Sulfur autotrophic denitrification dynamic membrane bioreactor and method for treating nitrogen-containing wastewater using the same

Abstract

The application provides a sulfur autotrophic denitrification dynamic membrane bioreactor, which is provided with a reaction zone, so that nitrogen-containing wastewater to be treated mixed with sulfur particles and activated sludge is continuously led out after passing through a membrane assembly in the reaction zone, forming a dynamic membrane, and then the nitrogen-containing wastewater is subjected to denitrification treatment. The service life of the dynamic membrane is effectively prolonged, the cost is low, the wastewater can be efficiently subjected to denitrification treatment, and the use requirement is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sewage denitrification treatment, and particularly relates to a denitrification method using a sulfur autotrophic denitrification dynamic membrane bioreactor. BACKGROUND

[0002] Water body eutrophication not only reduces the ornamental value of the water body, but also harms the survival of organisms, is a more prominent phenomenon in surface water pollution problems, and has high treatment costs. The increase of nitrogen elements is one of the fundamental reasons for eutrophication, in which nitrate is the main pollutant. When the content of NO3 - and NO2 - in drinking water is too high, it will increase the risk of various diseases suffered by drinkers and harm human health. How to efficiently denitrify is not only the focus of attention of government departments at all levels, but also the difficulty of water environment governance.

[0003] Sulfur autotrophic denitrification is a denitrification reaction under the action of autotrophic denitrification bacteria such as denitrifying sulfur bacteria, with elemental sulfur, S2O3 2- and S 2- as the electron donor, and NO3 - or NO2 - as the electron acceptor. Because it does not need to add organic carbon source, has low operation cost, and produces less sludge, it has become a promising process for treating wastewater containing NO3 - . Among them, elemental sulfur has been widely concerned and researched in recent years due to its small biological toxicity, low price, easy storage and transportation and other advantages. Studies have shown that using elemental sulfur with a larger specific surface area, i.e., smaller particle size, as an electron donor can achieve a high denitrification rate. However, small-particle-size elemental sulfur is easily lost in the reaction system, and new utilization methods need to be developed urgently.

[0004] The biological treatment system combined with a membrane can achieve efficient interception of useful substances in the reaction system, often showing a high reaction rate, and has the advantages of high treatment load and small footprint. In the past, scholars have used this technology form to develop a high-efficiency membrane bioreactor (MBR) denitrification process based on chemical powder elemental sulfur as an electron donor. However, the high cost of microfiltration / ultrafiltration membranes, short membrane cycle life, and serious membrane pollution are common problems in the above MBR research, which cannot be ignored.

[0005] Therefore, based on the membrane bioreactor, it is necessary to further research and develop a denitrification method that can reduce the cost of the membrane and prolong the service life of the membrane to achieve efficient and low-cost denitrification. SUMMARY

[0006] To solve the above problems, the application provides a sulfur autotrophic denitrification dynamic membrane bioreactor and a method for denitrification using the reactor.

[0007] The application aims to provide a sulfur autotrophic denitrification dynamic membrane bioreactor, which is provided with a reaction zone, and the nitrogen-containing wastewater to be treated mixed with sulfur particles and activated sludge is discharged after passing through the membrane assembly in the reaction zone to form a dynamic membrane, and then the nitrogen-containing wastewater is subjected to denitrification treatment.

[0008] The application also aims to provide a method for treating nitrogen-containing wastewater using the sulfur autotrophic denitrification dynamic membrane bioreactor, in which sulfur particles and activated sludge are added to the nitrogen-containing wastewater in the reaction zone of the sulfur autotrophic denitrification dynamic membrane bioreactor, mixed, and subjected to denitrification treatment after forming a dynamic membrane.

[0009] The method specifically comprises the following steps:

[0010] Step 1. Sulfur particles and activated sludge are added to the nitrogen-containing wastewater in the reaction zone, and mixed by stirring to obtain the mixed wastewater to be treated;

[0011] Step 2. The mixed wastewater to be treated is passed through the membrane assembly to obtain a dynamic membrane;

[0012] Step 3. After the dynamic membrane is formed, the mixed wastewater to be treated is treated.

[0013] The sulfur autotrophic denitrification dynamic membrane bioreactor provided by the application has the following beneficial effects:

[0014] (1) The sulfur autotrophic denitrification dynamic membrane bioreactor in the application can effectively increase the membrane cycle life and control membrane pollution by adding sulfur particles and activated sludge to the nitrogen-containing wastewater, mixing, and then depositing the formed suspended particles or colloidal particles to obtain a dynamic membrane, thereby greatly saving the investment cost, and the cleaning method is simple and can be regenerated, which significantly reduces the operation and maintenance cost of the wastewater treatment process.

[0015] (2) The application uses macroporous filter material instead of microfiltration / ultrafiltration membrane, which is low in price and good in economy. Compared with the traditional microfiltration / ultrafiltration membrane technology, the application uses macroporous filter material as the supporting material, and the suspended particles or colloidal particles in the reactor are deposited on the supporting material to form a mature dynamic membrane, which replaces the microfiltration / ultrafiltration membrane and effectively intercepts the suspended particles or colloidal particles in the reactor.

[0016] (3) The composition and thickness of the dynamic membrane change dynamically with time and conditions such as operation of the bioreactor, effectively increasing the cycle life of the membrane and controlling membrane fouling. The dynamic membrane cleaning method described in the present application is simple and can be recycled, significantly reducing the operation and maintenance costs of the wastewater treatment process.

[0017] (4) The maximum total nitrogen removal load of the sulfur autotrophic denitrification dynamic membrane bioreactor described in the present application can reach 2.7 kgN / (m 3 ·d), and the elemental sulfur interception rate can reach 96%. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A result schematic diagram of a sulfur autotrophic denitrification dynamic membrane bioreactor of the present application is shown;

[0019] Figure 2 A photo of the dynamic membrane prepared in Example 1 of the present application is shown;

[0020] Figure 3 A curve showing the change of transmembrane pressure with filtration time when the membrane flux is selected as 100, 200, 300 L / m 2 ·h in Example 1 of the present application is shown;

[0021] Figure 4 A curve showing the change of effluent turbidity with filtration time when the membrane flux is selected as 100, 200, 300 L / m 2 ·h in Example 1 of the present application is shown;

[0022] Figure 5 (a) and Figure 5 (b) show SEM images of a clean nylon filter screen in Example 1 of the present application; Figure 5 (c) and Figure 5 (d) show SEM images of the dynamic membrane prepared in Example 1 of the present application; Figure 5 (e) and Figure 5 (f) show partial magnification SEM images of the dynamic membrane prepared in Example 1 of the present application;

[0023] Figure 6 A particle size distribution of particles in the nitrogen-containing wastewater to be treated mixed with sulfur particles 3 and activated sludge in the reaction zone in Example 1 of the present application is shown;

[0024] Figure 7 A curve showing the change of transmembrane pressure during the operation cycle of Example 2 and Comparative Example 1 is shown.

[0025] REFERENCE NUMERALS

[0026] 2 - membrane module;

[0027] 3 - sulfur particles;

[0028] 4-Inner shell;

[0029] 5-Outer shell;

[0030] 6-Water bathing area;

[0031] 7-Inlet pump;

[0032] 8-Balance level bottle;

[0033] 801-Balance Tube;

[0034] 802 - Air delivery tube;

[0035] 9-Pressure gauge;

[0036] 10 - Water pump;

[0037] 11-Agitator;

[0038] 12-Reaction Zone

[0039] 13-Water inlet tank;

[0040] 14-Inlet pipe;

[0041] 15 - Water outlet pipe;

[0042] 16-Constant temperature water bath circulation tank. Detailed Implementation

[0043] The present invention will now be described in detail through specific embodiments, and the features and advantages of the present invention will become clearer and more explicit with these descriptions.

[0044] This invention provides a sulfur autotrophic denitrification dynamic membrane bioreactor, which is equipped with a reaction zone 12, through which nitrogen-containing wastewater to be treated, mixed with sulfur particles 3 and activated sludge, is discharged after passing through the membrane module 2 in the reaction zone 12 to form a dynamic membrane, and then the nitrogen-containing wastewater is denitrified.

[0045] The membrane module 2 includes a filter membrane and a filter membrane support frame. The filter membrane is fixed by the filter membrane support frame, so that the nitrogen-containing wastewater to be treated, mixed with sulfur particles 3 and activated sludge, can be filtered through the filter membrane from one side to the other. The membrane module 2 includes several layers of filter membranes, preferably 1-5 layers, more preferably 2-3 layers, such as 2 layers.

[0046] The membrane support frame of membrane module 2 is provided with a fixing clip below it so that it can be fixed in the reaction zone 12. The filter support frame is provided with an outlet above it. The outlet is located between the filter membranes, preferably between the double filter membranes. The mixture in the reaction zone 12 needs to pass through the filter membrane of membrane module 2. After filtration by the double filter membrane, it is discharged from the outlet by a pump.

[0047] The filter membrane has a pore size of 1-150 μm, preferably a pore size of 20-75 μm, and more preferably a pore size of 20-50 μm. The pore size of the filter membrane affects the formation time of the dynamic membrane and the interception effect, and further affects the water quality after the wastewater treatment.

[0048] The filter membrane is selected from one of industrial filter cloth, non-woven fabric and nylon screen, preferably selected from non-woven fabric or nylon screen, and more preferably nylon screen. The use of nylon screen as the filter membrane is not only low in price, but also high in flux.

[0049] In the present application, after the start of the sulfur autotrophic denitrification dynamic membrane bioreactor, the nitrogen-containing wastewater enters the reaction zone 12, mixes with the sulfur particles 3 and the activated sludge, and passes through the membrane assembly 2, so that the sulfur particles 3 and the activated sludge are attached to the filter membrane of the membrane assembly 2 to form a dynamic membrane.

[0050] The sulfur autotrophic denitrification dynamic membrane bioreactor further comprises an inner shell 4, an outer shell 5, a water inlet pipe 14 and a water outlet pipe 15.

[0051] The inner shell 4 is provided with a membrane assembly 2 inside to form a reaction zone 12. Preferably, the membrane assembly 2 is arranged in the middle region of the reaction zone 12. The inner shell 4 and the outer shell 5 form a water bath zone 6 between them, and constant-temperature water is introduced into the water bath zone 6 to heat the reaction zone 12 in the inner shell 4.

[0052] The distance between the wastewater liquid surface in the reaction zone 12 and the bottom of the inner shell 4 is 0.9-1.5 times the diameter of the inner shell 4, preferably 1.0-1.4 times the diameter of the inner shell 4, and more preferably 1.0-1.2 times the diameter of the inner shell 4.

[0053] The height of the membrane assembly 2 in the vertical direction is (0.6-1.0) times the diameter of the inner shell 4, preferably (0.7-0.9) times the diameter of the inner shell 4, and more preferably (0.7-0.8) times the diameter of the inner shell 4.

[0054] The water inlet pipe 14 is arranged at the lower part of the outer shell 5 and communicates with the reaction zone 12 in the inner shell 4. The water outlet pipe 15 is arranged at the top of the outer shell 5 and communicates with the water outlet of the membrane assembly 2 in the reaction zone 12 of the inner shell 4. The nitrogen-containing wastewater to be treated enters the reaction zone 12 from the lower part of the inner shell 4 through the water inlet pipe 14, mixes with the sulfur particles 3 and the activated sludge, and is filtered and discharged from the water outlet pipe 15 after the filtration treatment.

[0055] The water bath zone 6 is connected to a constant-temperature water bath circulating tank 16, which continuously provides constant-temperature circulating water to the water bath zone 6 to ensure the reaction treatment temperature of the reaction zone 12.

[0056] Preferably, the agitator 11 is arranged in the middle of the inner shell 4 to continuously agitate the mixed nitrogen-containing wastewater and sulfur particles 3 and activated sludge in the inner part of the inner shell 4, maintain the mixed state of the nitrogen-containing wastewater and the sulfur particles 3, and form a dynamic membrane through the membrane assembly 2. The agitator 11 is selected from an axial flow agitator, a radial flow agitator, or a mixed flow agitator.

[0057] The ratio of the diameter of the stirring paddle of the agitator 11 to the diameter of the inner shell 4 is 0.3-0.7, preferably 0.4-0.6, and more preferably 0.45-0.55.

[0058] The ratio of the distance from the center line of the stirring paddle of the agitator 11 to the bottom of the inner shell 4 to the diameter of the inner shell 4 is 0.1-0.6, preferably 0.25-0.5, and more preferably 0.3-0.4.

[0059] Preferably, the sulfur autotrophic denitrification dynamic membrane bioreactor of the present application further comprises a balance water level bottle 8, and the water inlet end of the balance water level bottle 8 is connected to the water inlet bucket 13 through the water inlet pump 7. The nitrogen-containing wastewater in the water inlet bucket 13 is introduced into the balance water level bottle 8 under the action of the water inlet pump 7, and then enters the water inlet pipe 14.

[0060] The balance water level bottle 8 further comprises a balance pipe 801 and a gas guide pipe 802. The balance pipe 801 is arranged at a height higher than the water inlet end of the balance water level bottle 8, and the gas guide pipe 802 is arranged at the top of the balance water level bottle 8 to maintain the connection between the inside and the outside of the balance water level bottle 8.

[0061] The outlet of the balance water level bottle 8 connected to the water outlet of the water inlet pipe 14 is arranged at a height between the height of the balance pipe 801 and the height of the water inlet end of the balance water level bottle 8.

[0062] When the water inlet pump 7 is started, the nitrogen-containing wastewater in the water bucket 13 is continuously introduced into the balance water level bottle 8. When the internal liquid surface reaches the water outlet of the balance water level bottle 8 connected to the water inlet pipe 14, the wastewater enters the water inlet pipe 14. When the internal liquid surface reaches the water outlet of the balance water level bottle 8 connected to the balance pipe 801, part of the wastewater is guided back to the water inlet bucket 13 through the balance pipe 801, so that the water pressure of the water inlet pipe 14 is maintained within a certain range, the amount of wastewater entering the reaction zone 12 is controlled, and the membrane flux through the membrane assembly 2 is further controlled.

[0063] Preferably, the water outlet pipe 15 of the present application is connected to the pressure gauge 9 and the water outlet pump 10. Under the action of the water outlet pump 10, the treated wastewater in the inner shell 4 is guided out, and the water outlet pressure is monitored through the pressure gauge 9.

[0064] The application also provides a method for treating nitrogen-containing wastewater by using the sulfur autotrophic denitrification dynamic membrane bioreactor. The sulfur particles 3 and activated sludge are added into the nitrogen-containing wastewater in the reaction zone 12 of the sulfur autotrophic denitrification dynamic membrane bioreactor, mixed, and after the formation of the dynamic membrane, the nitrogen removal treatment is carried out.

[0065] The method specifically comprises the following steps:

[0066] Step 1. The sulfur particles 3 and activated sludge are added into the nitrogen-containing wastewater in the reaction zone 12, stirred and mixed to obtain the mixed wastewater to be treated.

[0067] The particle size of the sulfur particles is 20-200 μm, preferably 50-150 μm, and more preferably 50-100 μm.

[0068] In the mixed wastewater to be treated, the concentration of sulfur is 10-100 g / L, preferably 20-60 g / L, and more preferably 30-40 g / L; and the concentration of activated sludge is 0.1-10 g / L, preferably 0.5-2 g / L, and more preferably 0.8-1.2 g / L.

[0069] The stirring rate is 50-300 rpm, preferably 80-250 rpm, and more preferably 100-150 rpm.

[0070] Under the above concentration and stirring conditions, a more suitable dynamic membrane thickness can be obtained, thereby further reducing the turbidity of the effluent and improving the treatment effect.

[0071] Step 2. The mixed wastewater to be treated is passed through the membrane assembly 2 to obtain the dynamic membrane.

[0072] The influent pump 7 and the effluent pump 10 of the sulfur autotrophic denitrification dynamic membrane bioreactor are continuously operated, the effluent pipe 15 is connected to the influent pipe 14 to form an internal circulation. The suspended particles or colloidal particles formed by the sulfur particles and the activated sludge in the mixed wastewater to be treated gradually deposit on the filter membrane of the membrane assembly 2 to form a layer of dynamic membrane.

[0073] The membrane flux is 100-500 L / m 2 ·h, preferably 200-400 L / m 2 ·h, and more preferably 300-350 L / m 2 ·h. If the membrane flux is too large, the dynamic membrane is excessively compacted, and if the membrane flux is too small, the dynamic membrane is formed too slowly.

[0074] The dynamic membrane is completed when the turbidity of the effluent is less than 5 NTU.

[0075] Step 3. After the formation of the dynamic membrane, the mixed wastewater to be treated is treated.

[0076] After the dynamic membrane is formed, the membrane flux is 5-40 L / m 2 h, preferably 10-30 L / m 2 h, more preferably 10-20 L / m 2 h.

[0077] The sewage treatment temperature is 10-40°C, preferably 20-35°C, and more preferably 25-30°C. The above treatment temperature is the most suitable temperature for Thiobacillus denitrificans.

[0078] When the transmembrane pressure reaches 20-50 kPa, preferably 25-40 kPa, and more preferably 30-35 kPa, the dynamic membrane needs to be cleaned or replaced, and the nitrogen-containing wastewater treatment is completed.

[0079] After the treatment is completed, the effluent turbidity is less than 5 NTU.

[0080] In the present application, when the sulfur autotrophic denitrification dynamic membrane bioreactor is used to treat wastewater, not only a high nitrogen removal load is obtained, but also elemental sulfur is effectively intercepted. Compared with microfiltration / ultrafiltration membranes, the filtering material used in the present application is inexpensive. In-situ cleaning can be used to better remove the attached substances, so that frequent replacement of new membrane components can be avoided, and the operation and maintenance costs of the wastewater treatment process are significantly reduced.

[0081] Example

[0082] Example 1

[0083] The sulfur autotrophic denitrification dynamic membrane bioreactor is provided with a membrane assembly 2, an inner shell 4, an outer shell 5, a water bath area 6, a water inlet pump 7, a water level bottle 8, a pressure gauge 9, a water outlet pump 10, a stirrer 11, a reaction area 12, a water inlet bucket 13, a water inlet pipe 14, a water outlet pipe 15, and a constant-temperature water bath circulating tank 16. Specifically, as shown in Figure 1 .

[0084] In the sulfur autotrophic denitrification dynamic membrane bioreactor, the inner shell 4 has a diameter of 70 mm and a height of 140 mm. Sulfur powder is added to the reaction area 12, and the average particle size of the sulfur powder is about 100 μm. 120 ml of activated sludge mixed liquid is added. The prepared simulated nitrogen-containing wastewater is injected into the reactor, and the distance from the liquid surface to the bottom of the reactor is 70 mm. At this time, the sulfur concentration is 30 g / L, and the activated sludge concentration is about 1 g / L. The composition of the simulated wastewater is as follows: NO3 - -N content of 100 mg / L as nitrogen -1 , NH4 + -N content of 50 mg / L as nitrogen -1 , KH2PO4-P content of 5 mg / L as phosphorus -1 , NaHCO3 concentration of 1200 mg / L -1Na2S2O3 300 mg / L as S -1 .

[0085] The sulfur particles 3, activated sludge and simulated wastewater containing nitrogen were mixed well by the stirrer at a speed of 300 rpm, and then the membrane module 2 was placed in the reactor. The filter membrane was a nylon filter screen with a pore size of 25 μm. The size of the membrane module was 65 mm in length, 55 mm in width and 8 mm in thickness. The effective filtration area was 45 mm in length and 35 mm in width. The filter membrane was two pieces, and the total effective filtration area was 0.00315 m 2 ; the outlet of the reactor was connected to the inlet of the reactor by a peristaltic pump. The rotational speed of the pump was adjusted to achieve a membrane flux of 300 L / m 2 ·h. The system was operated in an internal circulation mode. The suspended particles or colloidal particles in the reaction zone 12 were deposited on the filtration material, indicating that a dynamic membrane was formed. When the turbidity of the effluent was less than 5 NTU, the dynamic membrane was formed. The photograph of the final dynamic membrane is shown in Figure 2 .

[0086] Example 2

[0087] The sulfur autotrophic denitrification dynamic membrane bioreactor in Example 1 was used. The inlet of the reactor was connected to the inlet peristaltic pump. The simulated wastewater was transported from the inlet to the reaction zone 12. The membrane module 2 with the dynamic membrane formed in Example 1 was installed at the middle position of the reaction zone 12. The outlet of the membrane module 2 was connected to the pressure gauge 9 through the outlet pipe 15. The treated water was pumped out by the outlet pump 10. The concentration of sulfur particles 3 in the reaction zone 12 was 30 g / L, and the concentration of activated sludge was 1 g / L. The mixture was continuously stirred by the stirrer at a speed of 150 rpm. The water level balancing device was used to maintain the liquid level at a distance of 70 mm from the bottom of the reactor. The membrane flux was 10-20 L / m 2 ·h. When the transmembrane pressure rose to 30 kPa, a period for cleaning or replacing the dynamic membrane ended. The composition of the original simulated wastewater was as follows: NO3 - -N (as nitrogen) 696 mg / L -1 , NH4 + -N (as nitrogen) 50 mg / L -1 , KH2PO4-P (as phosphorus) 5 mg / L -1 , NaHCO3 3 400 mg / L -1 .

[0088] Comparative Example

[0089] Comparative Example 1

[0090] Wastewater treatment was carried out in a manner similar to that of Example 2, except that the membrane module with the formed dynamic membrane was replaced with a polyvinylidene fluoride (PVDF) filter membrane with a pore size of 0.1 μm. The characteristics of the two membranes are shown in Table 1.

[0091] Table 1

[0092]

[0093] Experimental Example

[0094] Experimental Example 1

[0095] Select 100, 200, and 300 L / m respectively 2 The membrane flux was measured in h, and the time of dynamic membrane formation and effluent quality in Example 1 were tested. The results are as follows: Figure 3 and Figure 4 As shown.

[0096] from Figure 3 It can be seen that, under the selected membrane flux gradient, the transmembrane pressure of dynamic membrane filtration increases significantly with filtration time. Specifically, at 300 L / m... 2 During the formation of the dynamic membrane at a flux of ·h, the transmembrane pressure increased most significantly from 2.5 kPa to 24.7 kPa within 100 minutes. (200 L / m) 2 At a membrane flux of h, the transmembrane pressure increased from 2.5 kPa to 20.7 kPa within the same time period. (100 L / m) 2 At h-membrane flux, the transmembrane pressure increases relatively slowly, rising from 2.5 kPa to 16.1 kPa.

[0097] Figure 4 This demonstrates the change in effluent turbidity with filtration time during dynamic membrane formation at different membrane fluxes. The membrane flux is 300 L / m³. 2 At 1 hour, the turbidity of the filtered water from the dynamic membrane system decreased from 173.5 NTU to 4.8 NTU after approximately 55 minutes, and to 3.2 NTU after 100 minutes. This was achieved at a membrane flux of 200 L / m³. 2 At h, the turbidity of the filtered water from the dynamic membrane system decreased from 206 NTU to 4.78 NTU after approximately 75 minutes, and to 4.2 NTU after 100 minutes. This was achieved at a membrane flux of 100 L / m³. 2 At 1 hour, the turbidity of the filtered water from the dynamic membrane system decreased from 239.5 NTU to 5.05 NTU after about 95 minutes, and further to 4.82 NTU after 100 minutes. The rapid decrease in turbidity indicates the rapid formation of the dynamic membrane layer.

[0098] Overall, using 300L / m 2The time required for the dynamic membrane to form is relatively shorter, and the turbidity of the effluent is also significantly reduced.

[0099] Experimental Example 2

[0100] The clean nylon filter screen in Example 1 and the 300 L / m2 2 The dynamic membrane formed by the membrane flux of 0.5 L / (m2.h) was subjected to scanning electron microscope (SEM) test, and the results are shown in Figure 5

[0101] As can be seen from Figure 5 (a) and Figure 5 (b), the clean nylon filter screen has a large number of voids (about 25 μm) formed by regularly woven fibers. As can be seen from Figure 5 (c) and Figure 5 (d), a layer of denser membrane than the nylon filter screen is gradually formed on the surface of the nylon filter screen, which is loose in structure, covered by sulfur particles and microorganisms, and can effectively intercept the suspended particles or colloidal particles in the reactor and prevent the loss of sulfur particles. Detailed magnified observation of the surface of the dynamic membrane shows that there are small porous particle substances wrapped and entangled by other substances in the dynamic membrane layer, which are confirmed by element analysis to be elemental sulfur. It can be seen that this layer of dynamic membrane not only has the function of intercepting smaller particles, but also has the function of denitrification. Figure 5 Figure 6

[0102] Experimental Example 3

[0103] The particle size of the suspension in the reaction zone of Example 1 was analyzed by using a Mastersizer 3000 laser particle size analyzer (Malvern, UK) with a measurement range of 0.01 μm to 3500 μm, and the results are shown in Run period (d)

[0104] The median particle size is 25.7 μm, 95% of the particles are below 75 μm, and 50% of the particles are below 25 μm, which indicates that the dynamic membrane formed has a smaller pore size than the filter material, and can effectively intercept smaller particles in the reactor.

[0105] Experimental Example 4

[0106] The reaction zone of Example 1 and the 300 L / m2 2 ​​​​EPS measurement was carried out on the dynamic membrane formed by the membrane flux of 10, 20, 30 L / m

[0107] As can be seen from Table 2, the BEPS content of each substance in the dynamic membrane layer is lower than that in the reaction zone. The affinity between protein and sludge particles is higher than that between polysaccharide and sludge particles, and the protein / polysaccharide ratio of EPS in the dynamic membrane layer is 2.09, which is higher than that in the reaction zone (1.8). This indicates that the dynamic membrane layer enhances the adhesion of microorganisms on the membrane surface through the effect of EPS, making the dynamic membrane structure dense, so that the dynamic membrane layer can obtain effective filtration retention performance.

[0108] Table 2

[0109]

[0110] Experimental Example 5

[0111] The membrane flux of 10, 20, 30 L / m 2 The wastewater treatment efficiency of Example 2 was measured at the membrane flux of 10, 20, 30 L / m 2 The running period of the dynamic membrane at the membrane flux of 30 L / m 2 The running period of the dynamic membrane at the membrane flux of 10 L / m 2 The running period of the dynamic membrane at the membrane flux of 20 L / m

[0112] Table 3

[0113] Membrane flux (L / m 2 • h) Figure 7 10 15 20 12 30 9

[0114] Experimental Example 6

[0115] The membrane flux of 20 L / m 2 The transmembrane pressure and the turbidity of the effluent during the running period (the transmembrane pressure rising to 30 kPa is taken as a period for cleaning or replacing the dynamic membrane) of Example 2 and Comparative Example 1 were measured at the membrane flux of 20 L / m Figure 7 .

[0116] From ​ It can be seen that the trans-membrane pressure in Example 2 was maintained at 2.5 kPa for 0-9 days, and the increasing rate was increased for 9-12 days, and reached 30 kPa on the 12th day; the trans-membrane pressure in Comparative Example 1 was maintained at 2.5 kPa for 0-6 days, and the increasing rate was increased for 6-8 days, and reached 30 kPa on the 8th day. In addition, the turbidity of the effluent in Example 2 and Comparative Example 1 was maintained below 5 NTU. This shows that the dynamic membrane can not only effectively intercept the suspended particles or colloidal particles in the reactor, but also obtain a higher operation period.

[0117] Experimental Example 7

[0118] The membrane flux was 20 L / m 2 The effluent nitrate nitrogen concentration and effluent elemental sulfur concentration in Example 2 and Comparative Example 1 were determined in one cycle (taking the trans-membrane pressure rising to 30 kPa as one cycle of the dynamic membrane needing cleaning or replacement). The results are shown in Table 4.

[0119] Table 4

[0120]

[0121] As can be seen from Table 4, the use of the sulfur autotrophic denitrification dynamic membrane reactor described in Example 2 of the present application for wastewater denitrification can greatly reduce the effluent nitrate nitrogen concentration. Through the total nitrogen removal load formula, the total nitrogen removal load of Example 2 is 2.7 kg·N / (m3·d), the effluent elemental sulfur concentration is less than 1 mg / L, and the interception rate is 98.33%, which is comparable to the comparative example. This shows that the use of the sulfur autotrophic denitrification dynamic membrane reactor of the present application for wastewater denitrification can obtain good effluent water quality.

[0122] The above detailed description of the present application is combined with the specific embodiments and / or exemplary examples and the accompanying drawings, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that the technical solutions and embodiments of the present application can be variously replaced, modified or improved without departing from the spirit and scope of the present application, and these all fall within the scope of the present application. The scope of protection of the present application is subject to the appended claims.

Claims

1. A method for treating nitrogen-containing wastewater using a sulfur autotrophic denitrification dynamic membrane bioreactor, characterized by, The sulfur autotrophic denitrification dynamic membrane bioreactor is provided with a reaction zone (12), and the mixed nitrogen-containing wastewater mixed with sulfur particles (3) and activated sludge is led out after passing through the membrane assembly (2) in the reaction zone (12) to form a dynamic membrane, and the nitrogen-containing wastewater is subjected to denitrification treatment, The membrane assembly (2) comprises a filter membrane and a filter membrane support frame, The filter membrane has a pore size of 1-150 μm, The sulfur autotrophic denitrification dynamic membrane bioreactor further comprises an inner shell (4), an outer shell (5), a water inlet pipe (14) and a water outlet pipe (15), The inner shell (4) is provided with the membrane assembly (2) inside to form the reaction zone (12), The water inlet pipe (14) is arranged at the lower part of the outer shell (5) and is communicated with the reaction zone (12) inside the inner shell (4); the water outlet pipe (15) is arranged at the top of the outer shell (5) and is communicated with the water outlet of the membrane assembly (2) of the reaction zone (12) inside the inner shell (4), A stirrer (11) is arranged in the middle of the inner shell (4), and the sulfur autotrophic denitrification dynamic membrane bioreactor is further provided with a balance water level bottle (8), the water inlet end of the balance water level bottle (8) is communicated with a water inlet bucket (13) through a water inlet pump (7), and the nitrogen-containing wastewater in the water inlet bucket (13) is led into the balance water level bottle (8) under the action of the water inlet pump (7) and then into the water inlet pipe (14); The method specifically comprises the following steps: Step 1. The sulfur particles (3) and activated sludge are added into the nitrogen-containing wastewater in the reaction zone, and the mixture is stirred to obtain the mixed wastewater to be treated; Step 2. The mixed wastewater to be treated is passed through the membrane assembly to obtain a dynamic membrane; Step 3. After the dynamic membrane is formed, the mixed wastewater to be treated is treated, In step 1, The particle size of the sulfur particles is 20-200 μm; The concentration of sulfur in the mixed wastewater to be treated is 10-100 g / L; The concentration of activated sludge is 0.1-10 g / L, In step 2, Membrane flux is 100-500 L / m 2. h, When the turbidity of the effluent is less than 5 NTU, the dynamic membrane is completed.

2. The method according to claim 1, characterized in that, The balance water level bottle (8) is further provided with a balance pipe (801) and a gas guide pipe (802), the balance pipe (801) is arranged at a height higher than the water inlet end of the balance water level bottle (8), and the gas guide pipe (802) is arranged at the top of the balance water level bottle (8) to keep the inside of the balance water level bottle (8) communicated with the outside; The water outlet of the balance water level bottle (8) communicated with the water inlet pipe (14) is arranged at a height between the height of the balance pipe (801) and the height of the water inlet end of the balance water level bottle (8).

3. The method of claim 1, wherein, The filter membrane has a pore size of 20-75 μm.

4. The method of claim 3, wherein, The filter membrane has a pore size of 20-50 μm.

5. The method of claim 1, wherein, The water outlet pipe (15) is connected with a pressure gauge (9) and a water outlet pump (10).

6. The method of claim 1, wherein, In step 1, The particle size of the sulfur particles is 50-150 μm; The concentration of sulfur in the mixed wastewater to be treated is 20-60 g / L; The concentration of activated sludge is 0.5-2 g / L.

7. The method of claim 6, wherein, In step 1, The particle size of the sulfur particles is 50-100 μm; The concentration of sulfur in the mixed wastewater to be treated is 30-40 g / L; The concentration of activated sludge is 0.8-1.2 g / L.

8. The method of claim 1, wherein, In step 2, The membrane flux is 200-400 L / m 2. h.

9. The method of claim 8, wherein, In step 2, the membrane flux is 300-350 L / m 2. h.

10. The method of claim 7, wherein, In step 3, after the dynamic membrane is formed, the membrane flux is 5-40 L / m 2 • h, When the transmembrane pressure reaches 20-50 kPa, the nitrogen-containing wastewater treatment is completed, The sewage treatment temperature is 10-40℃. After the treatment, the turbidity of the effluent is less than 5 NTU.

11. The method of claim 10, wherein, In step 3, after the dynamic membrane is formed, the membrane flux is 10-30 L / m 2 • h, When the transmembrane pressure reaches 25-40 kPa, the nitrogen-containing wastewater treatment is completed, The sewage treatment temperature is 20-35℃.

12. The method of claim 11, wherein, In step 3, after the dynamic membrane is formed, the membrane flux is 10-20 L / m 2 • h, When the transmembrane pressure reaches 30-35 kPa, the nitrogen-containing wastewater treatment is completed, The sewage treatment temperature is 25-30℃.

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