CN108408897B - Integrated short-cut nitrification anaerobic ammonia oxidation and phosphorus removal intermittent aeration real-time control method - Google Patents

Abstract

The invention discloses an intermittent aeration real-time control method of integrated short-range nitrification anammox and phosphorus removal at the same time, belonging to the field of sewage biological treatment. 1. Pump the original domestic sewage into the integrated reactor 2. The intermittent aeration process adopts periodic anoxic stirring for 22 minutes, followed by hypoxia aeration for 8 minutes, and the dissolved oxygen is 0.8-1.2 mg/L. A total of intermittent aeration 11 cycles; 3. The water is effluent after precipitation, the hydraulic retention time is 6h per cycle, and the floc sludge age is 30-50d. This method utilizes the different sensitivities of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) to intermittent aeration, so that AOB is in a dominant position; the control of low oxygen aeration time and sludge age further realizes AOB Long-term maintenance of dominant bacterial species status. At the same time, due to the direct access to the original domestic sewage, the period of intermittent aeration is long, and zero addition of external carbon sources and deep denitrification and phosphorus removal are realized. The invention has the advantages of precise control, zero carbon source addition, short-range nitrification, anaerobic ammonia oxidation, and simultaneous phosphorus removal.

Description

Intermittent aeration real-time control of integrated short-range nitrification and anammox simultaneous phosphorus removal method

technical field

The invention relates to an intermittent aeration real-time control method for integrated short-range nitrification anaerobic ammonia oxidation and phosphorus removal at the same time, and belongs to the technical field of sewage biological treatment.

Background technique

Due to the current serious eutrophication of water bodies, many sewage treatment plants are upgrading and upgrading, and the indicators of total nitrogen and phosphorus in the effluent are more stringent. This requires an energy-saving and efficient denitrification and phosphorus removal process to be put into the upgrading and renovation project of the sewage treatment plant. At present, most sewage treatment plants still operate according to the traditional AAO or oxidation ditch mode. It is difficult for the total nitrogen and total phosphorus in the effluent to reach the standard, and it also faces many obstacles such as low temperature, low energy and large water volume of urban domestic sewage. At the same time, sewage treatment is an energy-intensive industry. On the one hand, high energy consumption leads to an increase in the cost of sewage treatment, which aggravates the current energy crisis in my country to a certain extent. On the other hand, the high treatment cost caused by high energy consumption has caused some small and medium-sized sewage treatment It is difficult for the plant to operate normally, and the emission reduction benefits of the sewage treatment plant cannot be brought into full play. Therefore, being able to make full use of the carbon source in urban domestic sewage without the need for an external carbon source for efficient denitrification and phosphorus removal has become the goal pursued in the field of sewage treatment.

The current deep denitrification technologies mainly include the coupling of short-range nitrification and denitrification, simultaneous nitrification and denitrification, and anammox. Nitrifying bacteria are a class of chemotrophic bacteria, mainly including ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB), which can convert NH ₄ ⁺ into NO ₂ ^- and NO ₂ ^- into NO ₃ ^- , plays an irreplaceable role in the denitrification process of sewage. The short-range denitrification technology is to control the biological nitrification process in the ammonia oxidation stage, and then directly carry out denitrification, thereby achieving the purpose of energy saving and consumption reduction. Short-range nitrification is the key to short-range denitrification technology, and the key to realizing short-range nitrification lies in the enrichment of AOB and the inhibition and elutriation of NOB.

At present, the methods used to achieve short-range nitrification mainly include high temperature, high pH value, high concentration of free ammonia (FA) and high concentration of free nitrous acid (FNA), low dissolved oxygen (DO), short sludge age (SRT), and Add inhibitors, etc. The above short-range nitrification methods are all to create an environment suitable for AOB growth, inhibit or slow down NOB growth during system operation, and gradually form a short-range denitrification system in which the abundance of AOB populations is greater than that of NOB populations. However, urban domestic sewage often does not have the environment to control NOB such as high temperature, high pH value, high FA and FNA inhibition, and can only gradually replace the whole-process nitrification sludge in the mainstream with short-range nitrification sludge by means of side treatment and biological enhancement. mud. Experiments show that it is difficult to stably achieve short-range nitrification by controlling low dissolved oxygen or short sludge age alone. Before the system runs stably, it can be quickly started by means of bioaugmentation to increase the abundance of short-range nitrification and anammox bacteria; after the start-up operation, the AOB and NOB populations can be stably controlled by real-time control of intermittent aeration. The difference in quantity makes AOB always dominant, which will provide a new way for deep denitrification of urban domestic sewage with low energy and high water volume.

The current biological treatment technologies for deep phosphorus removal mainly include enhanced biological phosphorus removal (EBPR) and denitrification phosphorus removal. Enhanced biological phosphorus removal mainly utilizes that phosphorus accumulating bacteria can not only absorb a large amount of phosphate (PO ₄ ^3- ) to synthesize their own nucleic acid and ATP under aerobic conditions, but also can absorb excess phosphorus against the concentration gradient to synthesize energy-storing polyphosphate particles (PO 4 3- ). That is, metachromatic particles) in the body for its endogenous respiration, these bacteria are called phosphorus accumulating bacteria. Phosphorus accumulating bacteria can also release phosphate (PO ₄ ^3- ) in vitro when anaerobic, so it can create anaerobic, anoxic and aerobic environments, so that phosphorus accumulating bacteria can release anaerobic acid in phosphorus-containing polluted (waste) water first. Phosphorus is then sufficiently over-absorbed under aerobic conditions, and then part of the phosphorus is removed from the sewage (waste) water by sludge discharge. However, denitrification phosphorus removal mainly utilizes denitrifying phosphorus accumulating bacteria (DNPAOs) which can use nitrate nitrogen or nitrite nitrogen as electron donors to fully absorb phosphorus in anoxic environment, and then remove part of it from sewage through sludge discharge. phosphorus.

There are also many coupling processes for deep denitrification and phosphorus removal, such as AAO-BAF, AAO-BCO, A ₂ N and other processes. The means of removing nitrogen and phosphorus all solve the competition of sludge age and carbon source between nitrifying bacteria and phosphorus accumulating bacteria, which is beneficial to phosphorus accumulating bacteria. Nitrogen and phosphorus removal. However, the application of the intermittent aeration real-time control method and the screening method described in the present invention in the process of integrated short-range nitrification anammox simultaneous phosphorus removal can utilize intermittent aeration real-time control on the basis of the autotrophic denitrification technology The ecological environment created by the method makes full use of the carbon source in the original urban domestic sewage to achieve high-efficiency and energy-saving deep nitrogen and phosphorus removal.

SUMMARY OF THE INVENTION

The purpose of the patent of the present invention is to propose a real-time control method of intermittent aeration mode with integrated short-range nitrification anammox and phosphorus removal at the same time. The invention utilizes the difference in the decay rate of ammonia oxidizing bacteria and nitrite oxidizing bacteria in the intermittent aeration mode and the difference in the environmental adaptability during the recovery operation process, and adopts the intermittent aeration treatment method for the activated sludge, which rapidly expands the AOB. At the same time, using the anoxic environment created by intermittent aeration, the organic carbon source in the original biological sewage, and the electron donor generated in the short-range nitrification anammox autotrophic denitrification process Deep denitrification and phosphorus removal are achieved. The invention utilizes the means of biological enhancement to start the integrated reactor, and is supplemented by means of intermittent aeration real-time control and sludge age control means, thereby rapidly realizing the deep denitrification and dephosphorization of urban domestic sewage.

A real-time control method for intermittent aeration for simultaneous short-range nitrification anammox and phosphorus removal, the device used comprises a municipal sewage raw water tank (1), an integrated reactor (2), a computer (3), and a programmable process controller (4) ) and the outlet water tank (5).

The urban sewage raw water tank (1) is provided with a raw water tank overflow pipe (1.1) and a raw water tank vent valve (1.2); the urban domestic sewage is connected to the integrated reactor (2) through an inlet pump (1.3); the integrated reactor ( 2) Equipped with air compressor (2.1), aeration solenoid valve (2.2), gas rotameter (2.3), agitator (2.4), pH and DO measuring instrument (2.5), pH and DO probe (2.6), Water outlet valve (2.7), emptying valve (2.8) and sticky sand block aeration head (2.9); the real-time control system is provided with a computer (3), a programmable process controller (4), a signal converter DA conversion interface (4.1) ), signal converter AD conversion interface (4.2), water inlet relay (4.3), stirring relay (4.4), aeration relay (4.5), drainage relay (4.6); The signal AD conversion interface (4.2) is connected with the computer (3) through a cable, and the sensor analog signal is converted into a digital signal and transmitted to the computer (3); The process controller (4) is connected to transmit the digital instructions of the computer (3) to the programmable process controller (4); the stirrer relay (4.4) is connected with the stirrer (2.4); the pH/DO data signal interface ( 2.5) is connected with the computer (3); the water inlet relay (4.3) is connected with the inlet pump (1.3); the aeration relay (4.5) is connected with the aeration head (2.8) of the sticky sand block; the drain relay (4.6) is connected with the The outlet valve (2.7) is connected; the precipitated water is discharged into the outlet water tank (5) through the outlet valve (2.7), which includes the outlet water tank overflow port (5.1) and the outlet water tank vent valve (5.2).

A real-time control method for intermittent aeration for simultaneous short-range nitrification and anammox removal of phosphorus, characterized in that it comprises the following steps:

1) Startup phase:

The integrated reactor (2) inoculates the stably running short-range nitrification sludge in the domestic sewage reactor, and takes the anammox granular sludge from the stably running anammox reactor (UASB) as seed sludge for inoculation , in which the mass ratio of short-range nitrification sludge and anammox granular sludge in the reactor is 4:1, and the total sludge concentration is controlled at 4000-5000 mg/L. The integrated reactor (2) is continuously aerated for 1-3 days with an aeration rate of 1.2-1.5 mg/L after the seed sludge is inoculated.

2) Operation stage:

The integrated reactor (2) is equipped with an air compressor (2.1) for aeration, mixing and stirring with a mechanical stirring paddle (2.4) in the water inlet and reaction stages. The hydraulic retention time of the integrated reactor is 6h, and it runs for 4 cycles per day. At the beginning of each cycle, the feed water pump (1.3) is controlled by the real-time control system to pump the raw domestic sewage into the integrated reactor (2), and the aeration volume is adjusted by the gas rotameter (2.3) to make the integrated reactor dissolve oxygen. The concentration is controlled at 0.8-1.2mg/L. Intermittent aeration is controlled by a real-time control system. Each cycle is 6 hours, including 4 minutes of water inflow, 330 minutes of intermittent aeration, 22 minutes of sedimentation, and 4 minutes of drainage. It runs 4 cycles per day. In the intermittent aeration stage, the real-time control system is used to intermittently adjust the aeration, alternately open or close the air compressor (2.1), and provide 11 cycles of anoxic stirring for 22 minutes and then hypoxic aeration for 8 minutes, and the aeration volume is 0.8-1.2mg /L operating conditions. The effluent of the integrated reactor (2) is drained through the outlet valve (2.7), and the drainage ratio is 50%. The integrated reactor (2) discharges flocculent sludge every cycle, and the flocculation sludge age is 30-50d. The temperature in the integrated reactor (2) is controlled at 30-35°C by heating equipment.

3) Screening and discharging stage:

A 200-micron screen is selected for screening to remove the flocculent sludge, and the retained anammox granular sludge is added to the integrated reactor (2) at the end of each cycle of water inflow.

The patent of the present invention has the following advantages:

(1) The intermittent aeration real-time control method of integrated short-range nitrification and anammox can accurately realize 4 minutes of water inflow, 330 minutes of intermittent aeration, 22 minutes of precipitation, and 4 minutes of water effluent.

(2) The present invention can rapidly enrich ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria in the integrated reactor, so as to realize the rapid start-up of the system and good autotrophic denitrification efficiency. At the same time, it can also quickly realize the rapid accumulation of nitrite, and then use it as a substrate for anammox reaction for autotrophic denitrification. Due to the phosphorus removal in the first few intermittent aeration cycles, the organic components in the raw water are consumed, so the process of autotrophic nitrogen removal can be carried out smoothly. can react normally.

(3) The present invention can create an ecological environment favorable for phosphorus removal through the intermittent aeration real-time control method. The nitrate nitrogen produced by the anammox reaction is used as an electron donor, which can be used to remove phosphorus by denitrifying phosphorus removal bacteria during the anoxic stage, and can also remove 11% of the nitrate nitrogen produced by the anammox reaction. , to achieve deep denitrification. Due to the anaerobic ammonium oxidation reaction and the inhomogeneity of anoxic stirring during the anoxic process, an anaerobic environment suitable for the storage of carbon sources in the phosphorus accumulating bacteria is created; the operation mode of intermittent aeration also gives the phosphorus accumulating bacteria The biological driving force of anaerobic phosphorus release and aerobic phosphorus absorption enables phosphorus accumulating bacteria to efficiently remove phosphorus, and the phosphorus removal rate can reach more than 95%.

(4) Improve sludge sedimentation performance. The fine flocculent sludge rich in phosphate helps to accelerate the settling of the sludge during the sedimentation process and prevent the loss of ammonia oxidizing bacteria and anammox bacteria.

(5) The cost of economic input is low. The method does not need to change the original device and equipment, and does not need to purchase other control instruments, and the main energy consumption sources are aeration and stirring.

The invention is suitable for newly-built or need-upgraded SBR processes, and can rapidly realize the deep denitrification and dephosphorization of urban sewage.

Description of drawings

Fig. 1 is the device structure schematic diagram that the present invention is implemented in the integrated reactor;

In Figure 1, 1 is the urban sewage raw water tank, 1.1 is the overflow pipe of the raw water tank, 1.2 is the vent valve of the raw water tank, 1.3 is the inlet pump; 2 is the integrated reactor, 2.1 is the air compressor, 2.2 is the aeration solenoid valve, 2.3 is the gas rotameter, 2.4 is the stirrer, 2.5 is the pH and DO measuring instrument, 2.6 is the pH and DO probe, 2.7 is the water outlet valve, 2.8 is the emptying valve, 2.9 is the sticky sand block aeration head; 3 is the computer , 4 is the programmable process controller, 4.1 is the DA conversion interface of the signal converter, 4.2 is the AD conversion interface of the signal converter, 4.3 is the water inlet relay, 4.4 is the stirring relay, 4.5 is the aeration relay, and 4.6 is the drainage relay; 5 It is the outlet water tank, 5.1 is the overflow port of the outlet water tank, and 5.2 is the emptying valve of the outlet water tank.

FIG. 2 is a flow chart of a real-time control method for intermittent aeration in a specific embodiment of the present invention.

Detailed ways

The present invention will be described in further detail below with reference to the accompanying drawings and technical solutions, but the present invention is not limited to the following embodiments.

Below in conjunction with concrete example, the method described in the present invention is further introduced:

The domestic sewage in the family area of Beijing University of Technology was used as raw water in the experiment. The specific water quality is as follows: COD concentration is 120-230mg/L, NH ₄ ⁺ -N concentration is 58-87mg/L, NO ₂ ^- -N≤2mg/L, NO ₃ ^- -N≤1.5mg/L. The experimental system is shown in Figure 1. Each reactor is made of plexiglass. The total volume of the integrated reactor is 11L, of which the effective volume is 10L.

The device used includes a raw water tank (1) for urban sewage, an integrated reactor (2), a computer (3), a programmable process controller (4) and a water outlet tank (5).

The urban sewage raw water tank (1) is provided with a raw water tank overflow pipe (1.1) and a raw water tank vent valve (1.2); the urban domestic sewage is connected to the integrated reactor (2) through an inlet pump (1.3); the integrated reactor ( 2) Equipped with air compressor (2.1), aeration solenoid valve (2.2), gas rotameter (2.3), agitator (2.4), pH and DO measuring instrument (2.5), pH and DO probe (2.6), Water outlet valve (2.7), emptying valve (2.8) and sticky sand block aeration head (2.9); the real-time control system is provided with a computer (3), a programmable process controller (4), a signal converter DA conversion interface (4.1) ), signal converter AD conversion interface (4.2), water inlet relay (4.3), stirring relay (4.4), aeration relay (4.5), drainage relay (4.6); The signal AD conversion interface (4.2) is connected with the computer (3) through a cable, and the sensor analog signal is converted into a digital signal and transmitted to the computer (3); The process controller (4) is connected to transmit the digital instructions of the computer (3) to the programmable process controller (4); the stirrer relay (4.4) is connected with the stirrer (2.4); the pH/DO data signal interface ( 2.5) is connected with the computer (3); the water inlet relay (4.3) is connected with the inlet pump (1.3); the aeration relay (4.5) is connected with the aeration head (2.8) of the sticky sand block; the drain relay (4.6) is connected with the The outlet valve (2.7) is connected; the precipitated water is discharged into the outlet water tank (5) through the outlet valve (2.7), which includes the outlet water tank overflow port (5.1) and the outlet water tank vent valve (5.2).

The specific operation is as follows:

1) Startup phase:

The integrated reactor (2) inoculates the stably running short-range nitrification sludge in the domestic sewage reactor, and takes the anammox granular sludge from the stably running anammox reactor (UASB) as seed sludge for inoculation , in which the mass ratio of short-range nitrification sludge and anammox granular sludge in the reactor is 4:1, and the total sludge concentration is controlled at 4000-5000 mg/L. The integrated reactor (2) is continuously aerated for 1-3 days with an aeration rate of 1.2-1.5 mg/L after the seed sludge is inoculated.

2) Operation stage:

The integrated reactor (2) is equipped with an air compressor (2.1) for aeration, mixing and stirring with a mechanical stirring paddle (2.4) in the water inlet and reaction stages. The hydraulic retention time of the integrated reactor is 6h, and it runs for 4 cycles per day. At the beginning of each cycle, the feed water pump (1.3) is controlled by the real-time control system to pump the raw domestic sewage into the integrated reactor (2), and the aeration volume is adjusted by the gas rotameter (2.3) to make the integrated reactor dissolve oxygen. The concentration is controlled at 0.8-1.2mg/L. Intermittent aeration is controlled by a real-time control system. Each cycle is 6 hours, including 4 minutes of water inflow, 330 minutes of intermittent aeration, 22 minutes of sedimentation, and 4 minutes of drainage. It runs 4 cycles per day. In the intermittent aeration stage, the real-time control system is used to intermittently adjust the aeration, alternately open or close the air compressor (2.1), and provide 11 cycles of anoxic stirring for 22 minutes and then hypoxic aeration for 8 minutes, and the aeration volume is 0.8-1.2mg /L operating conditions. The effluent of the integrated reactor (2) is drained through the outlet valve (2.7), and the drainage ratio is 50%. The integrated reactor (2) discharges flocculent sludge every cycle, and the flocculation sludge age is 30-50d. The temperature in the integrated reactor (2) is controlled at 30-35°C by heating equipment.

3) Screening and discharging stage:

A 200-micron screen is selected for screening to remove the flocculent sludge, and the retained anammox granular sludge is added to the integrated reactor (2) at the end of each cycle of water inflow.

Further, after the integrated reactor runs stably, the aeration amount is adjusted in time according to the ammonia nitrogen concentration and total phosphorus content in the effluent to prevent the occurrence of over-aeration.

Claims (2)

1. the intermittent aeration real-time control method of integrated short-range nitrification anammox simultaneously removing phosphorus, it is characterized in that, used device comprises urban sewage raw water tank (1), integrated reactor (2), computer (3), can programming a process controller (4) and a water outlet tank (5); The urban sewage raw water tank (1) is provided with a raw water tank overflow pipe (1.1) and a raw water tank vent valve (1.2); the urban domestic sewage is connected to the integrated reactor (2) through an inlet pump (1.3); the integrated reactor ( 2) Equipped with air compressor (2.1), aeration solenoid valve (2.2), gas rotameter (2.3), agitator (2.4), pH and DO measuring instrument (2.5), pH and DO probe (2.6), Water outlet valve (2.7), emptying valve (2.8) and sticky sand block aeration head (2.9); the real-time control system is provided with a computer (3), a programmable process controller (4), a signal converter DA conversion interface (4.1) ), signal converter AD conversion interface (4.2), water inlet relay (4.3), stirring relay (4.4), aeration relay (4.5), drainage relay (4.6); The signal AD conversion interface (4.2) is connected with the computer (3) through a cable, and the sensor analog signal is converted into a digital signal and transmitted to the computer (3); The process controller (4) is connected to transmit the digital instructions of the computer (3) to the programmable process controller (4); the stirrer relay (4.4) is connected with the stirrer (2.4); the pH/DO data signal interface ( 2.5) is connected with the computer (3); the water inlet relay (4.3) is connected with the inlet pump (1.3); the aeration relay (4.5) is connected with the aeration head (2.8) of the sticky sand block; the drain relay (4.6) is connected with the The outlet valve (2.7) is connected; the precipitated water is discharged into the outlet water tank (5) through the outlet valve (2.7), which includes the outlet water tank overflow port (5.1) and the outlet water tank vent valve (5.2); Include the following steps: 1) Startup phase: The integrated reactor (2) inoculates the stably running short-range nitrification sludge in the domestic sewage reactor, and takes the anammox granular sludge from the stably running anammox reactor as seed sludge for inoculation, wherein the reaction The mass ratio of short-distance nitrification sludge and anammox granular sludge in the reactor is 4:1, and the total sludge concentration is controlled at 4000-5000mg/L; the integrated reactor (2) is inoculated with 1.2-1.5mg of seed sludge The aeration volume of /L is continuously aerated for 1-3 days; 2) Operation stage: The integrated reactor (2) is equipped with an air compressor (2.1) for aeration, and the mechanical stirring paddle (2.4) is used for mixing and stirring during the water inlet and reaction stages; the hydraulic retention time of the integrated reactor is 6h, and 4 are operated every day. cycle; at the beginning of each cycle, the feed pump (1.3) is controlled by the real-time control system to pump the raw domestic sewage into the integrated reactor (2), and the aeration volume is adjusted by the gas rotameter (2.3) to make the integrated reactor (2.3). Dissolved oxygen concentration is controlled at 0.8-1.2mg/L; intermittent aeration is controlled by a real-time control system, each cycle is 6h, including 4min water inflow, 330min intermittent aeration, 22min sedimentation, 4min drainage, running 4 cycles per day; In the aeration stage, the real-time control system is used to intermittently adjust the aeration, alternately open or close the air compressor (2.1), and provide 11 cycles of anoxic stirring for 22 minutes and then hypoxic aeration for 8 minutes. The aeration rate is 0.8-1.2mg/L. Operating conditions; the effluent of the integrated reactor (2) is drained through the outlet valve (2.7), and the drainage ratio is 50%; the integrated reactor (2) discharges flocculent sludge every cycle, and the floc sludge age is 30-50d ; The temperature in the integrated reactor (2) is controlled at 30-35°C by heating equipment. 2. The method according to claim 1, characterized in that, after the step 2), it also comprises: selecting a 200-micron screen for screening, sieving out the flocculent sludge, and trapping the retained anaerobic ammonium oxidation particulate sludge. Sludge is added to the integrated reactor (2) at the end of the water feed stage of each cycle.

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