachate in the biochemical reaction tank is introduced into the first aeration tank for static treatment, and the pH value and dissolved oxygen content in the leachate are controlled to achieve sludge sedimentation in the leachate. When the sludge volume content in the leachate is 15%-25%, the leachate is introduced into the second aeration tank, and the concentration of dissolved oxygen is controlled so that the leachate is statically treated in the second aeration tank, and the sludge sedimentation in the leachate is further achieved; when the sludge concentration in the leachate is 15%-25%, the leachate is introduced into the third aeration tank, and the sludge sedimentation in the leachate is further achieved through the third aeration tank, and the sludge in the leachate is further sedimented. By controlling different dissolved oxygen contents, the leachate is statically treated three times in the aeration tank, thereby effectively reducing the sludge content in the leachate and further improving the water quality in the leachate.

[0048] Preferably, the standing time in the aeration tank is 8-9 hours. Of course, in the present application, the standing time of the leachate in each aeration tank is adjusted in real time according to the sludge settling result in the leachate, which is not the only limitation here.

[0049] Preferably, when the sludge volume content in the first aeration tank is SV3015%-25%, the leachate in the first aeration tank can be introduced into the second aeration tank. In the present application, SV30 represents the sludge settling volume, which means the volume ratio of the precipitated sludge to the mixed liquid after the mixed aeration tank activated sludge mixed liquid is quickly poured into a 1000ml measuring cylinder to the full scale and allowed to settle for 30 minutes.

[0050] Preferably, the settling time in the sedimentation tank is 9-12 hours. The settling time allows the suspended particles in the leachate to aggregate into larger flocs and have sufficient time to settle, thereby purifying the water quality.

[0051] Preferably, in the present application, step S04 includes:

[0052] The leachate in the sedimentation tank is introduced into the deep treatment tank, the frequency of the activated carbon feeder is controlled to 5-50HZ, and activated carbon is added to the leachate. When the chemical oxygen content in the leachate is ≤35mg / L, the activated carbon feeder stops feeding.

[0053] Specifically, in the present application, when the chemical oxygen content in the leachate is ≥75mg / L, the frequency of the activated carbon feeder can be 50HZ; when the chemical oxygen content in the leachate is 65-75mg / L, the frequency of the activated carbon feeder can be controlled to 30HZ; when the chemical oxygen content in the leachate is 55-65mg / L, the frequency of the activated carbon feeder can be controlled to 20HZ; when the chemical oxygen content in the leachate is 45-55mg / L, the frequency of the activated carbon feeder can be controlled to 10HZ; when the chemical oxygen content in the leachate is 35-45mg / L, the frequency of the activated carbon feeder can be controlled to 5HZ; when the chemical oxygen content in the leachate is ≤35mg / L, the activated carbon feeder stops feeding. By adjusting the frequency of the activated carbon feeder according to the different chemical oxygen content in the leachate, the activated carbon can be effectively removed from the chemical oxygen content in the leachate, so that the amount of activated carbon can be accurately controlled, avoiding excessive waste and reducing disposal costs.

[0054] Preferably, the mass concentration of the PAC is 0.1-0.45 Kg / m 3 Specifically, the mass concentration of the PAM is 0.1%, 0.20%, 0.30%, 0.35%, 0.40%, etc. Of course, the specific mass concentration of the PAM can also be determined according to the actual volume of the leachate to be treated, which is not limited here.

[0055] Preferably, the mass concentration of the PAM is 0.003-0.3 Kg / m 3 Specifically, the mass concentration of the PAM is 0.003%, 0.05%, 0.01%, 0.105%, 0.2%, etc. Of course, the specific mass concentration of the PAM can also be determined according to the actual volume of the leachate to be treated, which is not limited here.

[0056] In this application, see Figures 2 to 4 As shown, through the coordinated cooperation of various steps, the contents of ammonia nitrogen, chemical oxygen demand, chloride ions, etc. in the influent leachate are effectively reduced, so that the leachate treated by this process can meet the emission limit requirements of GB18598-2019 "Hazardous Waste Landfill Pollution Control Standards", improve the efficiency and stability of leachate treatment, and reduce disposal costs.

[0057] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A biochemical treatment process for leachate, characterized in that: The steps include: S01: After adjusting the pH value of the leachate to 7-9, the leachate is then introduced into a biochemical reaction tank, and aerobic bacteria are added to the reaction tank to perform microbial metabolism on the leachate; S02: The leachate in the biochemical reaction tank is introduced into the aeration tank and allowed to stand for a period of time, the pH value is adjusted to 7.3-8.0, and the dissolved oxygen concentration after aeration is 2-8 mg / L; S03: introducing the aerated leachate into a sedimentation tank for static treatment to remove suspended matter in the leachate; S04: The leachate in the sedimentation tank is introduced into the deep treatment tank, and activated carbon, PAM solution, and PAC solution are added for stirring treatment, and the mixture is allowed to stand for a period of time to finally obtain effluent.

2. A leachate biochemical treatment process according to claim 1, characterized in that: The dissolved oxygen concentration in the reaction tank is 2-5 mg / L.

3. A biochemical treatment process for leachate according to claim 1, characterized in that: The aerobic bacteria is any one of nitrifying bacteria, denitrifying bacteria, Bacillus, Pseudomonas, Steinernea, and Aerobacterium fluorescens.

4. A biochemical treatment process for leachate according to claim 1, characterized in that: The step S01 further includes: The leachate is introduced into the regulating pond and mixed with rainwater to adjust the pH value of the leachate to 7-9; and the chemical oxygen demand in the leachate is 200-500 mg / L, the ammonia nitrogen content is 40-90 mg / L, and the chloride ion content is 8000-20000 mg / L.

5. A biochemical treatment process for leachate according to claim 1, characterized in that: The step SO2 comprises: A: Introduce the leachate from the biochemical reaction tank into the first aeration tank, adjust the pH value to 7.3-8.0, and the dissolved oxygen to 2-4 mg / L; B: When the sludge volume content in the first aeration tank is 15%-25%, the leachate is introduced into the second aeration tank and the pH value is adjusted to 7.3-8.0 and the dissolved oxygen is 4-6 mg / L; C: When the sludge concentration in the second aeration tank is 15%-25%, the leachate is introduced into the third aeration tank and the pH value is adjusted to 7.3-8.0 and the dissolved oxygen is 4-7 mg / L; D: When the sludge concentration in the third aeration tank is 9%-15%, the leachate is introduced into the sedimentation tank for static treatment.

6. A biochemical treatment process for leachate according to claim 5, characterized in that: The standing time in the sedimentation tank is 9-12 hours.

7. The biochemical treatment process for leachate according to claim 1, characterized in that: The step S04 comprises: The leachate in the sedimentation tank is introduced into the deep treatment tank, the frequency of the activated carbon feeder is controlled to 5-50HZ, and activated carbon is added to the leachate. When the chemical oxygen content in the leachate is ≤35mg / L, the activated carbon feeder stops feeding.

8. The biochemical treatment process for leachate according to claim 1, characterized in that: The mass concentration of the PAC is 0.1-0.45 Kg / m 3 .

9. A biochemical treatment process for leachate according to claim 1, characterized in that: The mass concentration of the PAM is 0.003-0.02 Kg / m 3 .

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