CN-117658325-B - Anaerobic-AOAO (anaerobic-AOAO) multi-cycle treatment system and method for fresh landfill leachate

CN117658325BCN 117658325 BCN117658325 BCN 117658325BCN-117658325-B

Abstract

The invention discloses a fresh garbage leachate anaerobic-AOAO multi-circulation treatment system, which comprises an adjusting tank, a primary sedimentation tank, a middle tank, an anaerobic reactor, a circulation tank, a middle sedimentation tank, a primary anoxic tank, a primary aerobic tank, a secondary anoxic tank, a secondary aerobic tank and a secondary sedimentation tank which are sequentially communicated, wherein the middle tank is respectively communicated with the anaerobic reactor and the primary anoxic tank through a liquid inlet pipe and an overrun pipe, the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank and the secondary anoxic tank are connected end to end, the tail section of the primary aerobic tank is connected to the primary anoxic tank through a pipeline, the bottom of the secondary sedimentation tank is respectively connected with the middle sedimentation tank and the primary anoxic tank through a pipeline, and the water outlet of the secondary sedimentation tank is communicated with the adjusting tank. The invention also discloses a fresh landfill leachate anaerobic-AOAO multicycle treatment method, which solves the problem that the existing method is difficult to remove soluble microorganism products, reduces the inhibition of ammonia nitrogen to the microorganism below the inhibition concentration, thereby improving the activity of sludge and the pollutant removal rate.

Inventors

HE CHAO
LIU YONGHONG
CUI WEI

Assignees

西安工程大学

Dates

Publication Date: 20260512
Application Date: 20231031

Claims (8)

1. The anaerobic-AOAO multi-cycle treatment method for the fresh landfill leachate is characterized by being implemented by a multi-cycle treatment system and specifically comprising the following steps of: Step 1, mixing the original percolate flow Q1 with the water outlet reflux quantity Q2 from a secondary sedimentation tank (11) in a regulating tank (1); step 2, pumping the mixed percolate into a primary sedimentation tank (2), removing most suspended matters through sedimentation, and then entering a middle tank (3); Step 3, pumping the percolate in the middle tank (3) into the anaerobic reactor (4) by a pump and directly into the primary anoxic tank (7) through an overrunning pipe, wherein the flow rate of the pumped anaerobic reactor (4) is Q3, and the flow rate of the pumped primary anoxic tank (7) is Q4; step 4, the effluent of the anaerobic reactor (4) enters an outer circulation tank (5), a part of the effluent returns to the anaerobic reactor (4) from the bottom of the outer circulation tank (5), and the flow rate of the part is Q5; Step 5, mixing overflow water at the upper part of the external circulation tank (5) and part of residual sludge R2 from the secondary sedimentation tank (11) in a pipeline, and then entering an intermediate sedimentation tank (6); Step 6, the effluent of the intermediate sedimentation tank (6) enters a primary anoxic tank (7) and sequentially passes through the primary anoxic tank (7), a primary aerobic tank (8), a secondary anoxic tank (9) and a secondary aerobic tank (10) which are connected end to end; At the end of the first-stage aerobic tank (8), refluxing a nitrate nitrogen-containing mud-water mixture, namely nitrifying liquid, to the first-stage anoxic tank (7), wherein the nitrifying liquid reflux quantity is Q6; Step 7, mud-water separation is realized in a secondary sedimentation tank (11) by a mud-water mixture subjected to two-stage anoxic and two-stage aerobic treatment, a part of residual sludge R2 of sediment sludge at the lower layer of the secondary sedimentation tank (11) flows back to an intermediate sedimentation tank (6), is mixed with incoming water and is precipitated and discharged as residual sludge, the other part of sludge R1 of the secondary sedimentation tank flows back to a primary anoxic tank (7) to maintain the sludge concentration required by an AOAO system method, the backflow sludge R1 of the secondary sedimentation tank and the flow rate Q < 3 > +Q < 4 > entering the primary anoxic tank are called as sludge backflow ratio, the sludge backflow ratio is 1, a part of supernatant fluid of the secondary sedimentation tank (11) returns to an adjusting tank according to the water backflow ratio Q < 2 >/Q < 1 > to be mixed with original leachate to dilute the original leachate, and the overflow of the rest supernatant fluid of the secondary sedimentation tank (11) is treated effluent of the system, and the water flow rate is Q7; The multi-circulation treatment system comprises an adjusting tank (1), a primary sedimentation tank (2), a middle tank (3), an anaerobic reactor (4), an outer circulation tank (5), a middle sedimentation tank (6), a primary anoxic tank (7), a primary aerobic tank (8), a secondary anoxic tank (9), a secondary aerobic tank (10) and a secondary sedimentation tank (11), wherein the middle tank (3) is respectively communicated with the anaerobic reactor (4) and the primary anoxic tank (7) through a liquid inlet pipe and an overrun pipe, the primary anoxic tank (7), the primary anoxic tank (8), the secondary anoxic tank (9) and the secondary anoxic tank (10) are connected end to end, the tail section of the primary anoxic tank (8) is connected to the primary anoxic tank (7) through a pipeline, the bottom of the secondary sedimentation tank (11) is respectively connected with the middle sedimentation tank (6) and the primary anoxic tank (7) through a pipeline, and the water outlet of the secondary sedimentation tank (11) is communicated with the adjusting tank (1); The primary anoxic tank (7) and the secondary anoxic tank (9) are internally provided with stirrers, the primary aerobic tank (8) and the secondary anoxic tank (10) are internally provided with aeration devices, and the volume of the primary anoxic tank (7) is equal to the volume of the primary anoxic tank (8), the volume of the secondary anoxic tank (9) is equal to the volume of the secondary anoxic tank (10) =30:50-53:8-12:8-10.
2. The anaerobic-AOAO multi-cycle treatment method for fresh landfill leachate according to claim 1, wherein the flow ratio of the effluent reflux to the original leachate in the step 1 is called an effluent reflux ratio, namely Q2/Q1, and the effluent reflux ratio is 5-7.
3. The anaerobic-AOAO multicycle treatment method of fresh landfill leachate according to claim 1, wherein the ratio of the flow Q3 pumped into the anaerobic reactor (4) and the flow Q4 directly entering the primary anoxic tank (7) through the overrun pipe is q3:q4=7-8:2-3.
4. The anaerobic-AOAO multi-cycle treatment method for fresh landfill leachate according to claim 1, wherein a part of effluent of the external circulation tank (5) in the step 4 enters the reactor from the bottom of the anaerobic reactor (4) through a circulation pump, the up-flow speed of the reactor is increased, the part of effluent is Q5, and the part of effluent is used for maintaining the expansion state of the sludge bed of the anaerobic reactor (4), and the size of the effluent depends on the type of the anaerobic reactor and can be calculated according to a formula (1): wherein U is the upward flow rate of a liquid hollow tower in the reactor, the unit is m/h, A is the horizontal sectional area of the anaerobic reactor, the unit is m 2 , and the unit of Q3 and Q5 is m 3 /h.
5. The anaerobic-AOAO multi-cycle treatment method for fresh landfill leachate according to claim 1, wherein the primary anoxic tank (7) and the secondary anoxic tank (9) in the step 6 achieve the purpose of removing nitrogen by converting nitrate nitrogen into nitrogen gas, and simultaneously reduce a part of organic carbon.
6. The anaerobic-AOAO multicycle treatment method of fresh landfill leachate according to claim 1, wherein the primary aerobic tank (8) and the secondary aerobic tank (10) in the step 6 are used for converting ammonia nitrogen into nitrate nitrogen while removing a large amount of organic matters.
7. The anaerobic-AOAO multi-cycle treatment method for fresh landfill leachate according to claim 1, wherein the ratio Q6/(q3+q4) of the nitrifying liquid reflux quantity Q6 and the water quantity q3+q4 entering the anoxic tank in the step 6 is called nitrifying liquid reflux ratio, and the nitrifying liquid reflux ratio is 3-4.
8. The anaerobic-AOAO multicycle treatment method of fresh garbage leachate according to any one of claims 1-7, wherein a stirrer is arranged in the primary anoxic tank (7) and the secondary anoxic tank (9) to maintain the suspension state of microbial sludge and the good mixing of sludge and wastewater, an aeration device is arranged in the primary aerobic tank (8) and the secondary aerobic tank (10) to charge air into the sludge-water mixture to maintain a certain dissolved oxygen concentration and the suspension state of sludge, and the effective volume of each tank is that the primary anoxic tank (7) is 30%, the primary aerobic tank (8) is 50-53%, the secondary anoxic tank (9) is 8.0-12%, and the secondary aerobic tank (10) is 8.0-10%.

Description

Anaerobic-AOAO (anaerobic-AOAO) multi-cycle treatment system and method for fresh landfill leachate Technical Field The invention belongs to the technical field of organic wastewater treatment methods, and particularly relates to a fresh landfill leachate anaerobic-AOAO multi-cycle treatment system and a fresh landfill leachate anaerobic-AOAO multi-cycle treatment method. Background Further removal of residual organics (EfOM) in the organic wastewater biological treatment effluent is key to improving the organic wastewater treatment efficiency, and studies have shown that EfOM is mainly composed of Soluble Microbial Products (SMP) produced during the treatment process, which cannot be effectively degraded in the conventional treatment method. Because of the ultrahigh concentration of the fresh percolate and the positive correlation between the generated amount of SMP and the concentration of the raw wastewater, the concentration of the SMP in the fresh percolate is high, and the quality of the effluent is seriously influenced. Some studies have considered that traditional wastewater treatment methods have difficulty removing SMP and that additional treatment should be performed to further subtract them. Meanwhile, the fresh leachate has high ammonia nitrogen concentration, and the high-efficiency denitrification and COD removal must be completed at the same time when the fresh leachate reaches the standard. At present, the main flow method for treating fresh percolate adopts the technology of landfill percolate, and mostly adopts the technology of coagulation and treatment-anaerobic-aerobic anoxic biological treatment, as well as the technology of advanced oxidation, microfiltration and nanofiltration and reverse osmosis, while the concentrated solution which is produced after Nanofiltration (NF) and (RO) and accounts for about 35-45% of the original wastewater amount because of high-concentration salinity and refractory organic matters cannot be returned to the system for treatment, and the economically reasonable treatment and disposal technology cannot be found. The term "fresh leachate (FRESH LEACHATE)" refers to leachate from municipal refuse incineration plants and municipal domestic waste transfer sites, which are distinguished from leachate from landfill sites in nature. Disclosure of Invention The first object of the invention is to provide an anaerobic-AOAO multicycle biological treatment system of fresh landfill leachate, which solves the problem that microorganism products are difficult to remove by the existing wastewater treatment method. The second purpose of the invention is to provide an anaerobic-AOAO multicycle biological treatment method of fresh landfill leachate, which can overcome the excessive dependence of the traditional technology on the membrane method by greatly reducing the concentration of organic matters in effluent, thereby laying a foundation for reducing the cost and overcoming the thick liquid problem of membrane interception. The first technical scheme adopted by the invention is that the fresh garbage leachate anaerobic-AOAO multi-cycle treatment system comprises an adjusting tank, a primary sedimentation tank, a middle tank, an anaerobic reactor, an outer circulation tank, a middle sedimentation tank, a primary anoxic tank, a primary aerobic tank, a secondary anoxic tank, a secondary aerobic tank and a secondary sedimentation tank which are sequentially communicated, wherein the middle tank is respectively communicated with the anaerobic reactor and the primary anoxic tank through a liquid inlet pipe and an overrun pipe, the primary anoxic tank, the primary aerobic tank, the secondary anoxic tank and the secondary anoxic tank are connected end to end, the tail section of the primary anoxic tank is connected to the primary anoxic tank through a pipeline, the bottom of the secondary sedimentation tank is respectively connected with the middle sedimentation tank and the primary anoxic tank through a pipeline, and the water outlet of the secondary sedimentation tank is communicated with the adjusting tank. The first technical scheme adopted by the invention is characterized in that: the primary anoxic tank and the secondary anoxic tank are internally provided with stirrers, the primary anoxic tank and the secondary anoxic tank are internally provided with aeration devices, the primary anoxic tank volume is equal to the primary anoxic tank volume, the secondary anoxic tank volume is equal to the secondary anoxic tank volume, and the secondary anoxic tank volume is equal to Chi Rongji =30:50-53:8-12:8-10. The second technical scheme adopted by the invention is that the anaerobic-AOAO multicycle treatment method of the fresh landfill leachate is implemented according to the following steps: Step 1, mixing original percolate flow Q1 with water outlet reflux quantity Q2 from a secondary sedimentation tank in an adjusting tank; step 2, pumping the mixed percolate into a primary