CN112573647B

CN112573647B - Method for culturing aerobic granular sludge for synchronous short-cut nitrification and denitrification of degraded pyridine

Info

Publication number: CN112573647B
Application number: CN202011592513.8A
Authority: CN
Inventors: 吴施婧; 梁培瑜; 邓觅; 吴永明; 朱林; 李荣富; 涂文清
Original assignee: INSTITUTE OF MICROBIOLOGY JIANGXI ACADEMY OF SCIENCES
Current assignee: INSTITUTE OF MICROBIOLOGY JIANGXI ACADEMY OF SCIENCES
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2021-07-20
Anticipated expiration: 2040-12-29
Also published as: CN112573647A

Abstract

The invention relates to a biological sewage treatment technology in the field of environmental protection, in particular to a method for quickly culturing and degrading pyridine synchronous shortcut nitrification denitrification aerobic granular sludge. The invention realizes synchronous short-cut nitrification and denitrification by controlling reaction parameters, and solves the problems of long treatment flow, large equipment floor area, high energy consumption and the like in the traditional biological denitrification process; the problems of long granulation time, instability of granular sludge, low denitrification efficiency and the like of aerobic granular sludge are solved by biologically and intensively adding denitrifying granular sludge, monitoring and controlling DO concentration in a regulation and control system in real time, mutual cooperation of heterotrophic bacteria, nitrosobacteria and denitrifying bacteria is finally realized, the quality of outlet water is regulated and controlled by regulating the concentration of inlet ammonia nitrogen, HRT and the like, the inlet water condition of a subsequent anaerobic ammonia oxidation process is met, complete mineralization treatment of nitrogen heterocyclic ring organic matters such as pyridine and the like is realized, and the biological treatment method has important guiding significance for biological treatment of difficultly degraded toxic and harmful pollutants.

Description

Method for culturing aerobic granular sludge for synchronous short-cut nitrification and denitrification of degraded pyridine

Technical Field

The invention relates to the technical field of biological sewage treatment in the field of environmental protection, in particular to a method for quickly constructing a nitrogen heterocyclic ring degradation-resistant organic compound biodegradation and synchronous short-cut nitrification and denitrification aerobic granular sludge system.

Background

The nitrogenous heterocyclic compounds such as pyridine and the like widely exist in industrial wastewater such as printing and dyeing wastewater, coking wastewater and the like, are important chemical raw materials, have the characteristics of teratogenesis, carcinogenesis, mutagenesis and the like, and have poor biodegradability, and the traditional physical and chemical method has overhigh treatment cost and poor traditional biological treatment technical effect. How to economically and efficiently treat the chemical wastewater becomes one of the important problems to be solved urgently in the field of water treatment.

The aerobic granular sludge is a granular microorganism aggregate formed by self-immobilization, has good activity and sedimentation performance, rich microbial community and low sludge yield, can well resist the impact of toxic and harmful substances and hydraulic load, and has certain effect on the biodegradation of toxic and harmful chemical wastewater by utilizing the aerobic granular sludge at present. In addition, nitrogen can be converted into ammonia nitrogen during ring opening of the nitrogenous heterocyclic compound, water eutrophication is easily caused if the nitrogenous heterocyclic compound is not further treated, DO diffusion is limited due to the special film structure of the aerobic granular sludge, and an aerobic zone, an anoxic zone and an anaerobic zone are sequentially formed from outside to inside, so that nitrification and denitrification of microorganisms with different functions can be simultaneously realized in the same system, the cost of a secondary sedimentation tank and sludge backflow can be saved, and the treatment cost is saved.

The traditional biological denitrification process is that ammonia undergoes complete nitration and is converted into NO₃ ^-After N, denitrification is carried out to convert the nitrogen into gaseous nitrogen, the NOB activity is inhibited by utilizing the characteristics that the affinity of AOB to DO (the DO half-saturation coefficient is 0.3 mg/L) is greater than that of NOB (the DO half-saturation coefficient is 1.1 mg/L), the tolerance concentration of AOB to FA (10-150 mg/L) is greater than that of NOB (0.1-1 mg/L) and the like in the short-cut nitrification process, so that the nitrification process is controlled to be NO₂ ^--N stage, NO longer continuing conversion to NO₃ ^--N. The short-cut nitrification can save 25 percent of oxygen supply in the nitrification stage and 40 percent of carbon source supply in the denitrification stage, and the process has low sludge yield, the sludge yield of the short-cut nitrification and the subsequent denitrification can be respectively reduced by 35 percent and 55 percent compared with the traditional biological denitrification, and simultaneously, the reaction time can be shortened, the volume of a reactor can be reduced, and the investment and operation cost can be reduced. The novel denitrification process combining partial nitrification and anaerobic ammonia oxidation is the most economic biological denitrification process so far, and the anaerobic ammonia oxidation process utilizes NH₄ ⁺As electron donors, NO₂ ^-the-N is used as an electron acceptor and is converted into nitrogen to be removed, no additional carbon source is needed to be added, the application prospect is wide, and the treatment of performing short-cut nitrification denitrification and combining anaerobic ammonia oxidation on the pyridine wastewater by using the aerobic granular sludge system has obvious economic benefit.

Although the aerobic granular sludge has good impact load resistance, toxic and harmful wastewater resistance and capability of simultaneously removing organic carbon and denitrifying, some short plates still exist in practical application, particularly when the wastewater difficult to biodegrade is used as a substrate, the culture of the aerobic granular sludge generally needs more than 3 months, the denitrifying capability is weak, and the sludge disintegration phenomenon is easy to occur after long-term operation, so that the current academic research is a lot and the practical application is less.

Disclosure of Invention

The invention provides a method for quickly starting and stably operating denitrification aerobic granular sludge suitable for toxic and harmful chemical wastewater such as pyridine and the like, aiming at the problems of longer granulation time, lower denitrification efficiency and the like in the process of synchronously denitrifying organic wastewater by using aerobic granular sludge at present, and the like, so that the denitrification efficiency of a system can be effectively improved, and the resource utilization maximization is realized. The specific technical scheme is as follows:

the method comprises the following steps:

(1) inoculating specific pyridine degrading bacteria Rhizobium sp.NJUST18 into an inorganic salt liquid culture medium with pyridine as a unique carbon source, performing constant-temperature culture by using a shaking table, centrifuging the bacterial liquid and collecting bacterial centrifuges for later use after a large amount of hyphae are obviously seen, wherein the Rhizobium sp.NJUST18 is preserved in a China typical culture preservation center CCTCC at 28 th 3 and 28 th 2013, the preservation unit address is Wuhan university in Wuhan city, Hubei province, China, and the preservation number is CCTCC NO: M2013110, namely Rhizobium NJUST18, the classification name is Rhizobium sp.and the GenBank login number is JN 106368;

(2) taking the dewatered mud cake as inoculated sludge, putting into an SBR reactor, continuously aerating for 24-30h, and recovering the microbial activity in the sludge;

(3) directly adding the bacterial centrifuges enriched and cultured in the step (1) into the SBR reactor after hollow aeration in the step (2), introducing artificial simulated wastewater with sodium acetate and pyridine as carbon sources for running culture, and gradually reducing the concentration of the sodium acetate and increasing the concentration of the pyridine in the running process until water enters and pyridine is used as a unique carbon source to enrich nitrobacteria;

(4) taking one third of sludge in the SBR reactor after the stable operation of the step (3), and culturing the denitrification granular sludge under the condition of low dissolved oxygen; adopting the discharged liquid after the reaction in the step (3) as a culture solution, adjusting the pH, adding pyridine as a denitrification electron donor, and simultaneously adding CaO for sequencing batch culture to form denitrification granular sludge;

(5) and (3) inoculating the denitrification granular sludge obtained by culturing in the step (4) into the SBR reactor enriched with nitrobacteria obtained in the step (3), gradually forming aerobic granular sludge in a mode of high hydraulic shearing and gradually reducing sedimentation time in the operation process, properly reducing aeration amount and improving the concentration of ammonia nitrogen in inlet water, realizing stable shortcut nitrification, and obtaining the shortcut nitrification denitrification granular sludge capable of degrading pyridine.

Further, in the step (1), 500mg/L of pyridine was added to the inorganic salt liquid medium.

Further, the mud cakes in the step (2) are dewatered by chemical sewage treatment plants such as printing and dyeing wastewater, coking wastewater and the like, and the water content is 75-80%. The sludge structure is firm and compact, a 'crystal nucleus' can be provided for the initial granulation of the sludge, microorganisms in a sludge cake after the air aeration are in a hungry state, the microorganisms with low viability are eliminated, the remained microorganisms continuously adapt to a new environment and tend to agglomerate and grow, and the formation of aerobic granular sludge in the system can be promoted.

Further, the artificial simulation wastewater is as follows: 80mg/L of calcium chloride, 15mg/L of ferrous chloride, 250mg/L of magnesium sulfate heptahydrate and 65mg/L of potassium chloride, and the pH is controlled to be 7-7.5 by the buffer solution of potassium dihydrogen phosphate and disodium hydrogen phosphate dodecahydrate.

Further, the specific operation process of the step (3) is as follows: 1000mg/L sodium acetate and 500mg/L pyridine are added into the simulated wastewater, a reactor runs according to the sequence period of water inlet, aeration, precipitation and drainage, the initial reaction period is set to be 12-16h, wherein the settling time is 12min, the surface gas velocity is controlled to be 2cm/s, the concentration of sodium acetate is reduced by 200mg/L and the concentration of pyridine is increased by 200mg/L every 2 to 3 days in the operation process until the water enters the reactor and the 1500mg/L of pyridine is used as a unique carbon source, adopts a mode of alternately operating high aeration quantity and low aeration quantity, the high aeration quantity and the low aeration quantity are respectively 200L/h and 60L/h, the corresponding surface gas velocity is 2cm/s and 0.6cm/s, the dissolved oxygen concentration is between 1mg/L and 7mg/L, and when the sludge concentration in the system is obviously increased, the start-up stage of the reactor is ended.

Further, the sequencing batch culture of the step (4) specifically comprises: 24h is a culture period, feeding is carried out once, the stirrer is used for stirring, the stirring speed is controlled at 180r/min, the anoxic environment is ensured, stirring is carried out for 23h in the culture period, sedimentation is carried out for 30min, and then water is discharged and fed; when the total nitrogen removal rate in the system reaches 8-10mg/L/h and the average particle size of the granular sludge reaches 0.5-0.6mm, the denitrification granular sludge is considered to be mature in culture; wherein the addition amount of CaO is 5-10mg/L, the concentration of pyridine is 500mg/L, and the pH can be adjusted to 7-7.5 by phosphate buffer solution. CaO is added during the cultivation of the denitrifying granular sludge, which forms Ca (OH) under alkaline conditions₂With CO produced by microbial metabolism₂The reaction may form fine CaCO₃The calcium carbonate can be used as a nucleus for inducing sludge granulation, so that microorganisms can be rapidly aggregated around the nucleus, and the granulation of the denitrification sludge is accelerated.

Further, in the step (5), the fed water is controlled to use pyridine as a unique carbon source, the operation period is set to be 12 hours, the concentration is 1500mg/L, the surface gas velocity is 2cm/s, and the dissolved oxygen is 7mg/L at the initial operation stage. And gradually reducing the sedimentation time in the operation process, wherein the sedimentation time of 1-4 days is 12min, the sedimentation time of 5-8 days is 9min, the sedimentation time of 9-12 days is 6min, and the sedimentation time of 13-16 days is 3min, the pyridine degradation starvation period is controlled to be 2-3h in each operation period, when the pyridine running to 1500mg/L can be degraded by more than 90% in 6h, the operation period of the control system is adjusted to be 8h, the aeration amount is reduced to 100L/h, the corresponding surface air velocity is 1cm/s, the dissolved oxygen of 5mg/L in the initial operation period is added into the simulated wastewater, and 250mg/L of ammonium chloride is added into the simulated wastewater to stably culture the short-range nitrification denitrification granular sludge capable of degrading the pyridine.

Culturing denitrified aerobic granular sludge capable of efficiently degrading pyridine by means of high hydraulic shearing and gradually reducing settling time. Under the action of the cross winding of hydraulic shearing force, the denitrifying granular sludge becomes a new core, the pyridine degrading bacteria and the nitrifying bacteria are gradually wrapped outside the original denitrifying granular sludge, the settling time is gradually reduced, microorganisms with weak settling capacity are eliminated, and the microorganisms with good settling performance are retained in the reactor. In the operation process, the operation period of the reactor is gradually adjusted to be reduced from 12h to 8h according to the pyridine period degradation condition, the appropriate starvation period is controlled, the microorganisms are promoted to secrete extracellular polymers, and the polysaccharide, the protein and other substances can improve the stability of the granular sludge. After the aerobic granular sludge is formed, the aeration rate is properly reduced, the ammonia nitrogen concentration of inlet water is improved, the activity of NOB is inhibited, and finally, stable short-cut nitrification is realized.

Furthermore, for the short-cut nitrification denitrification granular sludge for culturing the degradable pyridine, a method of alternately operating high and low dissolved oxygen is adopted, so that the denitrification efficiency is improved.

Further, the adopted culture device comprises an SBR reactor, a water inlet system, a drainage system, an aeration system, a DO online monitor and a PLC control system; the SBR reactor is a cylindrical double-layer organic glass cylinder with the height-diameter ratio of 15-18, circulating water can be introduced into the outer layer for water bath heat preservation, a plurality of valves for water inlet, air inlet, water discharge, sampling and sludge discharge are arranged on the inner layer, and an exhaust port is positioned right above the SBR reactor; the water inlet system comprises a water inlet barrel, a water inlet pipe and a peristaltic pump, and the water inlet is arranged at the bottom of the reactor; the water outlet is positioned in the middle of the reactor, ensures that the volume exchange ratio of water is 50% each time, is connected with a normally closed electromagnetic valve and is controlled by an automatic controller; the aeration system comprises an air compressor, a gas flowmeter and a cylindrical microporous aeration head, wherein the aeration head and an air inlet are positioned at the bottom of the reactor; one end of the DO on-line monitor is directly inserted into the reactor main body, and the other end is connected with the PLC controller.

In the invention, a synergistic effect exists between the pyridine degradation and the denitrification, and a competitive relationship exists between the pyridine degradation and the denitrification. In the earlier stage of a sequencing batch reaction, a large amount of dissolved oxygen is consumed by degrading pyridine, because the adsorption capacity of nitrifying bacteria on DO is smaller than that of heterotrophic bacteria, the nitrifying bacteria cannot obtain sufficient DO, the DO in the system is maintained at a lower level, and the dissolved oxygen entering the granular sludge through diffusion is reduced, so that anoxic and anaerobic denitrifying bacteria can realize denitrifying denitrification in the aerobic granular sludge; in the later stage of the reaction, pyridine is almost completely degraded, nitrifying bacteria obtain enough DO, ammonia nitrogen generated by the degradation of the pyridine in the earlier stage can be converted into nitrite nitrogen, and an electron acceptor is provided for the denitrification process of the next period.

According to the invention, the DO concentration in the system is monitored in real time by arranging the DO probe, the reaction process can be known more visually, linkage is formed by connecting the PLC automatic control system and the aeration device, and after the DO passes through the DO low point, the aeration quantity of the system is reduced by the automatic control system, so that the supply of power for the operation of the reactor can be reduced, the utilization rate of oxygen is improved, good reaction conditions can be provided for denitrifying bacteria in granular sludge, the denitrification efficiency is improved, and the device has an important effect in practical application. In the process, a large amount of dissolved oxygen is consumed by the pyridine degrading bacteria at the initial stage of reaction, the DO concentration is gradually reduced, after the pyridine is basically completely degraded, the demand of the nitrosobacteria on the dissolved oxygen is small, and the DO concentration in the system is obviously increased after an inflection point appears.

The invention uses partial sludge in the system to culture the denitrifying granular sludge in an enhanced way and adds the denitrifying granular sludge back to the original SBR system, and the denitrifying granular sludge is used as the core of the aerobic granular sludge, thereby optimizing the granular sludge structure, accelerating the granulation process and improving the denitrifying bacteria ratio and the denitrification efficiency. The denitrifying granular sludge is not added, and the aerobic granular sludge in the system constructed by the single pyridine degrading bacteria is in a faint yellow spherical shape, the surface is smooth, the outer contour is clear, and the average grain size is about 1 mm. The granular sludge is yellow elliptic or spherical, the particle size is obviously increased, the average particle size can reach more than 2mm, the surface of the sludge is porous and has higher specific surface area, the mass transfer of Dissolved Oxygen (DO) and nutrient substances can be guaranteed, and the denitrification efficiency can reach more than 50 percent at most.

According to the invention, the granular sludge is allowed to have a substrate starvation period, namely a starvation period, of 2-3 hours by controlling the operation period, the period simulates that pyridine, a carbon source in wastewater is degraded and exhausted, the carbon source provided by the outside cannot meet the growth requirement of microorganisms, and the microorganisms utilize nutrients stored by the microorganisms, degradation intermediate products, intracellular and extracellular polymers to perform endogenous respiration. The microorganisms can be stimulated to secrete EPS in a proper hunger period to cope with the hunger state, and polysaccharide and protein substances in the EPS can increase the hydrophobicity of the cell surface, enhance the affinity among cells, improve the agglomeration capacity among the microorganisms and be beneficial to the long-term stable operation of an aerobic particle system. If the starvation period does not exist, the residual pyridine in the previous period can be continuously accumulated to the next period, the pyridine load is overhigh, and if the starvation period is overlong, the nutrient substance is lack, so that the microorganism proliferation is not facilitated, and finally, the zoogloea is decomposed, and the sedimentation performance is deteriorated.

According to the invention, by utilizing the difference of the oxygen saturation coefficients, the optimal growth temperature and the tolerance degree to FA of AOB and NOB, the DO and FA concentrations and the temperature in the system are suitable for the growth of AOB by controlling parameters such as aeration quantity, pH, water temperature, influent ammonia nitrogen concentration and the like, the activity of NOB is inhibited, the AOB enrichment effect is achieved, and the nitrite accumulation rate is more than 94%.

The invention provides an economic and efficient biological treatment method for refractory toxic and harmful wastewater of chemical enterprises, realizes synchronous shortcut nitrification and denitrification by controlling reaction parameters, and solves the problems of long treatment flow, large equipment floor area, high energy consumption and the like in the traditional biological denitrification process; the problems of long granulation time, instability of granular sludge, low denitrification efficiency and the like of aerobic granular sludge are solved by biologically and intensively adding denitrifying granular sludge, monitoring and controlling DO concentration in a regulation and control system in real time, mutual cooperation of heterotrophic bacteria, nitrosobacteria and denitrifying bacteria is finally realized, the quality of outlet water is regulated and controlled by adjusting the concentration of inlet ammonia nitrogen, HRT and the like, the inlet water condition of a subsequent anaerobic ammonia oxidation process can be met, complete mineralization treatment of nitrogen heterocyclic ring organic matters such as pyridine and the like is realized, and the biological treatment method has important guiding significance for biological treatment of difficultly degraded toxic and harmful pollutants.

Generally, before biological treatment, the organic wastewater difficult to degrade needs physical-chemical pretreatment, and the invention constructs an aerobic granular sludge system by adding special bacteria for degrading pyridine and directly treats the wastewater by a biological method, thereby saving the pretreatment step and having obvious economic benefit in practical application.

According to the invention, the denitrification granular sludge is biologically and intensively added, the proportion of denitrifying bacteria in the granular sludge is increased, a core is provided for the formation of aerobic granular sludge, the sludge granulation is accelerated, an aerobic granular sludge system is successfully constructed within 2 months, and an automatic high-low dissolved oxygen regulation and control system is constructed by controlling a proper starvation period, so that the operation cost is saved, the denitrification efficiency is improved, the average particle size of the granular sludge is more than 2mm, the denitrification efficiency of the sludge is more than 50%, and the long-term stable operation of the granular sludge is realized.

Compared with the traditional biological denitrification, the invention constructs a synchronous short-cut nitrification and denitrification system, saves 25 percent of oxygen supply and 35 percent of sludge yield in the nitrification stage, saves 40 percent of carbon source supply and 55 percent of sludge yield in the denitrification stage, and nitrosobacteria and denitrifying bacteria exist in the same system, mutually provide substrates in a diffusion mode, eliminate the inhibition caused by the accumulation of respective metabolites, balance the pH, do not need to carry out nitrification liquid reflux, simplify a reaction device, reduce the investment and operation cost, and provide proper water inlet for the subsequent anaerobic ammonia oxidation treatment.

Drawings

FIG. 1 is a graph showing the change of the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and pyridine nitrogen in example 1;

FIG. 2 is a graph showing the change in total nitrogen and DO concentrations in example 1;

FIG. 3 is a graph showing the change in the concentration of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and pyridine nitrogen in example 2;

FIG. 4 is a graph showing the change in the total nitrogen and DO concentrations in example 2;

FIG. 5 is a digital camera of aerobic granular sludge in a system constructed by a single pyridine-degrading bacterium;

FIG. 6 is a microscopic view of aerobic granular sludge in a system constructed by a single pyridine-degrading bacterium;

FIG. 7 is a digital camera of aerobic granular sludge in the system according to example 2 of the present invention;

FIG. 8 is a microscopic image of aerobic granular sludge in the system of example 2 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following examples, 80mg/L of calcium chloride, 15mg/L of ferrous chloride, 250mg/L of magnesium sulfate heptahydrate and 65mg/L of potassium chloride were added to the simulated wastewater. The pH of the feed water was controlled to 7.5 by potassium dihydrogen phosphate and disodium hydrogen phosphate dodecahydrate buffer solution, wherein KH is₂PO₄Is 0.05g/L, Na₂HPO₄▪12H₂O is 1.3g/L, and the temperature of a water bath control system is 30 ℃. Because of the limited laboratory conditions, the DO concentration in the system is measured by a portable DO monitor.

Example 1:

1. inoculating specific bacteria for degrading pyridine, Rhizobium sp.NJUST18, into an inorganic salt culture medium added with 500mg/L pyridine, culturing by using a shaking table, after a large amount of hyphae can be obviously seen, centrifuging the bacterial liquid and collecting a bacterial centrifugal substance for later use.

2. Taking a mud cake obtained after dehydration treatment in a chemical sewage treatment plant as inoculated sludge, wherein the water content of the mud cake is 75-80%, and continuously aerating for 24-30 h.

3. Adding about 3g of special-effect bacteria thallus centrifugate for degrading pyridine into an SBR system directly, pumping simulated wastewater containing 1000mg/L sodium acetate and 500mg/L pyridine into the system through a peristaltic pump, periodically operating a reactor according to the sequence of water inlet, aeration, precipitation and drainage, setting an initial reaction period to be 12h, wherein the settling time is 12min, the surface gas velocity is controlled to be 2cm/s, reducing the concentration of 200mg/L sodium acetate and increasing the concentration of 200mg/L pyridine every 3 days in the operation process until 1500mg/L pyridine is taken as a unique carbon source, adopting a mode of alternately operating with high and low aeration rates, setting the high and low aeration rates to be 200L/h and 60L/h, and setting the corresponding surface gas velocities to be 2cm/s and 0.6 cm/s. When the sludge concentration in the system is obviously increased, the starting stage of the reactor is ended.

4. One third of the sludge was taken out of the system, and the denitrification granular sludge culture was performed under the low dissolved oxygen condition with DO <1.0mg/L, using the system effluent as the culture solution, adjusting pH to 7.5, adding pyridine as the denitrification electron donor, and adding CaO at 8 mg/L. Batch culture is adopted, 24 hours is a culture period, one-time feeding is carried out, a stirrer is used for stirring, the stirring speed is controlled at 120r/min, stirring is carried out for 23 hours in one culture period, sedimentation is carried out for 30min, and then water drainage and water inflow are carried out. When the total nitrogen removal rate in the system reaches 8mg/L/h and the average particle size of the granular sludge reaches about 0.5mm, the culture of the denitrification granular sludge is considered to be mature.

5. And (3) inoculating the denitrification granular sludge into the original SBR reactor again, controlling the water inlet to use pyridine as a unique carbon source, wherein the concentration is 1500mg/L, and the surface gas velocity is 2 cm/s. The sedimentation time is gradually reduced in the operation process, wherein the sedimentation time is 12min on the 1 st to 4 th days, 9min on the 5 th to 8 th days, 6min on the 9 th to 12 th days and 3min on the 13 th to 16 th days. In the operation process, the operation period of SBR is adjusted to be 12h according to the degradation condition of pyridine, the starvation period of 2-3h is controlled, after 20d of stable operation, 1500mg/L of pyridine can be degraded by more than 90% in 6h, and obvious nitration reaction occurs, thus primarily forming mature aerobic granular sludge with pyridine degradation capability and complete nitration capability.

6. The operation period of the control system is 8 hours, the aeration quantity is reduced to 100L/h, the corresponding surface air speed is 1cm/s, 250mg/L of ammonium chloride is added into the simulated wastewater, and the nitrosation denitrification granular sludge is successfully cultured through stable operation for 15 days, so that the stable shortcut nitrification is realized, the nitrite accumulation rate reaches about 94 percent, and the total nitrogen removal rate is 40 to 45 percent. The concentration changes of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and pyridine nitrogen in one operation period are shown in figure 1, and the total nitrogen and DO concentration changes are shown in figure 2.

The concentration of FA during this process was calculated according to the following formula (pH value calculated as 7.5):

concentration of free ammonia (mg/L) =

Under the condition, the concentration of FA in the system is always greater than 3mg/L and the highest concentration is not greater than 10mg/L in a period, NOB activity is obviously inhibited, AOB activity is not inhibited, AOB has higher affinity to oxygen compared with NOB, and the NOB cannot obtain enough oxygen under the condition of reducing aeration quantity, so that the system is finally eliminated.

Example 2:

according to the change situation of DO in FIG. 2, the pyridine removal rate reaches 70% after 4h, the demand of pyridine degrading bacteria on oxygen is reduced, the demand of AOB on oxygen is smaller, the DO concentration is in a gradually rising trend, and the increase of the DO concentration in the system wastes energy consumption and inhibits the activity of denitrifying bacteria in granular sludge. In the experiment, after nitrosation denitrification granular sludge is obtained according to the steps of the application example 1, the aeration amount is adjusted to 30L/h in the 5 th hour of an operation period, the corresponding surface air speed is 0.3cm/s, so that the granular sludge is just in a suspension state in a reactor, the granular sludge is ensured to be fully contacted with wastewater, the pyridine is almost completely degraded, and the oxygen requirement of aerobic pyridine degrading bacteria for degrading residual pyridine is met under the condition of low dissolved oxygen. Meanwhile, the anoxic area inside the granular sludge is increased, denitrifying bacteria inside the granular sludge can utilize PHB, pyridine degradation intermediate products, intracellular and extracellular polymers and the like as carbon sources to carry out denitrifying denitrification, so that the later-stage power process of system operation can be reduced, the operation cost is reduced, the economic benefit is improved, good reaction conditions can be improved for the denitrifying bacteria, the denitrification efficiency is improved, the total nitrogen removal rate of the system is increased to more than 50%, and the nitrite nitrogen accumulation rate is increased to more than 95%. The concentration changes of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and pyridine nitrogen in one operation period are shown in figure 3, and the total nitrogen and DO concentration changes are shown in figure 4.

Successfully eliminates NOB, optimizes reaction conditions by reducing the ammonia nitrogen concentration of inlet water or increasing aeration time and the like after realizing short-cut nitrification denitrification, ensures that the molar ratio of outlet nitrite nitrogen to ammonia nitrogen is 0.9-1.2, and can provide proper inlet water for subsequent anaerobic ammonia oxidation.

As shown in figures 5 and 6, the aerobic granular sludge in the system constructed by the single pyridine degrading bacteria is in a faint yellow spherical shape, has uniform particle size distribution, has an average particle size not more than 1mm, and has a smooth surface and a clear outer contour without adding the denitrification granular sludge. The invention adds the denitrification granular sludge as the core for culturing the aerobic granular sludge, the aerobic granular sludge is in a yellow elliptical shape or a spherical shape as shown in figures 7 and 8, the grain diameter is obviously increased and is different from 1mm to 4mm, and the average grain diameter can reach more than 2 mm.

Although the preferred embodiments of the present patent have been described in detail, the present patent is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present patent within the knowledge of those skilled in the art.

Claims

1. A method for rapidly culturing and degrading pyridine synchronous short-cut nitrification denitrification aerobic granular sludge is characterized by comprising the following steps: the method comprises the following steps:

(1) inoculating specific bacteria for degrading pyridine, Rhizobium sp.NJUST18, into an inorganic salt liquid culture medium with pyridine as a unique carbon source, performing constant-temperature culture by using a shaking table, centrifuging a bacterial liquid and collecting a bacterial centrifugal substance for later use after a large amount of hypha is obviously seen;

(5) inoculating the denitrifying granular sludge obtained by culturing in the step (4) into the SBR reactor enriched with nitrifying bacteria obtained in the step (3), gradually forming aerobic granular sludge in a mode of high hydraulic shearing and gradually reducing sedimentation time in the operation process, properly reducing aeration amount and improving the concentration of ammonia nitrogen in inlet water, realizing stable short-cut nitrification, and obtaining the short-cut denitrifying granular sludge capable of degrading pyridine; controlling the inflow water to use pyridine as a unique carbon source, setting the operation period to be 12h, setting the concentration to be 1500mg/L, setting the surface gas velocity to be 2cm/s, and setting the dissolved oxygen to be 7mg/L at the initial operation stage; gradually reducing the sedimentation time in the operation process, wherein the sedimentation time of 1-4 days is 12min, the sedimentation time of 5-8 days is 9min, the sedimentation time of 9-12 days is 6min and the sedimentation time of 13-16 days is 3min, and the starvation period for pyridine degradation in each operation period is controlled to be 2-3 h; when the pyridine which runs to 1500mg/L can be degraded by more than 90 percent in 6 hours, adjusting the running period of the control system to 8 hours, reducing the aeration amount to 100L/h, controlling the corresponding surface air speed to be 1cm/s, controlling the dissolved oxygen to be 5mg/L at the initial running stage, adding 250mg/L of ammonium chloride into the simulated wastewater, and stably culturing the short-cut nitrification denitrification granular sludge capable of degrading the pyridine;

(6) for the short-cut nitrification denitrification granular sludge for culturing the degradable pyridine, a method of alternately operating high and low dissolved oxygen is adopted, so that the denitrification efficiency is improved;

the Rhizobium sp.NJUST18 is preserved in a China typical culture preservation center CCTCC at 28 th 2013, the preservation unit address is Wuhan university in Wuhan City, Hubei province, China, the preservation number is CCTCC NO: M2013110, the name is Rhizobium NJUST18, the classification name is Rhizobium sp.and the GenBank login number is JN 106368.

2. The method for rapidly culturing and degrading pyridine synchronous shortcut nitrification and denitrification aerobic granular sludge according to claim 1, wherein the method comprises the following steps: adding 500mg/L pyridine into the inorganic salt liquid culture medium in the step (1).

3. The method for rapidly culturing and degrading pyridine synchronous shortcut nitrification and denitrification aerobic granular sludge according to claim 1, wherein the method comprises the following steps: and (3) in the step (2), the mud cake is dehydrated by a chemical sewage treatment plant, and the water content is 75-80%.

4. The method for rapidly culturing and degrading pyridine synchronous shortcut nitrification and denitrification aerobic granular sludge according to claim 1, wherein the method comprises the following steps: the artificial simulated wastewater contains 80mg/L of calcium chloride, 15mg/L of ferrous chloride, 250mg/L of magnesium sulfate heptahydrate and 65mg/L of potassium chloride, and the pH is controlled to be 7-7.5 by the buffer solution of potassium dihydrogen phosphate and disodium hydrogen phosphate dodecahydrate.

5. The method for rapidly culturing and degrading pyridine synchronous shortcut nitrification and denitrification aerobic granular sludge according to claim 1, wherein the method comprises the following steps: the specific operation process of the step (3) is as follows: adding 1000mg/L sodium acetate and 500mg/L pyridine into the artificial simulated wastewater, periodically operating the reactor according to the sequence of water inlet, aeration, precipitation and drainage, setting the initial reaction period to be 12-16h, wherein the settling time is 12min, the surface gas velocity is controlled to be 2cm/s, the concentration of sodium acetate is reduced by 200mg/L and the concentration of pyridine is increased by 200mg/L every 2 to 3 days in the operation process until the water enters the reactor and the 1500mg/L of pyridine is used as a unique carbon source, adopts a mode of alternately operating high aeration quantity and low aeration quantity, the high aeration quantity and the low aeration quantity are respectively 200L/h and 60L/h, the corresponding surface gas velocity is 2cm/s and 0.6cm/s, the dissolved oxygen concentration is between 1mg/L and 7mg/L, and when the sludge concentration in the system is obviously increased, the start-up stage of the reactor is ended.

6. The method for rapidly culturing and degrading pyridine synchronous shortcut nitrification and denitrification aerobic granular sludge according to claim 1, wherein the method comprises the following steps: the sequencing batch culture in the step (4) comprises the following specific steps: 24h is a culture period, feeding is carried out once, the stirrer is used for stirring, the stirring speed is controlled at 180r/min, the anoxic environment is ensured, stirring is carried out for 23h in the culture period, sedimentation is carried out for 30min, and then water is discharged and fed; when the total nitrogen removal rate in the system reaches 8-10mg/L/h and the average particle size of the granular sludge reaches 0.5-0.6mm, the denitrification granular sludge is considered to be mature in culture; wherein the addition amount of CaO is 5-10mg/L, the concentration of pyridine is 500mg/L, and the pH can be adjusted to 7-7.5 by phosphate buffer solution.

7. The method for rapidly culturing the aerobic granular sludge for synchronous denitrification and degradation of pyridine according to any one of claims 1 to 6, wherein the method comprises the following steps: the adopted culture device comprises an SBR reactor, a water inlet system, a drainage system, an aeration system, a DO online monitor and a PLC control system; the SBR reactor is a cylindrical double-layer organic glass cylinder with the height-diameter ratio of 15-18, circulating water can be introduced into the outer layer for water bath heat preservation, a plurality of valves for water inlet, air inlet, water discharge, sampling and sludge discharge are arranged on the inner layer, and an exhaust port is positioned right above the SBR reactor; the water inlet system comprises a water inlet barrel, a water inlet pipe and a peristaltic pump, and the water inlet is arranged at the bottom of the reactor; the water outlet is positioned in the middle of the reactor, ensures that the volume exchange ratio of water is 50% each time, is connected with a normally closed electromagnetic valve and is controlled by a PLC control system; the aeration system comprises an air compressor, a gas flowmeter and a cylindrical microporous aeration head, wherein the aeration head and an air inlet are positioned at the bottom of the reactor; one end of the DO on-line monitor is directly inserted into the reactor main body, and the other end is connected with the PLC control system.