CN114291962A - Device and method for treating late landfill leachate by three-stage plug-flow PN-PNA-DE process - Google Patents

Abstract

The device and method for treating late-stage landfill leachate by three-stage plug-flow PN-PNA-DE process belong to the field of biological treatment of high ammonia nitrogen wastewater. The leachate raw water and the effluent from the tertiary biochemical treatment are mixed in the primary regulating tank and then enter the PN biochemical tank, where the hydrolysis and denitrification of organic matter are carried out in the anoxic zone, the short-range nitrification reaction is carried out in the aerobic zone, and the in-situ FA in the anoxic zone is carried out. Treatment and in-situ FNA treatment in the aerobic zone are the keys to maintaining stable short-range nitrification and hydrolysis and acidification of organic matter in the PN biochemical pool. The initiation of the effluent reflux from the tertiary biochemical treatment relieved the inhibition of FA and FNA on AOB and denitrifying bacteria in the PN biochemical pool. The effluent from the primary biochemical treatment enters the PNA biochemical tank for autotrophic denitrification. The staged influent strategy alleviates the inhibition of FA on AnAOB and improves the utilization efficiency of the influent organic matter. The classification of the PN biochemical tank and the PNA biochemical tank is set to anaerobic ammonia. The oxidation process provides sufficient nitrous nitrogen. The invention realizes low-carbon, high-efficiency and deep denitrification.

Description

Device and method for treating late-stage landfill leachate by three-stage plug-flow PN-PNA-DE process

technical field

The invention is a three-stage plug-flow short-range nitrification/denitrification-short-range nitrification coupled anaerobic ammonium oxidation-deep denitrification technology as the core, and aims at how to achieve stable short-range nitrification while alleviating in-situ free ammonia and free nitrogen The invention relates to the inhibition of key functional bacteria by nitric acid treatment, so as to carry out high-efficiency and low-cost deep denitrification of late-stage landfill leachate, and belongs to the technical field of biological treatment of high-ammonia nitrogen wastewater.

Background technique

From 2004 to 2020, the annual removal volume of urban domestic waste in China increased from 1.55×10 ⁴ to 2.35×10 ^40,000 tons, and the harmless treatment rate increased from 52.1% to 99.7%. Landfilling is gradually being converted to incineration, but both produce landfill leachate. Among them, biological treatment is the most economical and low-carbon method for denitrification of landfill leachate.

Compared with the traditional nitrification-denitrification biological denitrification process, the short-range nitrification coupled anaerobic ammonium oxidation (PNA) process can theoretically save about 60% of aeration energy consumption and 100% of carbon source dosage, and is becoming more and more important. Widely used in landfill leachate biological treatment research. However, this technology for late-stage landfill leachate denitrification still faces the following problems: how to obtain a stable short-range nitrification effect; how to ensure a sufficient source of nitrite in the anammox process; use in-situ free ammonia (FA) and free nitrite Nitric acid (FNA) treatment inhibits nitrite oxidizing bacteria (NOB), how to alleviate the inhibition of ammonia oxidizing bacteria (AOB) and anaerobic ammonia oxidizing bacteria (AnAOB); how to achieve effective retention of AnAOB in the system; and how to The nitrates produced by the PNA process are further removed, etc.

SUMMARY OF THE INVENTION

The invention proposes a device and a method for treating late landfill leachate by a three-stage plug-flow PN-PNA-DE process. The leachate raw water first enters the PN biochemical tank. Under the anoxic in-situ FA treatment and aerobic in-situ FNA treatment, NOB is inhibited and elutriated, and organic matter hydrolysis and denitrification are carried out in the anoxic zone of the PN biochemical tank; primary biochemical treatment After the effluent and leachate raw water are mixed, they are divided into three stages and continuously enter the PNA biochemical tank, where anammox and denitrification are carried out in the anoxic zone, and the synchronous short-range nitrification coupled with anammox reaction is carried out in the aerobic zone; two The effluent from the first-stage biochemical treatment enters the DE biochemical tank for deep denitrification; after the effluent from the third-stage biochemical treatment is stabilized, the parameters of the system are optimized, and the effluent reflux device is activated to mix the effluent from the third-stage biochemical treatment with the raw leachate water and then pump it into the PN biochemical tank, thereby Improve ammonia nitrogen removal efficiency.

The device for treating late-stage landfill leachate by the three-stage plug-flow PN-PNA-DE process is characterized by comprising the following contents: a first-level regulating tank (1); a PN biochemical tank (2); a first-level sedimentation tank (3); two Level conditioning tank (4); PNA biochemical tank (5); Secondary sedimentation tank (6); Tertiary conditioning tank (7); DE biochemical tank (8); Tertiary sedimentation tank (9);

Among them, the PN biochemical tank inlet pump (2.10) continuously pumps the 1:1 mixture (1.2) of the leachate raw water and the tertiary biochemical treatment effluent from the first-level adjustment tank (1) through the PN biochemical tank inlet pipeline (2.11). PN biochemical tank compartment one (2.1) is mixed with activated sludge, and flows out from the PN biochemical tank compartment nine (2.9), into the PN biochemical tank outlet pipeline (2.19) and the first-level sedimentation tank (3); after precipitation, The supernatant liquid enters the secondary regulation tank (4) through the primary biochemical treatment effluent pump (4.3) and the primary biochemical treatment effluent pipeline (3.1), and the sludge in the primary sedimentation tank (3) returns through the primary sludge The pump (3.2) and the primary sludge return pipeline (3.3) are returned to the PN biochemical tank compartment 1 (2.1); the raw leachate water passes through the secondary conditioning tank inlet pump (4.1) and the secondary conditioning tank inlet pipeline (4.2). ) is pumped into the secondary regulating tank (4) and mixed with the effluent of the primary biochemical treatment; the mixed liquid in the secondary regulating tank (4) is passed through the PNA biochemical tank inlet pump one (5.10) and the PNA biochemical tank inlet pipeline one (5.11), PNA biochemical tank inlet pump two (5.12) and PNA biochemical tank inlet pipeline two (5.13), PNA biochemical tank inlet pump three (5.14) and PNA biochemical tank inlet pipeline three (5.15), respectively enter the PNA biochemical tank (5) PNA biochemical tank compartment one (5.1), PNA biochemical tank compartment four (5.4) and PNA biochemical tank compartment seven (5.7); ) into the secondary sedimentation tank (6); after precipitation, the supernatant in the secondary sedimentation tank (6) enters the tertiary adjustment tank (7) through the secondary biochemical treatment effluent pipeline (6.1); the secondary sedimentation tank (6) ) The bottom sludge is returned to the PNA biochemical tank compartment 1 (5.1) through the secondary sludge return pump (6.2) and the secondary sludge return pipeline (6.3); the sodium acetate solution is fed by the external carbon source pump (7.1) and the external carbon source feeding pipeline (7.2) enters the tertiary adjustment tank (7) and is mixed with the effluent of the secondary biochemical treatment; the mixed liquid in the tertiary adjustment tank (7) passes through the DE biochemical tank inlet pump (8.1) and the DE biochemical tank The water inlet pipeline (8.2) enters the front end of the anoxic zone (8.8) of the DE biochemical tank, and flows out from the end of the aerobic zone (8.9) of the DE biochemical tank, and enters the tertiary sedimentation tank (9) through the water outlet pipeline (8.10) of the DE biochemical tank. ; After precipitation, 50% of the supernatant enters the tertiary biochemical treatment effluent pipeline (9.1), and 50% of the supernatant enters the first-level adjustment tank (1) through the effluent return pump (9.5) and the effluent return pipeline (9.6); The sludge in the tertiary sedimentation tank (9) is returned to the anoxic zone (8.8) of the DE biochemical tank through the tertiary sludge return pump (9.3) and the tertiary sludge return pipeline (9.4);

In addition, the first-level adjustment tank (1) further includes a leachate raw water pipeline (1.1); the PN biochemical tank (2) further includes a PN biochemical tank compartment two (2.2), a PN biochemical tank compartment three (2.3) ), PN biochemical pool compartment four (2.4), PN biochemical pool compartment five (2.5), PN biochemical pool compartment six (2.6), PN biochemical pool compartment seven (2.7), PN biochemical pool compartment eight (2.8 ), PN biochemical pool temperature control device (2.12), PN biochemical pool heating device (2.13), PN biochemical pool pH and DO real-time monitoring device (2.14), PN biochemical pool mechanical stirrer (2.15), PN biochemical pool aeration device (2.16), PN biochemical tank gas flow meter (2.17), PN biochemical tank microporous aeration disc (2.18); the first-stage sedimentation tank also includes a first-stage biochemical treatment excess sludge discharge pipeline (3.4); the The PNA biochemical pool (5) also includes the PNA biochemical pool compartment two (5.2), the PNA biochemical pool compartment three, (5.3) the PNA biochemical pool compartment four (5.4), the PNA biochemical pool compartment five (5.5), the PNA biochemical pool compartment five (5.5), and the PNA biochemical pool compartment five (5.5). Cell six (5.6), PNA biochemical cell seven (5.7), PNA biochemical cell eight (5.8), PNA biochemical cell nine (5.9), PNA biochemical cell temperature control device (5.16), PNA biochemical cell Pool heating device (5.17), PNA biochemical pool pH and DO real-time monitoring device (5.18), PNA biochemical pool mechanical stirrer (5.19), PNA biochemical pool aeration device (5.20), PNA biochemical pool gas flow meter (5.21), PNA biochemical tank microporous aeration plate (5.22), biofilm carrier (5.23), biofilm carrier fixing frame (5.24); the DE biochemical tank (8) also includes a DE biochemical tank pH and DO real-time monitoring device (8.3) , DE biochemical pool mechanical stirrer (8.4), DE biochemical pool aeration device (8.5), DE biochemical pool gas flow meter (8.6), DE biochemical pool microporous aeration disc (8.7); the three-stage sedimentation tank ( 9) Also includes a tertiary biochemical treatment excess sludge discharge pipeline (9.2). The specific location is shown in Figure 1.

The method for late-stage landfill leachate treatment using the above-mentioned device is carried out according to the following process:

(1) Start the PN biochemical pool (2):

The water temperature of PN biochemical tank (2) is 30±1℃; the sludge concentration is MLSS is 4500±500mg/L, and the sludge return ratio is 300%; 2.9) Dissolved oxygen is 3.0～7.0mg/L; PN biochemical tank (2) feed water is leachate raw water, its total inorganic nitrogen concentration is 2000.0±200.0mg/L, NH ₄ ⁺ -N concentration is 1980.0±200.0mg/ L, COD is 3370.0±200.0mg/L; the pH of PN biochemical pool cell one (2.1) to PN biochemical pool cell four (2.4) is 7.6-7.8, PN biochemical pool cell five (2.5) to PN biochemical pool The pH of cell nine (2.9) is 7.2 to 7.8; the FA concentration of cell one (2.1) to cell four (2.4) of PN biochemical pool is 25.0 to 40.0 mg N/L, and cell five of PN biochemical cell (2.5) The FA concentration in the PN biochemical cell compartment nine (2.9) is 5.2-28.1 mg N/L; the FNA concentration in the PN biochemical cell compartment one (2.1) to the PN biochemical cell compartment four (2.4) is lower than 0.07 mg N/L, the FNA concentration of PN biochemical pool cell five (2.5) to PN biochemical pool cell nine (2.9) is lower than 0.22 mg N/L; operating under the above conditions, the effluent of PN biochemical pool (2) The accumulation rate of nitrate is greater than 90.0%, and the removal rate of NH ₄ ⁺ -N is greater than 60%; (2) The short-range nitrification coupled anammox PNA system is constructed:

Inoculate the biofilm carrier (5.23) with a relative abundance of anammox bacteria greater than 10.0% in the PNA biochemical tank (5), and fix the biofilm carrier (5.23) on the biofilm carrier fixing frame (5.24), the filling ratio is 20.0±2.0%; inoculate the excess sludge from the primary biochemical treatment into the PNA biochemical tank (5), so that the flocculent sludge concentration is 2000-2500 mg/L, and the sludge return ratio is 200%; the PNA biochemical tank (5) The water temperature is 30±1℃; the dissolved oxygen concentration of the PNA biochemical cell three (5.3), the PNA biochemical cell six (5.6) and the PNA biochemical cell nine (5.9) is 0.1～0.2mg/L; the second stage The regulating tank (4) is a 1:1 mixture of leachate raw water and primary biochemical treatment effluent. The mixture is continuously pumped into the PNA biochemical tank compartment 1 (5.1) at a flow ratio of 1:1:1. , PNA biochemical cell compartment four (5.4) and PNA biochemical cell compartment seven (5.7), and the influent nitrogen load increased from 0.02kg N/m ³ /d to 0.25kg N/m ³ /d; PNA biochemical cell compartment Chamber one, two, four, five, seven, eight (5.1, 5.2, 5.4, 5.5, 5.7, 5.8) pH 7.6 to 7.9, FA concentration 7.8 to 14.6 mg N/L, FNA concentration below 0.01 mg N/L L; PNA biochemical pool chambers three, six and nine (5.3, 5.6, 5.9) with pH of 6.9 to 7.2, FA concentration of 0 to 1.0 mg N/L, and FNA concentration of less than 0.005 mg N/L; run according to the above conditions , so that the total inorganic nitrogen concentration in the effluent of the PNA biochemical tank (5) is lower than 60.0 mg/L, the NH ₄ ⁺ -N concentration is lower than 10.0 mg/L, and the COD is lower than 2200 mg/L;

(3) PN biochemical pool (2), PNA biochemical pool (5) and DE biochemical pool (8) run in series:

The sodium acetate solution with a mass fraction of 15% enters the tertiary adjustment tank (7) through the external carbon source dosing pump (7.1) and the external carbon source dosing pipeline (7.2) and the effluent of the secondary biochemical treatment at a ratio of 1:550 to 1400. The flow ratio is mixed, the total inorganic nitrogen concentration in the three-stage regulating tank (7) is 30.0-60.0 mg/L, the NO ₃ ^- -N concentration is 20.0-50.0 mg/L; the sludge concentration in the DE biochemical tank (8) is 4000 mg/L. ±500mg/L, the sludge reflux ratio is 100%; the dissolved oxygen in the aerobic zone (8.9) of the DE biochemical tank is 2.0-3.0 mg/L, and the pH is 7.0-7.5; the pH in the anoxic zone (8.8) of the DE biochemical tank is At 7.5 to 8.0; operate according to the above conditions, so that the total inorganic nitrogen in the effluent of the tertiary biochemical treatment is lower than 15.0mg/L, and the NH ₄ ⁺ -N concentration is lower than 1.5mg/L;

(4) Start the effluent reflux:

The effluent from the tertiary biochemical treatment enters the primary regulating tank (1) through the effluent return pump (9.5) and the effluent return pipeline (9.6), and is mixed with the raw leachate water at a flow ratio of 1:1;

(5) Adjust the PN biochemical pool (2) operating parameters:

The water temperature of PN biochemical tank (2) is 30±1℃; the sludge concentration is MLSS of 4500±500mg/L, and the sludge return ratio is reduced from 300% to 200%; the influent of PN biochemical tank (2) is leachate raw water and The 1:1 mixed solution (1.2) of the third-stage biochemical treatment effluent has a total inorganic nitrogen concentration of 1000.0±100.0mg/L, NH ₄ ⁺ -N concentration of 990.0±100.0mg/L, and COD of 2700.0±200.0mg/L ; The pH of cell one (2.1) to cell four (2.4) of PN biochemical pool is 7.7-8.0, the FA concentration is 16.1-30.8 mg N/L, and the FNA concentration is lower than 0.02 mg N/L; The pH of cell five (2.5) to cell nine (2.9) of PN biochemical cell is 7.0-7.5, the FA concentration is 0.8-8.7 mg N/L, the FNA concentration is 0.03-0.17 mg N/L, and the dissolved oxygen is 3.0 ~7.0mg/L.

The device and method for treating late-stage landfill leachate provided by the novel continuous flow single-stage A/O process have the following features and advantages:

(1) Anoxic in-situ FA treatment and aerobic in-situ FNA treatment can effectively inhibit and wash NOB in the PN biochemical pool, ensuring a stable short-range nitrification effect.

(2) The strategy of returning the effluent from the tertiary biochemical treatment and mixing it with the leachate raw water effectively alleviated the inhibition of AOB and denitrifying bacteria by FA and FNA in the PN biochemical tank.

(3) The sectional influent strategy of PNA biochemical tank effectively alleviated the inhibition of FA on AnAOB, and also improved the utilization efficiency of influent organic matter.

(4) The coexistence of fixed biofilm and flocculent sludge in PNA biochemical tank promoted the effective retention of AnAOB and alleviated the impact of unfavorable environmental factors in this unit on AnAOB.

(5) The hierarchical setting of the PN biochemical pool, the PNA biochemical pool and the DE biochemical pool ensures that the anoxic area of the PNA biochemical pool has sufficient nitrite substrates, and realizes the deep removal of nitrates generated during the PNA process.

Description of drawings

Figure 1 is a schematic diagram of the device structure of the three-stage plug-flow PN-PNA-DE process for treating late-stage landfill leachate.

Among them, 1-first-level adjustment tank; 2-PN biochemical tank; 3-first-level sedimentation tank; 4-second-level adjustment tank; 5-PNA biochemical tank; 6-second-level sedimentation tank; 7-third-level adjustment tank; 8 —DE biochemical tank; 9—tertiary sedimentation tank; 1.1—leachate; 2.1—PN biochemical tank compartment one; 2.2—PN biochemical tank compartment two; 2.3—PN biochemical tank compartment three; 2.4—PN biochemical tank compartment Room four; 2.5—PN biochemical pool, five; 2.6—PN biochemical pool six; 2.7—PN biochemical pool seven; 2.8—PN biochemical pool eight; 2.9—PN biochemical pool nine; 2.10— 2.11—PN biochemical tank inlet water pipeline; 2.12—PN biochemical tank temperature control device; 2.13—PN biochemical tank heating device; 2.14—PN biochemical tank pH and DO real-time monitoring device; 2.15—PN biochemical tank machinery Stirrer; 2.16—PN biochemical tank aeration device; 2.17—PN biochemical tank gas flow meter; 2.18—PN biochemical tank microporous aeration plate; 2.19—PN biochemical tank outlet pipeline; 3.1—First-level biochemical treatment outlet pipeline ; 3.2—first-level sludge return pump; 3.3-first-level sludge return pipeline; 3.4-first-level biochemical treatment excess sludge discharge pipeline; 4.1-second-level adjustment tank inlet pump; Road; 4.3—first-level biochemical treatment effluent pump; 5.1—PNA biochemical tank compartment one; 5.2—PNA biochemical tank compartment two; 5.3—PNA biochemical tank compartment three; 5.4—PNA biochemical tank compartment four; 5.5—PNA biochemical tank compartment four Biochemical tank compartment five; 5.6—PNA biochemical tank compartment six; 5.7—PNA biochemical tank compartment seven; 5.8—PNA biochemical tank compartment eight; 5.9—PNA biochemical tank compartment nine; 5.10—PNA biochemical tank inlet pump one ;5.11—PNA biochemical pool inlet pipe one; 5.12—PNA biochemical tank inlet water pump two; 5.13—PNA biochemical tank water inlet pipe two; 5.14—PNA biochemical tank inlet water pump three; —PNA biochemical pool temperature control device; 5.17—PNA biochemical pool heating device; 5.18—PNA biochemical pool pH and DO real-time monitoring device; 5.19—PNA biochemical pool mechanical stirrer; 5.20—PNA biochemical pool aeration device; 5.21—PNA biochemical pool Pool gas flow meter; 5.22—PNA biochemical tank microporous aeration plate; 5.23—Biofilm carrier; 5.24—Biofilm carrier holder; 5.25—PNA biochemical tank outlet pipeline; 6.1—Secondary biochemical treatment outlet pipeline; 6.2 —Secondary sludge return pump; 6.3—Secondary sludge return pipeline; 7.1—External carbon source dosing pump; 7.2—External carbon source dosing pipeline; 8.1—DE biochemical tank inlet pump; 8.2—DE biochemical tank Water inlet pipeline; 8.3—DE biochemical tank pH and DO real-time monitoring device; 8.4—DE biochemical tank mechanical agitator; 8.5—DE biochemical tank aeration device; 8.6—DE biochemical tank gas flow 8.7—DE biochemical tank microporous aeration plate; 8.8—DE biochemical tank anoxic area; 8.9—DE biochemical tank aerobic area; 8.10—DE biochemical tank outlet pipeline; 9.1—three-stage biochemical treatment outlet pipeline 9.2—Three-stage biochemical treatment excess sludge discharge pipeline; 9.3—Three-stage sludge return pump; 9.4—Three-stage sludge return pipeline; 9.5—Effluent return pump; 9.6—Effluent return pipeline.

Detailed ways

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

As shown in Figure 1, the device for treating late-stage landfill leachate by the three-stage plug-flow PN-PNA-DE process includes: a first-stage regulating tank (1); a PN biochemical tank (2); a first-stage sedimentation tank (3); Level conditioning tank (4); PNA biochemical tank (5); Secondary sedimentation tank (6); Tertiary conditioning tank (7); DE biochemical tank (8); Tertiary sedimentation tank (9);

Among them, the PN biochemical tank inlet pump (2.10) continuously pumps the 1:1 mixture (1.2) of the leachate raw water and the tertiary biochemical treatment effluent from the first-level adjustment tank (1) through the PN biochemical tank inlet pipeline (2.11). PN biochemical tank compartment one (2.1) is mixed with activated sludge, and flows out from the PN biochemical tank compartment nine (2.9), into the PN biochemical tank outlet pipeline (2.19) and the first-level sedimentation tank (3); after precipitation, The supernatant liquid enters the secondary regulation tank (4) through the primary biochemical treatment effluent pump (4.3) and the primary biochemical treatment effluent pipeline (3.1), and the sludge in the primary sedimentation tank (3) returns through the primary sludge The pump (3.2) and the primary sludge return pipeline (3.3) are returned to the PN biochemical tank compartment 1 (2.1); the raw leachate water passes through the secondary conditioning tank inlet pump (4.1) and the secondary conditioning tank inlet pipeline (4.2). ) is pumped into the secondary regulating tank (4) and mixed with the effluent of the primary biochemical treatment; the mixed liquid in the secondary regulating tank (4) is passed through the PNA biochemical tank inlet pump one (5.10) and the PNA biochemical tank inlet pipeline one (5.11), PNA biochemical tank inlet pump two (5.12) and PNA biochemical tank inlet pipeline two (5.13), PNA biochemical tank inlet pump three (5.14) and PNA biochemical tank inlet pipeline three (5.15), respectively enter the PNA biochemical tank (5) PNA biochemical tank compartment one (5.1), PNA biochemical tank compartment four (5.4) and PNA biochemical tank compartment seven (5.7); ) into the secondary sedimentation tank (6); after precipitation, the supernatant in the secondary sedimentation tank (6) enters the tertiary adjustment tank (7) through the secondary biochemical treatment effluent pipeline (6.1); the secondary sedimentation tank (6) ) The bottom sludge is returned to the PNA biochemical tank compartment 1 (5.1) through the secondary sludge return pump (6.2) and the secondary sludge return pipeline (6.3); the sodium acetate solution is fed by the external carbon source pump (7.1) and the external carbon source feeding pipeline (7.2) enters the tertiary adjustment tank (7) and is mixed with the effluent of the secondary biochemical treatment; the mixed liquid in the tertiary adjustment tank (7) passes through the DE biochemical tank inlet pump (8.1) and the DE biochemical tank The water inlet pipeline (8.2) enters the front end of the anoxic zone (8.8) of the DE biochemical tank, and flows out from the end of the aerobic zone (8.9) of the DE biochemical tank, and enters the tertiary sedimentation tank (9) through the water outlet pipeline (8.10) of the DE biochemical tank. ; After precipitation, 50% of the supernatant enters the tertiary biochemical treatment effluent pipeline (9.1), and 50% of the supernatant enters the first-level adjustment tank (1) through the effluent return pump (9.5) and the effluent return pipeline (9.6); The sludge in the tertiary sedimentation tank (9) is returned to the anoxic zone (8.8) of the DE biochemical tank through the tertiary sludge return pump (9.3) and the tertiary sludge return pipeline (9.4);

In addition, the first-level adjustment tank (1) further includes a leachate raw water pipeline (1.1); the PN biochemical tank (2) further includes a PN biochemical tank compartment two (2.2), a PN biochemical tank compartment three (2.3) ), PN biochemical pool compartment four (2.4), PN biochemical pool compartment five (2.5), PN biochemical pool compartment six (2.6), PN biochemical pool compartment seven (2.7), PN biochemical pool compartment eight (2.8 ), PN biochemical pool temperature control device (2.12), PN biochemical pool heating device (2.13), PN biochemical pool pH and DO real-time monitoring device (2.14), PN biochemical pool mechanical stirrer (2.15), PN biochemical pool aeration device (2.16), PN biochemical tank gas flow meter (2.17), PN biochemical tank microporous aeration disc (2.18); the first-stage sedimentation tank also includes a first-stage biochemical treatment excess sludge discharge pipeline (3.4); the The PNA biochemical pool (5) also includes the PNA biochemical pool compartment two (5.2), the PNA biochemical pool compartment three, (5.3) the PNA biochemical pool compartment four (5.4), the PNA biochemical pool compartment five (5.5), the PNA biochemical pool compartment five (5.5), and the PNA biochemical pool compartment five (5.5). Cell six (5.6), PNA biochemical cell seven (5.7), PNA biochemical cell eight (5.8), PNA biochemical cell nine (5.9), PNA biochemical cell temperature control device (5.16), PNA biochemical cell Pool heating device (5.17), PNA biochemical pool pH and DO real-time monitoring device (5.18), PNA biochemical pool mechanical stirrer (5.19), PNA biochemical pool aeration device (5.20), PNA biochemical pool gas flow meter (5.21), PNA biochemical tank microporous aeration plate (5.22), biofilm carrier (5.23), biofilm carrier fixing frame (5.24); the DE biochemical tank (8) also includes a DE biochemical tank pH and DO real-time monitoring device (8.3) , DE biochemical pool mechanical stirrer (8.4), DE biochemical pool aeration device (8.5), DE biochemical pool gas flow meter (8.6), DE biochemical pool microporous aeration disc (8.7); the three-stage sedimentation tank ( 9) Also includes a tertiary biochemical treatment excess sludge discharge pipeline (9.2).

The method for late-stage landfill leachate treatment using the above-mentioned device is carried out according to the following process:

(1) Start the PN biochemical pool (2):

The water temperature of PN biochemical tank (2) is 30±1℃; the sludge concentration is MLSS is 4500±500mg/L, and the sludge return ratio is 300%; 2.9) Dissolved oxygen is 3.0～7.0mg/L; PN biochemical tank (2) feed water is leachate raw water, its total inorganic nitrogen concentration is 2000.0±200.0mg/L, NH ₄ ⁺ -N concentration is 1980.0±200.0mg/ L, COD is 3370.0±200.0mg/L; the pH of PN biochemical pool cell one (2.1) to PN biochemical pool cell four (2.4) is 7.6-7.8, PN biochemical pool cell five (2.5) to PN biochemical pool The pH of cell nine (2.9) is 7.2 to 7.8; the FA concentration of cell one (2.1) to cell four (2.4) of PN biochemical pool is 25.0 to 40.0 mg N/L, and cell five of PN biochemical cell (2.5) The FA concentration in the PN biochemical cell compartment nine (2.9) is 5.2-28.1 mg N/L; the FNA concentration in the PN biochemical cell compartment one (2.1) to the PN biochemical cell compartment four (2.4) is lower than 0.07 mg N/L, the FNA concentration of PN biochemical pool cell five (2.5) to PN biochemical pool cell nine (2.9) is lower than 0.22 mg N/L; operating under the above conditions, the effluent of PN biochemical pool (2) The accumulation rate of nitrate is greater than 90.0%, and the removal rate of NH ₄ ⁺ -N is greater than 60%; (2) The short-range nitrification coupled anammox PNA system is constructed:

Inoculate the biofilm carrier (5.23) with a relative abundance of anammox bacteria greater than 10.0% in the PNA biochemical tank (5), and fix the biofilm carrier (5.23) on the biofilm carrier fixing frame (5.24), the filling ratio is 20.0±2.0%; inoculate the excess sludge from the primary biochemical treatment into the PNA biochemical tank (5), so that the floc sludge concentration is 2000-2500 mg/L, and the sludge return ratio is 200%; the PNA biochemical tank (5) The water temperature is 30±1℃; the dissolved oxygen concentration of the PNA biochemical cell three (5.3), the PNA biochemical cell six (5.6) and the PNA biochemical cell nine (5.9) is 0.1～0.2mg/L; the second stage The regulating tank (4) is a 1:1 mixture of leachate raw water and primary biochemical treatment effluent. The mixture is continuously pumped into the PNA biochemical tank compartment 1 (5.1) at a flow ratio of 1:1:1. , PNA biochemical tank cell four (5.4) and PNA biochemical cell cell seven (5.7), and the influent nitrogen load increased from 0.02kg N/m ³ /d to 0.25kg N/m ³ /d, the purpose of the staged water inflow strategy It is to alleviate the inhibition of FA on AnAOB and improve the utilization efficiency of organic matter in the influent; PNA biochemical pool compartments one, two, four, five, seven, eight (5.1, 5.2, 5.4, 5.5, 5.7, 5.8) pH is 7.6 ～7.9, FA concentration is 7.8～14.6mg N/L, FNA concentration is lower than 0.01mg N/L; PNA biochemical cell chambers three, six, nine (5.3, 5.6, 5.9) pH is 6.9～7.2, FA concentration is 0～1.0mg N/L, the FNA concentration is lower than 0.005mg N/L; according to the above conditions, the total inorganic nitrogen concentration in the effluent of the PNA biochemical tank (5) is lower than 60.0mg/L, and the NH ₄ ⁺ -N concentration is low At 10.0mg/L, COD is lower than 2200mg/L; (3) PN biochemical pool (2), PNA biochemical pool (5) and DE biochemical pool (8) run in series:

The sodium acetate solution with a mass fraction of 15% enters the tertiary adjustment tank (7) through the external carbon source dosing pump (7.1) and the external carbon source dosing pipeline (7.2) and the effluent of the secondary biochemical treatment at a ratio of 1:550 to 1400. The flow ratio is mixed, the total inorganic nitrogen concentration in the three-stage regulating tank (7) is 30.0-60.0 mg/L, the NO ₃ ^- -N concentration is 20.0-50.0 mg/L; the sludge concentration in the DE biochemical tank (8) is 4000 mg/L. ±500mg/L, the sludge reflux ratio is 100%; the dissolved oxygen in the aerobic zone (8.9) of the DE biochemical tank is 2.0-3.0 mg/L, and the pH is 7.0-7.5; the pH in the anoxic zone (8.8) of the DE biochemical tank is At 7.5 to 8.0; operate according to the above conditions, so that the total inorganic nitrogen in the effluent of the tertiary biochemical treatment is lower than 15.0mg/L, and the NH ₄ ⁺ -N concentration is lower than 1.5mg/L;

(4) Start the system effluent backflow:

The effluent from the tertiary biochemical treatment enters the primary regulating tank (1) through the effluent return pump (9.5) and the effluent return pipeline (9.6), and is mixed with the raw leachate water at a flow ratio of 1:1, and is used as the inlet of the PN biochemical tank (2). water;

(5) PN biochemical pool (2) Adjustment of operating parameters:

The influent of PN biochemical tank (2) is a 1:1 mixture of leachate raw water and tertiary biochemical treatment effluent (1.2), the total inorganic nitrogen concentration is 1000.0±100.0mg/L, and the NH ₄ ⁺ -N concentration is 990.0± 100.0mg/L, COD is 2700.0±200.0mg/L, which is used to reduce the inhibition of FA on AOB and denitrifying bacteria; because the ammonia nitrogen concentration of the PN biochemical pool (2) influent is reduced, and the FA concentration of this unit is also reduced, so the pollution The mud reflux ratio is reduced from 300% to 200% to save energy; the pH of the PN biochemical tank cell one (2.1) to the PN biochemical cell cell four (2.4) is 7.7~8.0, and the FA concentration is 16.1~30.8mg N /L, FNA concentration is lower than 0.02mg N/L; pH of PN biochemical cell compartment five (2.5) to PN biochemical cell compartment nine (2.9) is 7.0～7.5, FA concentration is 0.8～8.7mg N/L, The concentration of FNA is 0.03-0.17 mg N/L, and the dissolved oxygen is 3.0-7.0 mg/L; according to the above conditions, the oxidation rate of ammonia nitrogen is greater than 90%, and the accumulation rate of nitrite is greater than 90.0%.

The experimental results show that: using the three-stage plug-flow PN-PNA-DE process device and method to treat late landfill leachate, when the total inorganic nitrogen concentration of the influent is 2000.0±200.0mg/L, and the NH ₄ ⁺ -N concentration is 1980.0 When the COD is ±200.0mg/L and the COD is 3370.0±200.0mg/L, the removal rates of total inorganic nitrogen, NH ₄ ⁺ -N and COD can reach 99.0%, 99.9% and 50.0%, respectively.

The device and method for treating late-stage landfill leachate by the three-stage plug-flow PN-PNA-DE process provided by the present invention have been described in detail above, and the principles and implementations of the present invention have been described with specific examples. It is only used to assist understanding of the method and core idea of the present invention. For those skilled in the art, according to the method and idea of the present invention, there will be changes in the specific embodiments. Therefore, the contents of this specification should not be construed as limiting the present invention.

Claims (2)

1. Device of three-stage plug flow type PN-PNA-DE process treatment late landfill leachate, its characterized in that: a primary regulating tank (1) is arranged; a PN biochemical pool (2); a primary sedimentation tank (3); a secondary regulating tank (4); a PNA biochemical pool (5); a secondary sedimentation tank (6); a third-stage regulating tank (7); a DE biochemical pool (8); a third-stage sedimentation tank (9);

wherein, a PN biochemical pool water inlet pump (2.10) continuously pumps mixed liquid (1.2) of raw leachate and three-stage biochemical treatment effluent 1:1 from a primary regulating pool (1) through a PN biochemical pool water inlet pipeline (2.11) into a PN biochemical pool cell I (2.1) to be mixed with activated sludge, and flows out of the PN biochemical pool cell II (2.9) to enter a PN biochemical pool water outlet pipeline (2.19) and a primary sedimentation pool (3); after precipitation, supernatant enters a secondary regulating tank (4) through a primary biochemical treatment water outlet pump (4.3) and a primary biochemical treatment water outlet pipeline (3.1), and sludge in the primary sedimentation tank (3) flows back to a PN biochemical pool grid chamber I (2.1) through a primary sludge return pump (3.2) and a primary sludge return pipeline (3.3); raw leachate is pumped into a secondary regulating reservoir (4) through a secondary regulating reservoir water inlet pump (4.1) and a secondary regulating reservoir water inlet pipeline (4.2) to be mixed with effluent of primary biochemical treatment; mixed liquid in the secondary regulating tank (4) respectively enters a PNA biochemical pool cell first (5.1), a PNA biochemical pool cell fourth (5.4) and a PNA biochemical pool cell seventh (5.7) of the PNA biochemical pool (5) through a PNA biochemical pool water inlet pump I (5.10) and a PNA biochemical pool water inlet pipeline I (5.11), a PNA biochemical pool water inlet pump II (5.12) and a PNA biochemical pool water inlet pipeline II (5.13), a PNA biochemical pool water inlet pump III (5.14) and a PNA biochemical pool water inlet pipeline III (5.15); the sludge-water mixed liquid of the PNA biochemical tank (5) enters a secondary sedimentation tank (6) through a PNA biochemical tank water outlet pipeline (5.25); after precipitation, supernatant in the secondary sedimentation tank (6) enters a tertiary regulating tank (7) through a secondary biochemical treatment water outlet pipeline (6.1); sludge at the bottom of the secondary sedimentation tank (6) flows back to a PNA biochemical tank cell I (5.1) through a secondary sludge return pump (6.2) and a secondary sludge return pipeline (6.3); sodium acetate solution enters a third-stage regulating tank (7) through an external carbon source feeding pump (7.1) and an external carbon source feeding pipeline (7.2) to be mixed with effluent of the second-stage biochemical treatment; the mixed liquid in the third-stage regulating tank (7) enters the front end of an anoxic zone (8.8) of the DE biochemical tank through a DE biochemical tank water inlet pump (8.1) and a DE biochemical tank water inlet pipeline (8.2), and is discharged from the tail end of an aerobic zone (8.9) of the DE biochemical tank and enters a third-stage sedimentation tank (9) through a DE biochemical tank water outlet pipeline (8.10); after precipitation, 50% of the supernatant enters a water outlet pipeline (9.1) of the three-stage biochemical treatment, and 50% of the supernatant enters a first-stage regulating tank (1) through a water outlet reflux pump (9.5) and a water outlet reflux pipeline (9.6); the sludge in the third-stage sedimentation tank (9) flows back to an anoxic zone (8.8) of the DE biochemical tank through a third-stage sludge return pump (9.3) and a third-stage sludge return pipeline (9.4);

in addition, the primary regulating tank (1) also comprises a percolate raw water pipeline (1.1); the PN biochemical pool (2) further comprises a PN biochemical pool cell II (2.2), a PN biochemical pool cell III (2.3), a PN biochemical pool cell IV (2.4), a PN biochemical pool cell V (2.5), a PN biochemical pool cell VI (2.6), a PN biochemical pool cell seven (2.7), a PN biochemical pool cell eight (2.8), a PN biochemical pool temperature control device (2.12), a PN biochemical pool heating device (2.13), a PN biochemical pool pH and DO real-time monitoring device (2.14), a PN biochemical pool mechanical stirrer (2.15), a PN biochemical pool aeration device (2.16), a PN biochemical pool gas flow meter (2.17) and a PN biochemical pool microporous aeration disc (2.18); the primary sedimentation tank also comprises a primary biochemical treatment residual sludge discharge pipeline (3.4); the PNA biochemical pool (5) further comprises a PNA biochemical pool cell II (5.2), a PNA biochemical pool cell III (5.3), a PNA biochemical pool cell IV (5.4), a PNA biochemical pool cell V (5.5), a PNA biochemical pool cell VI (5.6), a PNA biochemical pool cell VII (5.7), a PNA biochemical pool cell VIII (5.8), a PNA biochemical pool cell nine (5.9), a PNA biochemical pool temperature control device (5.16), a PNA biochemical pool heating device (5.17), a PNA biochemical pool pH and DO real-time monitoring device (5.18), a PNA biochemical pool mechanical stirrer (5.19), a PNA biochemical pool aeration device (5.20), a biochemical PNA pool gas flow meter (5.21), a PNA biochemical pool microporous aeration disc (5.22), a biological membrane carrier (5.23) and a biological membrane carrier fixing frame (5.24); the DE biochemical tank (8) further comprises a pH and DO real-time monitoring device (8.3) of the DE biochemical tank, a mechanical stirrer (8.4) of the DE biochemical tank, an aeration device (8.5) of the DE biochemical tank, a gas flowmeter (8.6) of the DE biochemical tank and a microporous aeration disc (8.7) of the DE biochemical tank; the three-stage sedimentation tank (9) also comprises a three-stage biochemical treatment residual sludge discharge pipeline (9.2).

2. The method for treating the landfill leachate at the late stage by using the device of claim 1 and adopting the three-stage plug-flow PN-PNA-DE process is characterized by comprising the following steps of:

(1) starting the PN biochemical pool (2):

the water temperature of the PN biochemical pool (2) is 30 +/-1 ℃; the sludge concentration is that MLSS is 4500 + -500 mg/L, the sludge reflux ratio is 300%; dissolved oxygen from PN biochemical pool cell five (2.5) to PN biochemical pool cell nine (2.9) is 3.0-7.0 mg/L; the inlet water of the PN biochemical pool (2) is leachate raw water, the total inorganic nitrogen concentration is 2000.0 +/-200.0 mg/L, and NH₄ ⁺The concentration of N is 1980.0 +/-200.0 mg/L, and the COD is 3370.0 +/-200.0 mg/L; the pH value from PN biochemical pool cell I (2.1) to PN biochemical pool cell IV (2.4) is 7.6-7.8, and the pH value from PN biochemical pool cell V (2.5) to PN biochemical pool cell VI (2.9) is 7.2-7.8; the FA concentration from the PN biochemical pool cell I (2.1) to the PN biochemical pool cell IV (2.4) is 25.0-40.0 mg N/L, and the FA concentration from the PN biochemical pool cell V (2.5) to the PN biochemical pool cell nine (2.9) is 5.2-28.1 mg N/L; the FNA concentration of PN biochemical cell I (2.1) to PN biochemical cell IV (2.4) is lower than 0.07mg N/L, and the FNA concentration of PN biochemical cell V (2.5) to PN biochemical cell VI (2.9) is lower than 0.22mg N/L; push buttonThe conditions are operated, so that the effluent nitrite accumulation rate of the PN biochemical pool (2) is more than 90.0 percent, and NH is added₄ ⁺-N removal greater than 60%;

(2) constructing a shortcut nitrification coupled anaerobic ammonia oxidation PNA system:

a biomembrane carrier (5.23) with the relative abundance of anaerobic ammonium oxidation bacteria of more than 10.0 percent is inoculated in the PNA biochemical pool (5), and the biomembrane carrier (5.23) is fixed on a biomembrane carrier fixing frame (5.24), and the filling ratio is 20.0 +/-2.0 percent; inoculating the residual sludge subjected to the primary biochemical treatment into a PNA biochemical tank (5) to ensure that the concentration of floc sludge is 2000-2500 mg/L and the reflux ratio of the sludge is 200%; the water temperature of the PNA biochemical pool (5) is 30 +/-1 ℃; the dissolved oxygen concentration of PNA biochemical pool cell III (5.3), PNA biochemical pool cell VI (5.6) and PNA biochemical pool cell nine (5.9) is 0.1-0.2 mg/L; the secondary regulating tank (4) is internally provided with raw water of percolate and effluent of primary biochemical treatment 1:1, the mixed solution is continuously pumped into a first PNA biochemical pool cell (5.1), a fourth PNA biochemical pool cell (5.4) and a seventh PNA biochemical pool cell (5.7) in sections according to the flow ratio of 1:1:1, and the load of inlet water nitrogen is from 0.02kg N/m³Increasing the volume of/d to 0.25kg N/m³D; PNA biochemical pool cell I, II, IV, V, VII, VIII (5.1, 5.2, 5.4, 5.5, 5.7, 5.8) pH is 7.6-7.9, FA concentration is 7.8-14.6 mg N/L, FNA concentration is lower than 0.01mg N/L; PNA biochemical pool cell three, six, nine (5.3, 5.6, 5.9) pH 6.9 ~ 7.2, FA concentration 0 ~ 1.0mg N/L, FNA concentration is less than 0.005mg N/L; the operation is carried out according to the conditions, so that the total inorganic nitrogen concentration in the effluent of the PNA biochemical pool (5) is lower than 60.0mg/L, and NH is generated₄ ⁺-N concentration lower than 10.0mg/L, COD lower than 2200 mg/L;

(3) PN biochemical pool (2), PNA biochemical pool (5) and DE biochemical pool (8) are connected in series for operation:

sodium acetate solution with mass fraction of 15% enters a third-stage regulating tank (7) through an external carbon source feeding pump (7.1) and an external carbon source feeding pipeline (7.2) and is mixed with secondary biochemical treatment effluent in a flow ratio of 1: 550-1400, the total inorganic nitrogen concentration in the third-stage regulating tank (7) is 30.0-60.0 mg/L, NO is added into the third-stage regulating tank (7), and the total inorganic nitrogen concentration is 30.0-60.0 mg/L₃ ^-The concentration of-N is 20.0-50.0 mg/L; the sludge concentration of the DE biochemical pool (8) is 4000 +/-500 mg/L, and the sludge reflux ratio is 100 percent; dissolved oxygen in an aerobic zone (8.9) of the DE biochemical pool is 2.0-3.0 mg/L, and the pH value is7.0 to 7.5; the pH value of an anoxic zone (8.8) of the DE biochemical pool is 7.5-8.0; the operation is carried out according to the conditions, so that the total inorganic nitrogen of the effluent of the three-stage biochemical treatment is lower than 15.0mg/L and NH₄ ⁺-N concentration lower than 1.5 mg/L;

(4) starting effluent backflow:

the effluent of the three-stage biochemical treatment enters a first-stage regulating reservoir (1) through an effluent reflux pump (9.5) and an effluent reflux pipeline (9.6), and the raw water of the percolate is 1: mixing at a flow ratio of 1;

(5) adjusting the operation parameters of the PN biochemical pool (2):

the water temperature of the PN biochemical pool (2) is 30 +/-1 ℃; the sludge concentration is that MLSS is 4500 + -500 mg/L, the sludge reflux ratio is reduced from 300% to 200%; the inlet water of the PN biochemical pool (2) is mixed liquid (1.2) of raw leachate and 1:1 of effluent of the third-level biochemical treatment, the total inorganic nitrogen concentration is 1000.0 +/-100.0 mg/L, and NH₄ ⁺The concentration of N is 990.0 +/-100.0 mg/L, and the COD is 2700.0 +/-200.0 mg/L; the pH value from the first PN biochemical cell (2.1) to the fourth PN biochemical cell (2.4) is 7.7-8.0, the FA concentration is 16.1-30.8 mg N/L, and the FNA concentration is lower than 0.02mg N/L; the pH value from the fifth (2.5) of the PN biochemical cell to the ninth (2.9) of the PN biochemical cell is 7.0-7.5, the FA concentration is 0.8-8.7 mg N/L, the FNA concentration is 0.03-0.17 mg N/L, and the dissolved oxygen is 3.0-7.0 mg/L.

Images