CN109721157B

CN109721157B - Device and method for treating late landfill leachate through shortcut nitrification/anaerobic ammonia oxidation/shortcut denitrification-anaerobic ammonia oxidation process

Info

Publication number: CN109721157B
Application number: CN201910051959.0A
Authority: CN
Inventors: 彭永臻; 张方斋; 王众; 姜浩
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2019-01-21
Filing date: 2019-01-21
Publication date: 2021-10-26
Anticipated expiration: 2039-01-21
Also published as: CN109721157A

Abstract

A device and method for treating late-stage landfill leachate by a short-path nitrification/anammox/short-path denitrification-anammox process belong to the field of biological treatment of high ammonia nitrogen sewage sludge. The late landfill leachate first enters the PN‑SBR, and the influent ammonia nitrogen is all oxidized to nitrite nitrogen; the effluent containing nitrite nitrogen enters the AMX‑SBR together with a part of the late landfill leachate for denitrification through anaerobic ammonia oxidation; The AMX‑SBR effluent of nitrate nitrogen is pumped into the DEAMOX‑UASB reactor together with another part of late landfill leachate and an external carbon source. effect to complete further deep removal; the present invention proposes a new biological denitrification process, which solves the problems of low denitrification efficiency and high TN of effluent in late stage landfill leachate, and reduces the consumption of external carbon sources; the process is flexible and easy to control, suitable for In-depth removal of high ammonia nitrogen wastewater.

Description

Device and method for treating late landfill leachate through shortcut nitrification/anaerobic ammonia oxidation/shortcut denitrification-anaerobic ammonia oxidation process

Technical Field

The invention relates to a device and a method for treating late landfill leachate by a shortcut nitrification/anaerobic ammonia oxidation/shortcut denitrification-anaerobic ammonia oxidation process, belonging to the field of biological treatment of high ammonia nitrogen sewage and sludge.

Background

In recent years, with the increasing production of municipal solid waste, landfill has become the most widely used treatment and disposal method in the world. The leachate generated by landfill has the water quality characteristics of complex components, large water quality and water quantity change, high concentration of organic matters and ammonia nitrogen, imbalance proportion of microorganism nutrient elements and the like, so that the treatment of the leachate becomes one of the unsolved problems in the international range. NH is treated by the traditional biological denitrification process₄ ⁺Conversion of-N to NO₃ ^-N, and NO by denitrification₃ ^-N is converted to nitrogen which escapes from the water. Denitrification stage with NO₃ ^-and-N is an electron acceptor, and the organic matter is used as an electron donor to convert ammonia nitrogen into nitrogen to complete biological denitrification. The serious shortage of organic carbon source is a barrier that the denitrification efficiency of the leachate at the late stage cannot be improved, so that the traditional biological denitrification efficiency is only improvedCan reach about 10 percent, and the added organic carbon source can greatly increase the cost of sewage denitrification.

The anaerobic ammonia oxidation technology belongs to an autotrophic nitrogen removal process, does not need an organic carbon source, has low sludge yield and does not need aeration, and is suitable for high ammonia nitrogen wastewater such as low C/N ratio late-stage landfill leachate and the like. But a great amount of nitrate nitrogen generated in the anaerobic ammonia oxidation process is the main reason for the substandard effluent. The problem of high nitrate nitrogen in the anaerobic ammonia oxidation effluent can be effectively solved in the short-cut denitrification process, the anaerobic ammonia oxidation and the short-cut denitrification can be simultaneously carried out in a single reactor, nitrate nitrogen generated by the anaerobic ammonia oxidation is reduced into nitrite nitrogen by short-cut denitrification bacteria, and the generated nitrite nitrogen is further removed by the anaerobic ammonia oxidation, so that the effluent TN concentration can be effectively reduced compared with that of the traditional anaerobic ammonia oxidation process.

The advanced landfill leachate with high ammonia nitrogen concentration realizes stable nitrite nitrogen accumulation in PN-SBR through a short-cut nitrification process, nitrite nitrogen in short-cut nitrification effluent and part of ammonia nitrogen in the advanced landfill leachate are removed in AMX-SBR through an anaerobic ammonia oxidation process, nitrate nitrogen generated in the anaerobic ammonia oxidation process is firstly reduced into nitrite nitrogen by short-cut denitrifying bacteria in DEAMOX-UASB, and the nitrite nitrogen is further removed through in-situ anaerobic ammonia oxidation.

Disclosure of Invention

The invention provides a device and a method for treating advanced landfill leachate by a shortcut nitrification/anaerobic ammonium oxidation/shortcut denitrification-anaerobic ammonium oxidation process, and particularly the advanced landfill leachate firstly enters PN-SBR, and all ammonia nitrogen in inflow water is oxidized into nitrite nitrogen; effluent containing nitrite nitrogen and a part of late landfill leachate enter AMX-SBR together for denitrification through anaerobic ammoxidation; the effluent of AMX-SBR containing nitrate nitrogen, the other part of late landfill leachate and an external carbon source are pumped into a DEAMOX-UASB reactor at the same time, the nitrate nitrogen is firstly reduced into nitrite nitrogen by short-range denitrifying bacteria, and then further deep removal is completed through anaerobic ammonia oxidation.

The purpose of the invention is realized by the following technical scheme:

the device for treating the late landfill leachate by the short-cut nitrification/anaerobic ammonia oxidation/short-cut denitrification-anaerobic ammonia oxidation process is characterized by comprising a raw water tank (1), a short-cut nitrification reactor (PN-SBR) (2), a first intermediate water tank (3), an anaerobic ammonia oxidation reactor (AMX-SBR) (4), a second intermediate water tank (5), an external carbon source storage tank (6.5) and a short-cut denitrification-anaerobic ammonia oxidation reactor (DEAMOX-UASB) (6);

the raw water tank is provided with a first water outlet (1.1) and a second water outlet (1.2); the PN-SBR is provided with an air compressor (2.1), a gas flow meter (2.2), an aeration sand head (2.9), a first water inlet (2.4), a first sampling port (2.7), a first water discharge port (2.8), a first stirrer (2.5), a first water inlet peristaltic pump (2.3), a pH/DO real-time monitoring device (2.6) and a first ORP real-time monitoring device (2.4); the AMX-SBR is provided with a second water inlet (4.2), a second sampling port (4.7), a second water outlet (4.8), a second water inlet peristaltic pump (4.3), a third water inlet peristaltic pump (4.1), a second stirrer (4.5), a pH real-time monitoring device (4.6) and a second ORP real-time monitoring device (4.4); the DEAMOX-UASB is provided with a vent pipe (6.8), a third water inlet (6.3), a fourth water inlet peristaltic pump (6.2), a fifth water inlet peristaltic pump (6.1), a first backflow port (6.10), a first backflow peristaltic pump (6.13), a second backflow port (6.12), a three-phase separator (6.14), an exhaust port (6.7), an air bag (6.6) and a third water outlet (6.9);

the raw water tank (1) is respectively connected with the PN-SBR (2), the AMX-SBR (4) and the DEAMOX-UASB (6) through a first water inlet peristaltic pump (2.3)/a third water inlet peristaltic pump (4.1)/a fifth water inlet peristaltic pump (6.1); a PN-SBR first water discharge port (2.8) is connected with a first intermediate water tank (3), and air is pumped into the PN-SBR (2) through an aeration sand head (2.9) finally through an air compressor (2.1) and a gas flow meter (2.2); the first intermediate water tank (3) is connected with a second water inlet (4.2) of the AMX-SBR through a second water inlet peristaltic pump (4.3); the AMX-SBR second water outlet (4.8) is connected with a water inlet (5.1) of the second intermediate water tank; a water outlet (5.2) of the second intermediate water tank is connected with a DEAMOX-UASB (6) through a fourth water inlet peristaltic pump (6.2); an external carbon source storage tank (6.5) is connected with DEAMOX-UASB (6); the DEAMOX-UASB first return port (6.10) is connected to the second return port (6.12) via a first peristaltic return pump (6.13).

Utilize the device to realize advanced denitrification of landfill leachate of late stage, its characterized in that, including the following process:

1) short-cut nitrification sludge, anaerobic ammonium oxidation sludge and short-cut denitrification anaerobic ammonium oxidation sludge are respectively added into PN-SBR, AMX-SBR and DEAMOX-UASB, and the sludge concentration of mixed liquor of each reactor after the addition is controlled to be 4035-4523mg/L, 4329-4638mg/L and 4362-5720mg/L respectively.

2) Pumping the late landfill leachate in the raw water tank into PN-SBR, opening a first stirrer and an air compressor, controlling the concentration of dissolved oxygen of the PN-SBR to be 0.2-0.5mg/L, consuming alkalinity in the short-cut nitrification process, when the pH value is reduced to the lowest value and the ammonia valley point after the reaction is finished, strictly controlling the aeration time through a pH/DO real-time monitoring device, stopping aeration when the ammonia valley point appears in a pH curve, closing the first stirrer and the air compressor, and discharging water after precipitating for 30 min.

3) And respectively opening a second water inlet peristaltic pump and a third water inlet peristaltic pump to simultaneously pump nitrite nitrogen-containing wastewater in the first intermediate water tank and late landfill leachate in the raw water tank into AMX-SBR. The anaerobic ammonia oxidation process is a process for generating alkalinity, pH continuously rises along with the reaction, after the anaerobic ammonia oxidation reaction is finished, an inflection point appears on a pH curve and stops increasing, the anoxic stirring time is strictly controlled by a pH real-time monitoring device, stirring is stopped when the inflection point appears on the pH curve, the second stirrer is closed, and after 30min of precipitation, supernate is discharged into a second middle water tank.

4) And respectively opening a fourth water inlet peristaltic pump and a fifth water inlet peristaltic pump to simultaneously pump nitrate nitrogen wastewater in the second intermediate water tank and late landfill leachate in the raw water tank into DEAMOX-UASB. And controlling the flow rates of the fourth and fifth water inlet peristaltic pumps to be 0.24L/h and 0.022L/h respectively, enabling DEAMOX-UASB wastewater to enter the second return port from the first return port through the first return peristaltic pump, and controlling the flow rate of the first return peristaltic pump to be 0.45L/h.

Principle of the technology

The device and the method for treating the late landfill leachate by the short-cut nitrification/anaerobic ammonia oxidation/short-cut denitrification-anaerobic ammonia oxidation process are characterized in that the late landfill leachate firstly enters PN-SBR, and all the inflow ammonia nitrogen is oxidized into nitrite nitrogen; effluent containing nitrite nitrogen and a part of late landfill leachate enter AMX-SBR together for denitrification through anaerobic ammoxidation; the effluent of AMX-SBR containing nitrate nitrogen, the other part of late landfill leachate and an external carbon source are pumped into a DEAMOX-UASB reactor at the same time, the nitrate nitrogen is firstly reduced into nitrite nitrogen by short-range denitrifying bacteria, and further deep removal is completed through anaerobic ammonia oxidation; the invention provides a novel biological denitrification process, which solves the problems of low denitrification efficiency and high TN of effluent of late landfill leachate and reduces the consumption of an external carbon source; the process is flexible and changeable, is easy to regulate and control, and is suitable for deep removal of high ammonia nitrogen wastewater.

The device and the method for treating the advanced landfill leachate by the shortcut nitrification/anaerobic ammonium oxidation/shortcut denitrification-anaerobic ammonium oxidation process have the following advantages that:

1) by organically combining short-cut nitrification, short-cut denitrification and anaerobic ammonia oxidation, the deep denitrification of the late-stage landfill leachate is really realized, and the purposes of saving carbon source addition and treatment cost are achieved;

2) the aeration time is controlled in real time through the pH curve to convert all the ammonia nitrogen in the inlet water into nitrite nitrogen, and the real-time control strategy can not only strictly control the nitrification in the short-cut nitrification stage, but also avoid NOB increase and energy waste caused by over-aeration;

3) the reaction time of the shortcut nitrification and the anaerobic ammonia oxidation is controlled in real time by adopting a pH curve, and when the water quality of the landfill leachate in the late stage of water inlet fluctuates, the system can still stably operate, so that the nitrogen in the system can be efficiently removed;

4) the process can reduce nitrate nitrogen generated by anaerobic ammonia oxidation and remove the nitrate nitrogen in situ, effectively improves the total nitrogen removal rate, and has high reaction rate of short-range denitrification and anaerobic ammonia oxidation and high nitrogen removal load;

5) the DEAMOX-UASB short-cut denitrification only reduces nitrate nitrogen to nitrite nitrogen, so that the consumption of carbon source is less, and the sludge yield is less than that of the traditional denitrification process, thereby reducing the energy consumption and cost of the subsequent sludge treatment.

Drawings

FIG. 1 is a schematic view of the apparatus of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

The water used for the specific test of the embodiment is the actual late-stage landfill leachate, the average ammonia nitrogen concentration is 1736 +/-40 mg/L, the COD average concentration is 2109 +/-200 mg/L, and the average alkalinity is 4000 +/-1000 mg/L (as CaCO)₃Meter). The PN-SBR test adopts sequencing batch SBR, the effective volume is 10L, and the water drainage ratio is 50%; the AMX-SBR adopts sequencing batch SBR with the effective volume of 10L and the water drainage ratio of 80 percent; the effective volume of the DEAMOX-UASB adopting an up-flow anaerobic sludge bed reactor (UASB) is 2L;

the specific operation process is as follows:

The continuous test results show that:

the process has total nitrogen removal rate and total nitrogen removal rate of 99.5% and 0.43kg/m under the conditions that the concentrations of ammonia nitrogen, total nitrogen and COD in the inlet water are 1736 +/-40 mg/L, 2023 +/-75 mg/L and 2109 +/-200 mg/L respectively³d. Water outlet TN<10mg/L, and reaches the landfill leachate discharge standard.

Claims

1. A method for realizing deep denitrification of late-stage landfill leachate by using a short-path nitrification/anammox/short-path denitrification-anammox device, the devices used include a raw water tank (1), a short-path nitrification reactor PN-SBR (2) , the first intermediate water tank (3), the anammox reactor AMX-SBR (4), the second intermediate water tank (5), the external carbon source storage tank (6.5), the short-range denitrification-anammox reactor DEAMOX -UASB(6);

The raw water tank is provided with a first water outlet (1.1) and a second water outlet (1.2); the PN-SBR is provided with an air compressor (2.1), a gas flow meter (2.2), and an aerated sand head (2.9) , the first water inlet (2.4), the first sampling port (2.7), the first water outlet (2.8), the first agitator (2.5), the first water inlet peristaltic pump (2.3), the pH/DO real-time monitoring device ( 2.6), the first ORP real-time monitoring device (2.10); the AMX-SBR is provided with a second water inlet (4.2), a second sampling port (4.7), a second water outlet (4.8), and a second water inlet peristaltic pump (4.3), the third water inlet peristaltic pump (4.1), the second stirrer (4.5), the pH real-time monitoring device (4.6), the second ORP real-time monitoring device (4.4); the DEAMOX-UASB is provided with a venting pipe (6.8), the third water inlet (6.3), the fourth water inlet peristaltic pump (6.2), the fifth water inlet peristaltic pump (6.1), the first return port (6.10), the first return peristaltic pump (6.13), the first Second return port (6.12), three-phase separator (6.14), exhaust port (6.7), air bag (6.6), third drain port (6.9);

The raw water tank (1) is connected to the PN-SBR (2) and AMX-SBR (4) through the first inlet peristaltic pump (2.3), the third inlet peristaltic pump (4.1), and the fifth inlet peristaltic pump (6.1), respectively. Connected to DEAMOX-UASB (6); PN-SBR first water outlet (2.8) is connected to the first intermediate water tank (3), the air passes through the air compressor (2.1), the gas flow meter (2.2) and finally passes through the aeration sand head (2.9) Drive into the PN-SBR (2); the first intermediate water tank (3) is connected to the AMX-SBR second water inlet (4.2) through the second water inlet peristaltic pump (4.3); the AMX-SBR second water outlet ( 4.8) is connected to the water inlet (5.1) of the second intermediate water tank; the water outlet (5.2) of the second intermediate water tank is connected to the DEAMOX-UASB (6) through the fourth water inlet peristaltic pump (6.2); the external carbon source storage tank (6.5) Connect with DEAMOX-UASB (6); DEAMOX-UASB first return port (6.10) is connected with second return port (6.12) through first return peristaltic pump (6.13);

It is characterised in that the method comprises the following steps:

1) Add short-path nitrification sludge, anammox sludge, and short-path denitrification anammox sludge to PN-SBR, AMX-SBR, DEAMOX-UASB respectively, and control the mixed liquid sewage of each reactor after adding. The mud concentration is 4035-4523mg/L, 4329-4638mg/L and 4362-5720mg/L respectively;

2) Pump the late-stage landfill leachate in the raw water tank into the PN-SBR, turn on the first agitator and the air compressor, and control the dissolved oxygen concentration of the PN-SBR to be 0.2-0.5 mg/L. The alkalinity needs to be consumed during the short-range nitrification process. , when the pH drops to the lowest point after the reaction, that is, the "ammonia point", the aeration time is strictly controlled by the pH/DO real-time monitoring device. When the pH curve appears "ammonia point", the aeration is stopped, and the first agitator and air are closed. Compressor, drain after 30min of sedimentation;

3) Turn on the second water inlet peristaltic pump and the third water inlet peristaltic pump respectively to pump the waste water containing nitrous nitrogen in the first intermediate water tank and the late-stage landfill leachate in the raw water tank into the AMX-SBR at the same time; the anammox process is a In the process of generating alkalinity, as the reaction progresses, the pH continues to rise. When the anammox reaction ends, the pH curve will show an inflection point and stop growing. The anoxic stirring time is strictly controlled by the pH real-time monitoring device, and stops when the pH curve shows an inflection point. Stir, close the second stirrer, and discharge the supernatant into the second intermediate water tank after 30min of precipitation;

4) Turn on the fourth water inlet peristaltic pump and the fifth water inlet peristaltic pump respectively to pump the second intermediate water tank containing nitrate nitrogen waste water and raw water tank middle and late landfill leachate simultaneously into DEAMOX-UASB; control the fourth water inlet peristaltic pump and The flow rates of the fifth inlet peristaltic pump are 0.24L/h and 0.022L/h respectively. The DEAMOX-UASB waste water enters the second return port through the first return peristaltic pump through the first return port, and the flow rate of the first return peristaltic pump is controlled to be 0.45L /h.