WO2023045069A1

WO2023045069A1 - Device and method for treating urban domestic wastewater based on short-range denitrification-anammox two-stage combined process

Info

Publication number: WO2023045069A1
Application number: PCT/CN2021/133875
Authority: WO
Inventors: 王博; 马雨晴; 李笑迪; 王硕; 汪文; 江潭
Original assignee: 北京工业大学
Priority date: 2021-09-27
Filing date: 2021-11-29
Publication date: 2023-03-30
Also published as: CN113800637B; CN113800637A

Abstract

The present invention belongs to the field of wastewater biological treatment, and disclosed are a device and method for treating urban domestic wastewater based on a short-range denitrification-anammox two-stage combined process. The device comprises a raw water tank, a sequencing batch biofilm reactor (SBBR), an intermediate water tank, an upflow anaerobic sludge blanket (UASB), and an outlet water tank. A portion of urban domestic wastewater enters the SBBR and is mixed with the remaining wastewater from a previous cycle. A short-range denitrification-anammox reaction is carried out under stirring conditions to remove nitrate nitrogen and some ammonia nitrogen. Then, full nitrification is carried out under aeration conditions to convert all ammonia nitrogen into nitrate nitrogen, and effluent water enters the intermediate water tank. The other portion of urban domestic wastewater is mixed with the effluent water of the SBBR and continuously enters the UASB, and nitrite nitrogen and ammonia nitrogen produced by the reduction of nitrate nitrogen are removed by means of anaerobic ammonium oxidation. According to the present invention, organic matter in wastewater may be effectively removed without adding external carbon sources, which improves the denitrification efficiency of urban domestic wastewater, and achieves high-efficiency and low-consumption denitrification.

Description

Device and method for treating urban domestic sewage based on short-range denitrification-anammox two-stage combined process

technical field

The device and method for treating urban domestic sewage based on the short-range denitrification-anammox two-stage combined process of the present invention belong to the field of sewage biological treatment and are suitable for deep denitrification of urban domestic sewage with low C/N ratio.

Background technique

In the process of urban domestic sewage treatment, nitrification-denitrification technology is commonly used in sewage treatment plants today. However, due to the low carbon and nitrogen in urban domestic sewage, nitrification-denitrification requires more carbon sources, resulting in denitrification. Nitrogen efficiency is not high, so it is often necessary to add additional carbon sources, which does not meet the requirements of sustainable development.

In recent years, the anaerobic ammonium oxidation process has received widespread attention due to its energy-saving characteristics. This reaction uses nitrite as an electron acceptor to oxidize ammonia nitrogen into nitrogen for denitrification, and at the same time produces 11% nitrate nitrogen. The reaction is carried out under anaerobic conditions without a carbon source, which meets the requirements of sustainable development. However, there are still difficulties in the application of anammox reaction to denitrification of urban domestic sewage. For example, anammox bacteria grow slowly, have a long generation cycle, and are sensitive to the environment; the supply of nitrite is unstable; at the same time, anammox reaction will produce A small amount of nitrate nitrogen makes it difficult to achieve deep denitrification of sewage.

Both short-cut nitrification and short-cut denitrification can be used as a way to produce nitrite, so the two are usually used in combination with anammox reaction. If anammox is combined with short-range nitrification, although it can save carbon source dosage and aeration, it will still produce about 11% nitrate nitrogen and need to increase carbon capture pretreatment before the process to help remove organic matter; Complex control, difficult to stabilize elutriation/inhibition of NOB. However, if anammox is combined with short-range denitrification, while saving carbon sources, the nitrate nitrogen produced by anammox can be further removed through denitrification, and theoretically 100% denitrification can be achieved; The supply of nitrate nitrogen is more stable.

Therefore, the present invention has developed a two-stage denitrification process based on short-range denitrification-ANAMMOX reaction, which can realize efficient utilization of organic matter in domestic sewage while improving the denitrification performance of the system; in addition, it has low energy consumption and low treatment cost. low advantage.

Contents of the invention

The present invention provides a device and method for treating urban domestic sewage based on a short-range denitrification-ANAMMOX two-stage combined process, with the purpose of solving the problem of insufficient carbon sources in the traditional sewage treatment process and improving the denitrification rate at the same time .

A device for treating urban domestic sewage based on a short-range denitrification-anammox two-stage combined process, characterized in that:

It is equipped with raw water tank (1), SBBR (2), intermediate water tank (3), UASB (4), and water outlet tank (5); the raw water tank (1) is equipped with water inlet pump Ⅰ (1.1) and water inlet pump Ⅱ (1.2) ;SBBR(2) is equipped with stirring device (2.1), gas flow meter (2.2), aeration pump (2.3), aeration disc (2.4), pH probe (2.5), DO probe (2.6), packing frame (2.7 ), filler (2.8), drain valve (2.9); middle water tank (3) is equipped with water inlet pump Ⅲ (3.1); UASB reactor (4) is equipped with pH probe (4.1), DO probe (4.2), water inlet ( 4.3), gas collection port (4.4) and water outlet (4.5);

The raw water tank (1) is connected to the water inlet of the SBBR (2) through the water inlet pump I (1.1), and connected to the water inlet (4.4) of the UASB (4) through the water inlet pump II (1.2); the SBBR (2) is connected through the drain valve ( 2.9) Connected to the intermediate water tank (3); UASB (4) water inlet (4.3) is connected to the intermediate water tank (3) through the water inlet pump Ⅲ (3.1); UASB (4) is connected to the water outlet bucket (5) through the water outlet (4.5) connected.

The method for using the device to treat urban domestic sewage based on a short-range denitrification-ANAMMOX two-stage combined process is characterized in that it includes the following steps:

1) SBBR start:

1.1) Start of short-range denitrification-nitrification reaction: use the whole process of nitrification sludge from the actual urban sewage treatment plant as inoculation sludge to inject into SBBR (2), the sludge concentration is 2500-4000mg/L; use artificial wastewater as influent, artificial wastewater The concentration of NH ₄ ⁺ -N in the medium is 40-60mg/L, and the concentration of COD is 200-300mg/L; inject the SBBR (2) through the water inlet pump II (1.2), and the water inlet time is 5-10min; run the SBBR stirring device (2.1 ) to achieve full mixing of mud and liquid, the stirring time is 40-80min; start the aeration pump (2.2) to aerate for 60-80min, DO is maintained at 0.3-0.5mg/L during aeration, and the pH value is maintained at 6.5-8.5; after that Precipitate for 20-30min, carry out drainage for 5-10min, the SBBR drainage ratio is 0.3-0.5, discharge the supernatant into the intermediate water tank (3); the reactor runs 6-8 cycles per day, and there is an idle period of 30-110min in each cycle Time; when the short-range denitrification phenomenon occurs in the stirring stage of the reactor, there is 5-10mg/L of nitrite nitrogen, and the ammonia oxidation rate in the subsequent aeration stage reaches more than 90%, that is, the concentration of nitrate nitrogen is 20-30mg/L, which can maintain 10 days or more is considered to be completed;

1.2) Anammox reaction starts: inoculate the anammox bacteria attached to the filler (2.7) in the SBBR (2); the filler (2.7) filling ratio is 20%-30% of the SBBR; while prolonging the stirring time, Make the SBBR reactor (2) operate according to the mode of water inflow for 5-10min, stirring for 140-220min, aeration for 60-80min, sedimentation for 20-30min, water outlet for 5-10min, and idle for 10min. DO is maintained at 0.3-0.5mg/L, and the pH value is maintained at 6.5-8.5; when the stirring in the SBBR ends, the concentration of ammonia nitrogen drops by 5-10mg/L compared with the concentration of ammonia nitrogen at the beginning of stirring, and the concentration of nitrate nitrogen decreases to 1mg/L or less, and the ammonia oxidation rate of the remaining ammonia nitrogen after the aeration stage is over 90%, that is, when the nitrate nitrogen concentration is 10-20mg/L, the start-up is considered successful;

2) UASB start: while starting SBBR, start UASB (4); inoculate sludge in UASB (4) to be the sludge in the short-range denitrification-anammox reactor of long-term operation, the sludge after inoculation Concentration 2000-3000mg/L; UASB (4) influent is divided into two parts, one part is SBBR (2) nitrate nitrogen effluent, the other part is artificial wastewater NH ₄ ⁺ -N concentration is 40-60mg/L, COD concentration 200-300mg/L, the two enter the UASB (4) according to the volume ratio of 2:1-3:1, control the concentration of ammonia nitrogen in the influent of UASB (4) to 10-20mg/L, and the concentration of nitrate nitrogen to 10-20mg /L; the hydraulic retention time is 180-240min; the sludge is not actively discharged during the operation, and the startup is considered successful when the ammonia nitrogen and nitrate nitrogen in the effluent drop by more than 5mg/L.

3) SBBR-UASB operation: SBBR reactor (2) maintains water intake for 5-10 minutes, stirs for 140-220 minutes, aerates for 60-80 minutes, settles for 20-30 minutes, discharges water for 5-10 minutes, and runs idle for 10 minutes. It runs 4 times a day -6 cycles; DO is maintained at 0.3-0.5mg/L during aeration; UASB operates continuously according to the volume ratio of artificial wastewater and SBBR nitrate-containing effluent 2:1-3:1, when the total nitrogen in the effluent drops to Below 5mg/L, the denitrification is considered successful.

In summary, the device and method for treating urban domestic sewage based on the short-range denitrification-ANAMMOX two-stage combined process is as follows: the artificial wastewater enters the SBBR from the water inlet device, and denitrification and short-range denitrification occur during the stirring stage. Denitrification, consumes organic matter, converts the remaining nitrate nitrogen in the previous cycle into most of nitrogen and a part of nitrite nitrogen, and then produces nitrite nitrogen and part of ammonia nitrogen to undergo anaerobic ammonium oxidation reaction; then the remaining ammonia nitrogen in the aeration stage is nitrified Under the action of bacteria, it is transformed into nitrate nitrogen and discharged into the middle water tank as part of the water intake of UASB; artificial wastewater and SBBR nitrate-nitrogen-containing effluent enter the UASB in proportion, and short-range denitrification occurs to consume part of the organic matter and convert nitrate nitrogen into nitrite Then, the nitrite nitrogen and ammonia nitrogen are removed through anammox reaction, and the nitrate nitrogen produced can be converted into nitrite through short-range denitrification, and then provide a substrate for anammox.

Compared with the prior art, the present invention has the following advantages:

(1) Make full use of organic matter in water as a carbon source to convert nitrate nitrogen into nitrous to provide substrates for anammox;

(2) By-products of anaerobic ammonium oxidation are effectively utilized through short-range denitrification to improve nitrogen removal efficiency;

(3) The whole process of nitrification plus short-range denitrification provides nitrite nitrogen substrates to make the system more stable.

Description of drawings

Fig. 1 is device structural diagram of the present invention:

In the figure, there are raw water tank (1), SBBR (2), intermediate water tank (3), UASB (4), and water outlet tank (5); the raw water tank (1) is equipped with water inlet pump Ⅰ (1.1) and water inlet pump Ⅱ ( 1.2); SBBR (2) is equipped with stirring device (2.1), gas flow meter (2.2), aeration pump (2.3), aeration disc (2.4), pH probe (2.5), DO probe (2.6), packing frame (2.7), filler (2.8), drain valve (2.9); middle water tank (3) is equipped with inlet pump III (3.1); UASB reactor (4) is equipped with pH probe (4.1), DO probe (4.2), inlet Water port (4.3), air collecting port (4.4) and water outlet (4.5);

Preferred Embodiments of the Invention

With reference to the test device shown in Figure 1, implement according to the following steps:

1) Start-up of SBBR: 1.1) Start-up of short-range denitrification-nitrification reaction: use the whole process of nitrification sludge from the actual urban sewage treatment plant as inoculation sludge to inject into SBBR (2), and the sludge concentration is 3000mg/L; use artificial wastewater as influent , the NH ₄ ⁺ -N concentration in the artificial wastewater is 60mg/L, and the COD concentration is 250mg/L; the SBBR (2) is injected into the SBBR (2) through the water inlet pump II (1.2), and the water inlet time is 5min; the SBBR stirring device (2.1) is operated to realize The mud liquid is fully mixed, and the stirring time is 60 minutes; the aeration pump (2.2) is started to aerate for 60 minutes, and the DO is maintained at 0.5 mg/L during aeration, and the pH value is maintained at 6.5-8.5; after 30 minutes of sedimentation, drainage is carried out for 5 minutes, SBBR The drainage ratio is 0.5, and the supernatant is discharged into the intermediate water tank (3); the reactor runs 8 cycles a day, and there is an idle time of 80 minutes in each cycle; -10mg/L of nitrite nitrogen, the ammonia oxidation rate in the subsequent aeration stage reaches more than 90%, that is, the nitrate nitrogen concentration is below 30mg/L, and can maintain stable operation for more than 10 days;

1.2) Anammox reaction start: Inoculate the anammox bacteria attached to the filler (2.7) in the SBBR (2); the filling ratio of the filler (2.7) is 20% of the SBBR; simultaneously prolong the time of stirring and aeration , make the SBBR reactor (2) operate according to the mode of water intake for 5min, stirring for 220min, aeration for 80min, sedimentation for 30min, water outlet for 5min, and idle for 40min, 4 cycles per day; DO is kept at 0.3mg/L during aeration, pH The value is maintained at 6.5-8.5; when the stirring in the SBBR ends, the ammonia nitrogen concentration drops by 5-10mg/L compared with the beginning of the stirring, and the nitrate nitrogen is completely removed, and the ammonia oxidation rate of the remaining ammonia nitrogen reaches 90% after the aeration stage % or more means that the concentration of nitrate nitrogen reaches 20-25mg/L;

2) UASB start: while starting SBBR, start UASB (4); inoculate sludge in UASB (4) to be the sludge in the short-range denitrification-anammox reactor of long-term operation, the sludge after inoculation The concentration is 2000mg/L; UASB (4) influent is divided into two parts, one part is the effluent of SBBR (2) containing nitrate nitrogen, and the other part is artificial wastewater. The concentration of NH4+-N in the artificial wastewater is 60mg/L, and the concentration of COD is 250mg/L, the two enter the UASB (4) at a volume ratio of 3:1, so that the concentrations of ammonia nitrogen and nitrate nitrogen in the UASB (4) influent are both 20-25mg/L; the hydraulic retention time is 360min; the operation process The sludge is not actively discharged in the middle; after a period of operation, the ammonia nitrogen and nitrate nitrogen in the UASB effluent appear to decrease;

3) SBBR-UASB operation: SBBR reactor (2) keeps water inflow for 5 minutes, stirs for 220 minutes, aerates for 80 minutes, DO is kept at 0.3 mg/L during aeration, settles for 30 minutes, effluents for 5 minutes, idles for 10 minutes, and runs every day 4 cycles; UASB operates continuously according to the 3:1 volume ratio of artificial wastewater and SBBR nitrate-containing effluent. When the total nitrogen in the effluent drops from 40mg/L-50mg/L to below 5 mg/L, urban life is realized. Wastewater was successfully denitrified.

Claims

A device for treating urban domestic sewage based on a short-range denitrification-anammox two-stage combined process, characterized in that:

It is equipped with raw water tank (1), SBBR (2), intermediate water tank (3), UASB (4), and outlet water tank (5);

Raw water tank (1) is equipped with water inlet pump Ⅰ (1.1) and water inlet pump Ⅱ (1.2); SBBR (2) is equipped with stirring device (2.1), gas flow meter (2.2), aeration pump (2.3), aeration plate (2.4), pH probe (2.5), DO probe (2.6), packing frame (2.7), packing (2.8), drain valve (2.9); intermediate water tank (3) is equipped with water inlet pump Ⅲ (3.1); UASB reactor (4) Equipped with pH probe (4.1), DO probe (4.2), water inlet (4.3), gas collection port (4.4) and water outlet (4.5);

The raw water tank (1) is connected to the water inlet of the SBBR (2) through the water inlet pump I (1.1), and connected to the water inlet (4.4) of the UASB (4) through the water inlet pump II (1.2); the SBBR (2) is connected through the drain valve ( 2.9) Connected to the intermediate water tank (3); UASB (4) water inlet (4.3) is connected to the intermediate water tank (3) through the water inlet pump Ⅲ (3.1); UASB (4) is connected to the water outlet bucket (5) through the water outlet (4.5) connected.
Applying the device described in claim 1 to carry out a method for treating urban domestic sewage based on a short-range denitrification-ANAMMOX two-stage combination process, is characterized in that, comprising the following steps:

1) SBBR start:

1.1) Start of short-range denitrification-nitrification reaction: use the whole process of nitrification sludge from the actual urban sewage treatment plant as inoculation sludge to inject into SBBR (2), the sludge concentration is 2500-4000mg/L; use artificial wastewater as influent, artificial wastewater The concentration of NH 4 + -N in the medium is 40-60mg/L, and the concentration of COD is 200-300mg/L; inject the SBBR (2) through the water inlet pump II (1.2), and the water inlet time is 5-10min; run the SBBR stirring device (2.1 ) to achieve full mixing of mud and liquid, the stirring time is 40-80min; start the aeration pump (2.2) to aerate for 60-80min, DO is maintained at 0.3-0.5mg/L during aeration, and the pH value is maintained at 6.5-8.5; after that Precipitate for 20-30min, carry out drainage for 5-10min, the SBBR drainage ratio is 0.3-0.5, discharge the supernatant into the intermediate water tank (3); the reactor runs 6-8 cycles per day, and there is an idle period of 30-110min in each cycle Time; when the short-range denitrification phenomenon occurs in the stirring stage of the reactor, there is 5-10mg/L of nitrite nitrogen, and the ammonia oxidation rate in the subsequent aeration stage reaches more than 90%, that is, the concentration of nitrate nitrogen is 20-30mg/L, which can maintain 10 days or more is considered to be completed;

1.2) Anammox reaction starts: inoculate the anammox bacteria attached to the filler (2.7) in the SBBR (2); the filler (2.7) filling ratio is 20%-30% of the SBBR; while prolonging the stirring time, Make the SBBR reactor (2) operate according to the mode of water inflow for 5-10min, stirring for 140-220min, aeration for 60-80min, sedimentation for 20-30min, water outlet for 5-10min, and idle for 10min. DO is maintained at 0.3-0.5mg/L, and the pH value is maintained at 6.5-8.5; when the stirring in the SBBR ends, the concentration of ammonia nitrogen drops by 5-10mg/L compared with the concentration of ammonia nitrogen at the beginning of stirring, and the concentration of nitrate nitrogen decreases to 1mg/L or less, and the ammonia oxidation rate of the remaining ammonia nitrogen after the aeration stage is over 90%, that is, when the nitrate nitrogen concentration is 10-20mg/L, the start-up is considered successful;

2) UASB start: while starting SBBR, start UASB (4); inoculate sludge in UASB (4) to be the sludge in the short-range denitrification-anammox reactor of long-term operation, the sludge after inoculation The concentration is 2000-3000mg/L; UASB (4) influent is divided into two parts, one part is SBBR (2) nitrate nitrogen effluent, the other part is artificial wastewater NH 4 + -N concentration is 40-60mg/L, COD The concentration is 200-300mg/L, and the two enter the UASB (4) according to the volume ratio of 2:1-3:1. 20mg/L; the hydraulic retention time is 180-240min; during the operation, the sludge is not actively discharged, and the startup is considered successful when the ammonia nitrogen and nitrate nitrogen in the effluent drop by more than 5mg/L;

3) SBBR-UASB operation: SBBR reactor (2) maintains water intake for 5-10 minutes, stirs for 140-220 minutes, aerates for 60-80 minutes, settles for 20-30 minutes, discharges water for 5-10 minutes, and runs idle for 10 minutes. It runs 4 times a day -6 cycles; DO is maintained at 0.3-0.5mg/L during aeration; UASB operates continuously according to the volume ratio of artificial wastewater and SBBR nitrate-containing effluent 2:1-3:1, when the total nitrogen in the effluent drops to Below 5mg/L, the denitrification is considered successful.