Continuous flow urban sewage granular sludge self-enrichment coupled autotrophic biological membrane deep nitrogen and phosphorus removal method

Abstract

The invention discloses a continuous flow urban sewage granular sludge self-enrichment coupled autotrophic biological membrane deep nitrogen and phosphorus removal method, which comprises the following steps: inoculating a deep nitrogen and phosphorus removal device with floc whole-process nitrification sludge with the concentration of 2500-4500 mg / L, then filling sewage, enabling the floc whole-process nitrification sludge to be self-gathered into short-process nitrification granular sludge, starting sludge circulation, and carrying out secondary nitrification on the short-process nitrification granular sludge to obtain the short-process nitrification granular sludge. Sewage and granular sludge are mixed through an instantaneous mixing pipe and then enter a first mixing area, the nitrite accumulation amount is monitored, when short-cut nitrification is destroyed, an alkali liquor hydrazine composite NOB inhibitor is added into a second mixing area, the DO concentration of an aerobic area and the DO concentration of an anaerobic ammonia oxidation area are monitored and controlled, and the nitrite concentration is made to be lower than 0.8 mg / L. According to the method, short-cut nitrification of the granular sludge in the continuous flow urban sewage is realized, short-cut nitrification and denitrification of the granular sludge and deep nitrogen and phosphorus removal through coupling of anaerobic ammonia oxidation are realized, and the technical bottlenecks that the continuous flow granular sludge is difficult to culture, the short-cut nitrification granular sludge is difficult to realize, and the granular sludge and anaerobic ammonia oxidation coupled nitrogen removal is difficult to realize are broken through.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and more specifically, relates to a method for deep nitrogen and phosphorus removal by coupling self-enrichment of granular sludge of continuous-flow urban sewage with autotrophic biofilm. Background Art

[0003] At present, phosphorus in sewage can be removed efficiently by chemical methods, while nitrogen removal is mainly based on biological methods. Efficient nitrogen removal is an international problem in the field of water pollution control. Traditional nitrification and denitrification processes have technical problems such as high aeration energy consumption, reliance on external carbon sources, and large sludge production, which leads to complex sewage treatment processes, low efficiency, difficulty in meeting standards, and high construction and operation costs. It is a "high-cost pollution control" sewage treatment method. Therefore, low-energy and high-efficiency sewage denitrification technology urgently needs to be developed and promoted.

[0004] The anaerobic ammonium oxidation process has greatly broken through the traditional nitrification-denitrification process framework in terms of concept and technology. Anaerobic ammonium oxidizing bacteria use nitrite as an electron acceptor to oxidize ammonia nitrogen to generate nitrogen gas, and use inorganic carbon as a carbon source, without the need for organic matter as a carbon source, thereby achieving autotrophic biological denitrification. Compared with traditional biological denitrification, short-range nitrification / anaerobic ammonium oxidation autotrophic denitrification can reduce aeration volume by 60% and carbon source dosage by 100%. At present, the anaerobic ammonium oxidation process has been successfully applied on a large scale to the treatment of high-ammonia nitrogen wastewater such as sludge digestion liquid, landfill leachate, aquaculture wastewater, and pharmaceutical wastewater, but there are still many technical difficulties that need to be overcome in the actual application of this technology in urban sewage.

[0005] Aerobic granular sludge is a microbial aggregate formed under specific conditions. Compared with traditional activated sludge, aerobic granular sludge has a dense structure, a sedimentation rate that is 5 to 10 times that of ordinary activated sludge, saves 20% to 70% of floor space, and can increase water load by more than 20%; the abundance of functional bacteria is increased by 2 to 3 times, the biochemical reaction efficiency is high, the shock load resistance is strong, and the effluent quality is good; the process flow is short, and energy consumption is reduced by 20% to 35%; the simultaneous denitrification and phosphorus removal effects are good, and the drug consumption is saved by 60% to 80%; it is suitable for treating both domestic sewage and industrial wastewater; currently, aerobic granular sludge technology has been applied in the SBR process of urban sewage treatment plants, but the difficulties of this technology in continuous flow urban sewage treatment have not been overcome. Summary of the invention

[0006] The purpose of the present invention is to address the deficiencies in the prior art and provide a method for deep denitrification and phosphorus removal by continuous flow urban sewage granular sludge self-enrichment coupled with autotrophic biofilm, so as to solve the problems of unstable operation, poor effluent quality, high operating costs, low treatment load and large greenhouse gas emissions of existing urban sewage devices.

[0007] In order to achieve the above object, the present invention provides a method for continuous flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilm deep denitrification and phosphorus removal, comprising:

[0008] The first mixing zone, the second mixing zone, the aerobic zone, and the anaerobic ammonium oxidation zone connected in sequence by overflow constitute a deep denitrification and phosphorus removal device. The anaerobic ammonium oxidation zone is provided with an anaerobic ammonium oxidation biofilm. The overflow of the deep denitrification and phosphorus removal device is connected to a sedimentation tank. The sedimentation tank is connected to the first mixing zone by a transient mixing pipe to form a sludge circulation.

[0009] S1. The deep denitrification and phosphorus removal device is inoculated with flocculent full-process nitrification sludge at a concentration of 2500-4500 mg / L and then filled with sewage to make the flocculent full-process nitrification sludge self-aggregate into short-range nitrification granular sludge. The average particle size of the short-range nitrification granular sludge is 120-250 μm, and SVI is 50-75;

[0010] The effluent of the deep denitrification and phosphorus removal device is stable for 15 days, with effluent ammonia nitrogen lower than 1.5mg / L, effluent TN lower than 7mg / L, effluent COD lower than 30mg / L, effluent TP lower than 0.3mg / L, and TN average removal load not less than 0.1kg·N / m 3 / d;

[0011] S2, start the sludge circulation, sewage and granular sludge are mixed in the instantaneous mixing tube and then enter the first mixing zone;

[0012] The contact mixing time of sewage and short-range nitrification granular sludge in the instantaneous mixing tube is 5±1s, the hydraulic retention time of the first mixing zone and the second mixing zone is 25±1min respectively, and the sludge return ratio is 50-150%;

[0013] If the average particle size of the short-range nitrification granular sludge is lower than 120 μm, the contact mixing time of the sewage and granular sludge in the instantaneous mixing tube is adjusted to 15-20 seconds, the hydraulic retention time of the first mixing zone is 0-15 minutes, the hydraulic retention time of the second mixing zone is 0-20 minutes, and the sludge return ratio is 0-100%, until the average particle size of the short-range nitrification granular sludge is restored to above 120 μm;

[0014] S3, monitor the accumulation of nitrite, and add alkali solution and ammonia compound NOB inhibitor in the second mixing zone when the short-range nitrification is destroyed;

[0015] When the effluent TN of the deep denitrification and phosphorus removal device is greater than 12mg / L, the ammonia nitrogen concentration is greater than 4mg / L, and the nitrate nitrogen concentration is greater than 4mg / L, add alkali solution and ammonia compound NOB inhibitor to make the effluent TN of the deep denitrification and phosphorus removal device less than 7mg / L, the ammonia nitrogen concentration is less than 1.5mg / L, and the nitrate nitrogen concentration is less than 1.5mg / L;

[0016] S4. Monitor and control the DO concentration in the aerobic zone and the anaerobic ammonium oxidation zone to keep the nitrite concentration below 0.8 mg / L;

[0017] The DO concentration in the aerobic zone is 1.5-2.5 mg / L. When the nitrite concentration in the aerobic zone is greater than 0.8 mg / L, the DO concentration in the aerobic zone gradually decreases to 1.5 mg / L.

[0018] The DO concentration in the anaerobic ammonium oxidation zone is 0.1-0.5 mg / L. When the effluent ammonia nitrogen concentration is greater than 1.5 mg / L, the DO concentration at the end of the anaerobic ammonium oxidation zone is increased to 0.3 mg / L. When the effluent ammonia nitrogen concentration is lower than 1.5 mg / L, the DO concentration at the end of the anaerobic ammonium oxidation zone is 0.1-0.2 mg / L.

[0019] Optionally, the concentration of the alkali solution hydrazine combined NOB inhibitor in the second mixing zone is 0.8-1.5 mgN / L.

[0020] Optionally, the alkaline hydrazine composite NOB inhibitor is prepared by mixing hydrazine sulfate and sodium bicarbonate in a ratio of 0.5:1 to 1:1.

[0021] Optionally, the sludge age of the deep nitrogen and phosphorus removal device is 12-20 days.

[0022] Optionally, it also includes: the hydraulic retention time of the deep denitrification and phosphorus removal device is controlled at 4.5 to 8.5 hours.

[0023] Optionally, it also includes: the angle between the sewage in the instantaneous mixing pipe and the granular sludge pipe is 60° to 90°.

[0024] The present invention provides a method for deep nitrogen and phosphorus removal by self-enrichment of continuous-flow municipal sewage granular sludge coupled with autotrophic biofilm, which has the following beneficial effects:

[0025] This method, without adding any external agents and without controlling the influent C / N and temperature, self-enriches dense regular round granular sludge in a continuous flow urban sewage deep denitrification and phosphorus removal device, and realizes continuous flow urban sewage short-term nitrification granular sludge through alkali solution and ammonia composite NOB inhibitor, and realizes deep denitrification and phosphorus removal by coupling short-term nitrification and denitrification of granular sludge with anaerobic ammonia oxidation, breaking through the technical bottlenecks of continuous flow granular sludge cultivation difficulty, short-term nitrification granular sludge realization difficulty, and granular sludge and anaerobic ammonia oxidation coupling denitrification difficulty.

[0026] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0028] Figure 1 A schematic structural diagram of a deep denitrification and phosphorus removal device for a method of deep denitrification and phosphorus removal using continuous-flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilm according to an embodiment of the present invention is shown.

[0029] Figure 2 A schematic diagram of granular sludge in a method of continuous flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilm deep denitrification and phosphorus removal according to an embodiment of the present invention is shown.

[0030] Figure 3 A schematic diagram of a curve showing changes in effluent water quality of a method for continuous flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilm deep denitrification and phosphorus removal according to an embodiment of the present invention is shown.

[0031] Description of reference numerals:

[0032] 1. Urban sewage device; 2. Deep denitrification and phosphorus removal device; 3. Sedimentation device; 4. Alkaline hydrazine composite solution device;

[0033] 1.1, sewage tank; 1.2, overflow pipe; 1.3, sewage delivery pump;

[0034] 2.1, sewage and sludge instant mixing pipe; 2.2, first mixing zone; 2.3, second mixing zone; 2.4, aerobic zone; 2.5, anaerobic ammonium oxidation zone; 2.6, online instrument; 2.7, air pump; 2.8, variable speed mixer; 2.9, aeration device; 2.10, first gas flow meter; 2.11, first DO sensor; 2.12, second gas flow meter; 2.13, third gas flow meter; 2.14, second DO sensor; 2.15, third DO sensor; 2.16, ammonia nitrogen and nitrate nitrogen sensor; 2.17, anaerobic ammonium oxidation biofilm;

[0035] 3.1, sedimentation tank; 3.2, sludge return pump; 3.3, residual sludge discharge pump; 3.4, outlet pipe;

[0036] 4.1. Alkaline hydrazine compound solution tank; 4.2. Mixer; 4.3. Metering delivery pump. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0038] like Figure 1-3 As shown, a device for cultivating integrated short-range nitrification anaerobic ammonium oxidation granular sludge comprises:

[0039] The first mixing zone, the second mixing zone, the aerobic zone, and the anaerobic ammonium oxidation zone connected in sequence by overflow constitute a deep denitrification and phosphorus removal device. The anaerobic ammonium oxidation zone is provided with an anaerobic ammonium oxidation biofilm. The overflow of the deep denitrification and phosphorus removal device is connected to a sedimentation tank. The sedimentation tank is connected to the first mixing zone by a transient mixing pipe to form a sludge circulation.

[0040] S1. The deep denitrification and phosphorus removal device is inoculated with flocculent full-process nitrification sludge at a concentration of 2500-4500 mg / L and then filled with sewage to make the flocculent full-process nitrification sludge self-aggregate into short-range nitrification granular sludge. The average particle size of the short-range nitrification granular sludge is 120-250 μm, and SVI is 50-75;

[0041] The effluent of the deep denitrification and phosphorus removal device is stable for 15 days, with effluent ammonia nitrogen lower than 1.5mg / L, effluent TN lower than 7mg / L, effluent COD lower than 30mg / L, effluent TP lower than 0.3mg / L, and TN average removal load not less than 0.1kg·N / m 3 / d;

[0042] S2, start the sludge circulation, sewage and granular sludge are mixed in the instantaneous mixing tube and then enter the first mixing zone;

[0043] The contact mixing time of sewage and short-range nitrification granular sludge in the instantaneous mixing tube is 5±1s, the hydraulic retention time of the first mixing zone and the second mixing zone is 25±1min respectively, and the sludge return ratio is 50-150%;

[0044] If the average particle size of the short-range nitrification granular sludge is lower than 120 μm, the contact mixing time of the sewage and granular sludge in the instantaneous mixing tube is adjusted to 15-20 seconds, the hydraulic retention time of the first mixing zone is 0-15 minutes, the hydraulic retention time of the second mixing zone is 0-20 minutes, and the sludge return ratio is 0-100%, until the average particle size of the short-range nitrification granular sludge is restored to above 120 μm;

[0045] S3, monitor the accumulation of nitrite, and add alkali solution and ammonia compound NOB inhibitor in the second mixing zone when the short-range nitrification is destroyed;

[0046] When the effluent TN of the deep denitrification and phosphorus removal device is greater than 12mg / L, the ammonia nitrogen concentration is greater than 4mg / L, and the nitrate nitrogen concentration is greater than 4mg / L, add alkali solution and ammonia compound NOB inhibitor to make the effluent TN of the deep denitrification and phosphorus removal device less than 7mg / L, the ammonia nitrogen concentration is less than 1.5mg / L, and the nitrate nitrogen concentration is less than 1.5mg / L;

[0047] S4. Monitor and control the DO concentration in the aerobic zone and the anaerobic ammonium oxidation zone to keep the nitrite concentration below 0.8 mg / L;

[0048] The DO concentration in the aerobic zone is 1.5-2.5 mg / L. When the nitrite concentration in the aerobic zone is greater than 0.8 mg / L, the DO concentration in the aerobic zone gradually decreases to 1.5 mg / L.

[0049] The DO concentration in the anaerobic ammonium oxidation zone is 0.1-0.5 mg / L. When the effluent ammonia nitrogen concentration is greater than 1.5 mg / L, the DO concentration at the end of the anaerobic ammonium oxidation zone is increased to 0.3 mg / L. When the effluent ammonia nitrogen concentration is lower than 1.5 mg / L, the DO concentration at the end of the anaerobic ammonium oxidation zone is 0.1-0.2 mg / L.

[0050] Specifically, the method can be divided into a preparation phase and a processing phase, in which:

[0051] Preparation stage: Based on the non-short-term nitrification granular sludge, short-term nitrification granular sludge is cultivated by floc full-process nitrification sludge.

[0052] The deep denitrification and phosphorus removal device is inoculated with flocculent sludge and anaerobic ammonium oxidation biofilm. The sewage is removed from the deep denitrification and phosphorus removal device, and the muddy water mixture of COD, TP and TN enters the sedimentation device. The treated water after sedimentation is discharged, including:

[0053] Instant mixing tube: instant contact between sewage and sludge creates favorable conditions for bacterial aggregation;

[0054] The first mixing zone: short-term mixing, uniform bacterial aggregation and anaerobic phosphorus release;

[0055] The second mixing zone: short-term mixing, uniform bacterial aggregation and anaerobic phosphorus release;

[0056] Aerobic zone: complete biological carbon and phosphorus removal and carry out partial short-range nitrification;

[0057] Anaerobic ammonium oxidation zone: granular sludge short-term nitrification and denitrification and autotrophic anaerobic ammonium oxidation deep denitrification;

[0058] Sedimentation tank: for separation of mud and water.

[0059] Treatment stage: The sludge circulation is started to circulate the short-range nitrification granular sludge.

[0060] The instantaneous mixing tube for sewage and sludge in the deep denitrification and phosphorus removal device realizes instantaneous contact between sewage and sludge, allowing sewage and granular sludge to fully contact. Sewage impurities and granular sludge debris in the instantaneous mixing tube coagulate to increase the degree of granulation. At the same time, the intense mixing contact also causes a feast / starvation reaction.

[0061] After that, the urban sewage mixed with granular sludge enters the first mixing zone and the second mixing zone in turn, so that the sewage and sludge are mixed evenly in a short time, thereby creating favorable conditions for bacterial aggregation and achieving anaerobic phosphorus release. The particle size of the granular sludge is monitored during the process, and the progress of the water treatment reaction is judged by the state of the granular sludge to ensure the stable operation of short-range nitrification.

[0062] If any problem occurs, add alkali solution and ammonia combined with NOB inhibitor for regulation, and confirm the regulation effect based on the effluent quality.

[0063] At the same time, the DO concentration can be controlled in the aerobic zone and the anaerobic ammonium oxidation zone to keep the nitrite accumulation below 0.8 mg / L, greatly reducing the emission of greenhouse gas N2O.

[0064] Furthermore, the floc sludge self-aggregates to achieve granulation, and the alkali solution and ammonia compound NOB inhibitor are strategically added in the second mixing zone to achieve stable short-term nitrification of the system, that is, short-term nitrification granular sludge. Not only does the granular sludge continuously provide a stable matrix for the anaerobic ammonia-oxidizing bacteria to complete deep denitrification, but the granular sludge itself also completes denitrification, that is, the continuous flow granular sludge self-enrichment and autotrophic biofilm coupling deep denitrification and phosphorus removal are achieved, breaking through the difficulties of continuous flow granular sludge self-enrichment and the coupling denitrification of granular sludge and autotrophic anaerobic ammonia oxidation.

[0065] In this embodiment, the concentration of the alkali solution hydrazine combined NOB inhibitor in the second mixing zone is 0.8-1.5 mgN / L.

[0066] Specifically, the addition of alkali solution and ammonia combined with NOB inhibitor shortens the sludge age. The normal sludge age is 12-20 days, and the sludge age is shortened to 12 days when adding, until the effluent TN is less than 7mg / L, the ammonia nitrogen concentration is less than 1.5mg / L, and the nitrate nitrogen concentration is less than 1.5mg / L, that is, short-term nitrification is restored.

[0067] Furthermore, the concentration of the alkaline hydrazine complex solution is controlled at 0.8-1.5 mgN / L, which greatly improves the selective inhibition of NOB without significantly affecting the activity of other bacterial flora, and can quickly achieve stable short-range nitrification.

[0068] In this embodiment, the alkali-hydrazine composite NOB inhibitor is prepared by mixing hydrazine sulfate and sodium bicarbonate in a ratio of 0.5:1 to 1:1.

[0069] Specifically, the inhibitor is prepared by mixing hydrazine sulfate and sodium bicarbonate in a ratio of 0.5:1 to 1:1. The inhibitor has the advantages of convenient configuration, small dosage, high inhibition efficiency, etc., and realizes stable short-range nitrification of the system. The inhibition effect is better than that of traditional hydrazine sulfate solution, and the comprehensive cost is lower than that of traditional hydrazine sulfate solution.

[0070] In this embodiment, the sludge age of the deep denitrification and phosphorus removal device is 12-20 days.

[0071] Specifically, 4) the hydraulic retention time of the deep denitrification and phosphorus removal device is controlled at 4.5 to 8.5 hours, the temperature is 14 to 27° C., and a normal temperature environment can be used.

[0072] In this embodiment, it also includes: the hydraulic retention time of the deep denitrification and phosphorus removal device is controlled at 4.5 to 8.5 hours.

[0073] In this embodiment, it also includes: the angle between the sewage in the instantaneous mixing pipe and the granular sludge pipe is 60° to 90°.

[0074] Specifically, the mixing angle of sewage and granular sludge is controlled to accelerate the mixing of the two, avoid mutual backflow to break up sludge particles and slow down the flow rate.

[0075] Example

[0076] The deep denitrification and dephosphorization device 2 is connected to the urban sewage device 1 and the sedimentation device 3 in front and back, and is provided with an alkaline hydrazine composite solution device 4 for adding an alkaline hydrazine composite NOB inhibitor.

[0077] The urban sewage device 1 includes a sewage tank 1.1, an overflow pipe 1.2, and a sewage delivery pump 1.3; the deep denitrification and phosphorus removal device 2 includes a sewage and sludge instantaneous mixing pipe 2.1, a first mixing zone 2.2, a second mixing zone 2.3, an aerobic zone 2.4, an anaerobic ammonia oxidation zone 2.5, an online instrument 2.6, and an air pump 2.7; the sewage delivery pump 1.3 is connected to the sewage and sludge instantaneous mixing pipe 2.1, the sewage and sludge instantaneous mixing pipe 2.1 is connected to the first mixing zone 2.2, the first mixing zone 2.2 is connected to the second mixing zone 2.3, and the second mixing zone 2 .3 is connected to the aerobic zone 2.4, the aerobic zone 2.4 is connected to the anaerobic ammonium oxidation zone 2.5, and the anaerobic ammonium oxidation zone 2.5 is connected to the sedimentation device 3; the first mixing zone 2.2 and the second mixing zone 2.3 are both equipped with a variable speed mixer 2.8; the aerobic zone 2.4 is equipped with an aeration device 2.9, a first gas flow meter 2.10, and a first DO sensor 2.11; the anaerobic ammonium oxidation zone 2.5 is equipped with an aeration device 2.9, a second gas flow meter 2.12, a third gas flow meter 2.13, a second DO sensor 2.14, and a third online DO sensor 2 .15, ammonia nitrogen and nitrate nitrogen sensor 2.16, anaerobic ammonia oxidation biofilm 2.17; the online instrument 2.6 is respectively connected to the first DO sensor 2.11, the second DO sensor 2.14, the third DO sensor 2.15, and the online ammonia nitrogen and nitrate nitrogen sensor 2.16; the air pump 2.7 is respectively connected to the first gas flow meter 2.10, the second gas flow meter 2.12, the third gas flow meter 2.13 and the aeration device 2.9; the sedimentation device 3 includes a sedimentation tank 3.1, a sludge return pump 3.2, a residual sludge discharge pump 3.3, and an outlet water pipe 3.4; the sedimentation tank 3.1 is connected to the first mixing zone 2.2 through a sludge return pump 3.2, the sedimentation tank 3.1 is connected to the sewage and sludge instantaneous mixing pipe 2.1 through a residual sludge discharge pump 3.3, and the effluent from the sedimentation tank 3.1 is discharged through the outlet pipe 3.4; the alkaline hydrazine composite solution device 4 includes an alkaline hydrazine composite solution tank 4.1, a mixer 4.2, and a metering delivery pump 4.3; the alkaline hydrazine composite solution tank 4.1 is connected to the second mixing zone 2.3 through a metering delivery pump 4.3; the alkaline hydrazine composite solution tank 4.1 is installed with a mixer 4.2.

[0078] The deep denitrification and phosphorus removal device 2 utilizes the sewage and sludge instantaneous mixing tube 2.1 to achieve instantaneous contact between sewage and sludge, and enters the first mixing zone 2.2 and the second mixing zone 2.3 to achieve short-term uniform mixing of sewage and sludge, thereby creating favorable conditions for bacterial aggregation and achieving anaerobic phosphorus release at the same time. The DO concentration is controlled in the aerobic zone 2.4 and the anaerobic ammonia oxidation zone 2.5 to achieve nitrite accumulation below 0.8 mg / L, greatly reducing the emission of greenhouse gas N2O. Through the control and operation of the system, the system floc sludge self-aggregates to achieve granulation, the average particle size reaches more than 120 μm, the particles are dense regular round, and SVI=50~75. In addition, by strategically adding alkaline solution and ammonia combined NOB inhibitor in the second mixing zone 2.3, stable short-term nitrification of the system is achieved, that is, short-term nitrification granular sludge is achieved. Not only does the granular sludge continuously provide a stable substrate for anaerobic ammonia-oxidizing bacteria to complete denitrification, but the granular sludge itself also completes denitrification, that is, the continuous flow granular sludge self-enrichment and autotrophic biofilm coupling deep denitrification and phosphorus removal are achieved. The realization of this system has broken through the difficulties of continuous flow granular sludge and the coupling denitrification of granular sludge and autotrophic anaerobic ammonia oxidation.

[0079] The effluent from the primary sedimentation tank of a sewage treatment plant in Beijing is taken as urban sewage, and the water quality is shown in Table 1.

[0080] Table 1 Urban sewage quality

[0081]

[0082] Note: The above indicators are in mg / L, and the water samples are not filtered;

[0083] 1) Inoculating common floc full nitrification sludge in the first mixing zone 2.2, the second mixing zone 2.3, the aerobic zone 2.4, and the anaerobic ammonium oxidation zone 2.5 in the deep denitrification and phosphorus removal device 2, and maintaining the common floc full nitrification sludge concentration in the first mixing zone 2.2, the second mixing zone 2.3, the aerobic zone 2.4, and the anaerobic ammonium oxidation zone 2.5 at 3000-3500 mg / L; inoculating the anaerobic ammonium oxidation biofilm 2.17 of the anaerobic ammonium oxidation biofilm in the anaerobic ammonium oxidation zone 2.5, with a filling ratio of 25%; the urban sewage flows through the sewage and sludge instant mixing pipe 2.1, the first mixing zone 2.2, the second mixing zone 2.3, the aerobic zone 2.4, the anaerobic ammonium oxidation zone 2.5, and the sedimentation tank 3.1 in sequence through the urban sewage device, and the sewage and sludge are instantaneously The contact creates favorable conditions for bacterial aggregation, short-term mixing and uniform bacterial aggregation and anaerobic phosphorus release, short-term mixing and uniform bacterial aggregation and anaerobic phosphorus release, completes biological carbon removal and phosphorus removal and performs partial short-term nitrification, performs granular sludge short-term nitrification and denitrification and autotrophic anaerobic ammonia oxidation deep denitrification, performs mud and water separation, and deeply removes total nitrogen, phosphorus and organic matter in sewage; when the ordinary flocculent full-time nitrification sludge in the deep denitrification and phosphorus removal device 2 is converted into short-term nitrification granular sludge with an average particle size of 120μm to 250μm, SVI = 50-75, effluent ammonia nitrogen is less than 1.5mg / L, effluent TN is less than 7mg / L, effluent COD is less than 30mg / L, effluent TP is less than 0.3mg / L, and the average TN removal load is not less than 0.1kg·N / m 3 / d and has been running stably for more than 15 days, it is considered that the continuous flow municipal sewage granular sludge self-enrichment coupled autotrophic biofilm deep denitrification and phosphorus removal process has been successfully started and achieved stable operation.

[0084] 2) The sludge in the sedimentation tank 3.1 is returned to the sewage and sludge instantaneous mixing pipe 2.1 through the sludge return pump 3.2 for instantaneous mixing with urban sewage, the instantaneous contact time is 5s, the residence time in the first mixing zone 2.2 and the second mixing zone 2.3 are both 25min, the sludge return ratio is 50% to 150%, and when the average particle size of the granular sludge in the deep denitrification and phosphorus removal device 2 is lower than 120μm, the instantaneous contact time between the urban sewage and the returned sludge in the sewage and sludge instantaneous mixing pipe 2.1 is adjusted to not less than 15s, the residence time in the first mixing zone 2.2 is shortened to no more than 15min, the residence time in the second mixing zone 2.3 is shortened to no more than 20min, and the sludge return ratio is not more than 100%, until the average particle size of the granular sludge is restored to above 120μm.

[0085] 3) The sludge age of the deep denitrification and phosphorus removal device 2 is controlled at 12 to 20.0 days. When the effluent TN is greater than 12 mg / L, the ammonia nitrogen concentration is greater than 4 mg / L, the nitrate nitrogen concentration is greater than 4 mg / L, and the nitrite concentration is less than 1.5 mg / L, it indicates that the accumulated nitrite in the deep denitrification and phosphorus removal device is insufficient to supply anaerobic ammonia oxidation and granular sludge for denitrification, that is, the short-range nitrification is destroyed. Immediately start the metering delivery pump 4.3 of the alkaline hydrazine composite solution device 4, add the alkaline hydrazine composite solution to the second mixing zone 2.3, control the concentration of the alkaline hydrazine composite solution in the second mixing zone 2.3 to 1.0 mgN / L, shorten the sludge age to 12 days, until the effluent TN is less than 7 mg / L, the ammonia nitrogen concentration is less than 1.5 mg / L, and the nitrate nitrogen concentration is less than 1.5 mg / L, that is, the short-range nitrification is restored, close the metering delivery pump 4.3, and stop adding the alkaline hydrazine composite solution.

[0086] 4) The hydraulic retention time of deep denitrification and phosphorus removal device 2 is controlled at 4.5-8.5h, the temperature is 14-27℃, the 2.4DO concentration in the aerobic zone is controlled at 1.5-2.5mg / L, when the 2.4 nitrite concentration in the aerobic zone is higher than 0.8mg / L, the 2.4DO concentration in the aerobic zone is gradually reduced to 1.5mg / L, and the 2.4 nitrite concentration in the aerobic zone is maintained below 0.8mg / L; the 2.5DO concentration in the anaerobic ammonia oxidation zone is 0.1-0.5mg / L, and the concentration is gradually reduced to 1.5mg / L. In the direction of water flow, DO concentration shows a decreasing trend. When the effluent ammonia nitrogen concentration is higher than 1.5 mg / L, the DO concentration at the end of anaerobic ammonium oxidation zone 2.5 is increased to 0.3 mg / L. When the effluent ammonia nitrogen concentration is lower than 1.5 mg / L, the DO concentration at the end of anaerobic ammonium oxidation zone 2.5 is 0.1-0.2 mg / L. By controlling the DO concentration, the nitrite concentration in the deep denitrification and phosphorus removal device is maintained below 0.8 mg / L, thereby greatly reducing the emission of greenhouse gas N2O.

[0087] This method achieves high-quality effluent water quality by coupling the self-enrichment of granular sludge with autotrophic biofilm to remove nitrogen and phosphorus. The effluent ammonia nitrogen is less than 1.5 mg / L, the effluent TN is less than 7 mg / L, the effluent COD is less than 30 mg / L, and the effluent TP is less than 0.3 mg / L. The average TN removal load is as high as 0.1-0.2 kg·N / m 3 / d, which is about 2 to 4 times the existing urban sewage denitrification process.

[0088] At the same time, it can greatly save treatment costs, save land, and greatly reduce greenhouse gas emissions. It is a new type of green, low-carbon and efficient sewage denitrification process. It is simple to operate and transform, and is easy to apply to new or renovated sewage treatment plants.

[0089] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for deep nitrogen and phosphorus removal by continuous flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilm, characterized in that: include: The first mixing zone, the second mixing zone, the aerobic zone, and the anaerobic ammonium oxidation zone connected in sequence by overflow constitute a deep denitrification and phosphorus removal device. The anaerobic ammonium oxidation zone is provided with an anaerobic ammonium oxidation biofilm. The overflow of the deep denitrification and phosphorus removal device is connected to a sedimentation tank. The sedimentation tank is connected to the first mixing zone by a transient mixing pipe to form a sludge circulation. S1. The deep denitrification and phosphorus removal device is inoculated with flocculent full-process nitrification sludge at a concentration of 2500-4500 mg / L and then filled with sewage to make the flocculent full-process nitrification sludge self-aggregate into short-range nitrification granular sludge. The average particle size of the short-range nitrification granular sludge is 120-250 μm, and SVI is 50-75; The effluent of the deep denitrification and phosphorus removal device is stable for 15 days, with effluent ammonia nitrogen lower than 1.5mg / L, effluent TN lower than 7mg / L, effluent COD lower than 30mg / L, effluent TP lower than 0.3mg / L, and TN average removal load not less than 0.1kg·N / m 3 / d; S2, start the sludge circulation, sewage and granular sludge are mixed in the instantaneous mixing tube and then enter the first mixing zone; The contact mixing time of sewage and short-range nitrification granular sludge in the instantaneous mixing tube is 5±1s, the hydraulic retention time of the first mixing zone and the second mixing zone is 25±1min respectively, and the sludge return ratio is 50-150%; If the average particle size of the short-range nitrification granular sludge is lower than 120 μm, the contact mixing time of the sewage and granular sludge in the instantaneous mixing tube is adjusted to 15-20 seconds, the hydraulic retention time of the first mixing zone is 0-15 minutes, the hydraulic retention time of the second mixing zone is 0-20 minutes, and the sludge return ratio is 0-100%, until the average particle size of the short-range nitrification granular sludge is restored to above 120 μm; S3, monitor the accumulation of nitrite, and add alkali solution and ammonia compound NOB inhibitor in the second mixing zone when the short-range nitrification is destroyed; When the effluent TN of the deep denitrification and phosphorus removal device is greater than 12mg / L, the ammonia nitrogen concentration is greater than 4mg / L, and the nitrate nitrogen concentration is greater than 4mg / L, add alkali solution and ammonia compound NOB inhibitor to make the effluent TN of the deep denitrification and phosphorus removal device less than 7mg / L, the ammonia nitrogen concentration is less than 1.5mg / L, and the nitrate nitrogen concentration is less than 1.5mg / L; S4. Monitor and control the DO concentration in the aerobic zone and the anaerobic ammonium oxidation zone to keep the nitrite concentration below 0.8 mg / L; The DO concentration in the aerobic zone is 1.5-2.5 mg / L. When the nitrite concentration in the aerobic zone is greater than 0.8 mg / L, the DO concentration in the aerobic zone gradually decreases to 1.5 mg / L. The DO concentration in the anaerobic ammonium oxidation zone is 0.1-0.5 mg / L. When the effluent ammonia nitrogen concentration is greater than 1.5 mg / L, the DO concentration at the end of the anaerobic ammonium oxidation zone is increased to 0.3 mg / L. When the effluent ammonia nitrogen concentration is lower than 1.5 mg / L, the DO concentration at the end of the anaerobic ammonium oxidation zone is 0.1-0.2 mg / L.

2. The method of continuous flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilm deep denitrification and phosphorus removal according to claim 1, characterized in that: The concentration of the alkaline solution hydrazine compound NOB inhibitor in the second mixing zone is 0.8-1.5 mgN / L.

3. The method for continuous flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilm deep denitrification and phosphorus removal according to claim 1, characterized in that: The alkaline hydrazine composite NOB inhibitor is prepared by mixing hydrazine sulfate and sodium bicarbonate in a ratio of 0.5:1 to 1:

1.

4. The method for continuous flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilm deep denitrification and phosphorus removal according to claim 1, characterized in that: The sludge age of the deep nitrogen and phosphorus removal device is 12-20 days.

5. The method of continuous flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilm deep denitrification and phosphorus removal according to claim 1, characterized in that: Also includes: The hydraulic retention time of the deep denitrification and phosphorus removal device is controlled at 4.5 to 8.5 hours.

6. The method of continuous flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilm deep denitrification and phosphorus removal according to claim 1, characterized in that: Also includes: The angle between the sewage in the instantaneous mixing tube and the granular sludge tube is 60° to 90°.

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