A method for rapid cultivation and enrichment of sulfur disproportionating functional bacteria and its application

Abstract

The present invention discloses a method for rapidly culturing and enriching sulfur disproportionation functional bacteria, comprising a sulfur biofilter, wherein a solution containing NO3 with a pH of 7 to 9 is input into the filter. ‑ -N wastewater, adjusting the wastewater empty bed residence time (EBCT) is 0.5~1.5h, after denitrification is run to the sulfur autotrophic denitrification biofilter and started, tap water with an alkalinity of 500~800mg / L is input into the filter through the water inlet pipe, and EBCT is 2~2.5h, and sulfur disproportionation is run to the sulfur disproportionation biofilter and started, and continues to run for 8~10 days. The present invention is carried out functional conversion by the sulfur autotrophic denitrification biofilter that is successfully started and smoothly operated, and the enrichment culture of sulfur disproportionation functional bacteria group is carried out on the basis of having successfully enriched denitrification functional microorganisms. By the function switching method of the present invention, the enrichment time of sulfur disproportionation functional microorganisms is greatly shortened, the rate of sulfur disproportionation reaction and the output of biological sulfide are improved, and the problem of slow growth and enrichment of sulfur disproportionation microorganisms is solved.

Description

Technical Field

[0001] The present invention relates to the field of wastewater treatment, in particular to a method for rapidly enriching sulfur disproportionating functional bacteria in a sulfur autotrophic denitrification system and an application thereof. Background Art

[0002] Eutrophication of water bodies can trigger harmful algae outbreaks such as red tides and algal blooms, leading to a host of problems that seriously impact water quality and ecological safety. Nitrogen and phosphorus pollutants are key drivers of these water environmental issues and serve as key indicators of water nutrient levels. In recent years, with the introduction of a series of water environment governance policies, environmental protection authorities have imposed higher discharge limits on sewage treatment plants. Therefore, in addition to existing secondary biochemical treatment at sewage treatment plants, deep denitrification and phosphorus removal is essential to meet the increased pollutant emission standards.

[0003] Sulfur autotrophic denitrification process is a widely used denitrification technology that uses reduced sulfur (S 0 、S 2- 、S2O3 2- ) as an electron donor, using autotrophic denitrifying bacteria to remove nitrogen, no external carbon source is required, no carbon emissions are generated, and the cost of removing the same amount of nitric nitrogen electron donor is low, which has a high advantage. In the sulfur autotrophic denitrification process, the technology of using sulfur particles as electron donors is more common. Compared with other reduced sulfur, sulfur particles are solid and can serve as the basis for microbial growth and electron donors at the same time. The sulfur autotrophic denitrification filter process with sulfur particles as filler has a simple operation mode and high denitrification efficiency.

[0004] Sulfide (S 2- ) has a higher water solubility than elemental sulfur and can participate in the sulfur autotrophic denitrification reaction, generating more electrons. It is often added to sulfur autotrophic denitrification systems as an exogenous electron donor to improve denitrification efficiency. Sulfide, as a transfer carrier for dissolved elemental sulfur in water, can promote the formation of polysulfide polymers in water and increase the efficiency of elemental sulfur utilization by organisms. The addition of sulfide can enhance the efficiency of electron transfer between elemental sulfur and sulfur-oxidizing bacteria, improving the denitrification capacity of the denitrification system.

[0005] Elemental sulfur biodisproportionation is the process by which autotrophic microorganisms use elemental sulfur as both an electron donor and an electron acceptor to produce sulfide and sulfate. This reaction requires the absence of dissolved oxygen, nitrates, and other highly oxidizing substances in the water, and a neutral or alkaline pH. Adding the generated sulfide to the sulfur autotrophic denitrification system through the biological sulfur disproportionation reaction not only saves costs but also allows for the control of sulfide production by regulating the biological sulfur disproportionation process, thereby avoiding secondary sulfide pollution.

[0006] Currently, the widely used sulfur autotrophic denitrification technology often uses elemental sulfur particles as a filler material to provide an electron donor in the sulfur autotrophic denitrification reaction. However, the low solubility of elemental sulfur in water results in low efficiency of elemental sulfur utilization by microorganisms, hindering the improvement of the denitrification efficiency of elemental sulfur autotrophic denitrification technology. Sulfide chemicals are expensive and difficult to store, and directly adding sulfide to the denitrification system will increase costs. Furthermore, the process of adding sulfide to the denitrification system also carries the risk of secondary pollution caused by excessive addition of sulfide.

[0007] Furthermore, the slow growth rate of sulfur dismutation microorganisms and the lack of relevant research limit the rate of enrichment and cultivation of sulfur dismutation-functional microorganisms. The enrichment rate of sulfur dismutation-functional microorganisms affects the yield of sulfide generated by the sulfur dismutation reaction, thereby affecting the denitrification efficiency and widespread application of sulfur autotrophic denitrification technology. Summary of the Invention

[0008] In order to solve the above-mentioned technical problems, the present invention provides a method for rapidly culturing and enriching sulfur disproportionating functional bacteria.

[0009] Another object of the present invention is to treat wastewater by using a sulfur biofilter after rapid cultivation and enrichment of sulfur disproportionating functional bacteria.

[0010] The technical solution adopted by the present invention is: a method for rapidly culturing and enriching sulfur disproportionating functional bacteria, including an elemental sulfur biofilter, and the method comprises the following steps:

[0011] 1) Sulfur autotrophic denitrification biofilter start-up: input NO3 with pH 7-9 into the filter through the water inlet pipe. - For wastewater containing -N, the flow rate of water inlet pump I is adjusted to an empty bed residence time (EBCT) of 0.5-1.5 hours for denitrification operation. Backwashing is performed once a day during operation. This backwashing involves feeding the effluent from the effluent area into the filter through a backwash pipe for 5-10 minutes. During denitrification operation, the total nitrogen value of the effluent from the biological filter is tested. Once the total nitrogen value reaches a certain value, the sulfur autotrophic denitrification biological filter is activated. The biological filter activates sulfur autotrophic denitrification through self-enrichment, i.e., without the addition of additional inoculum.

[0012] 2) Start-up of sulfur disproportionation biofilter: After the sulfur autotrophic denitrification biofilter is started, tap water is input into the filter through the water inlet pipe, and the flow rate of the water inlet pump I is adjusted to the empty bed residence time (EBCT) of the tap water is 2 to 2.5 hours, and sulfur disproportionation operation is carried out. During the sulfur disproportionation operation, the effluent sulfide S in the effluent area of ​​the biofilter is detected. 2- Concentration, when the effluent sulfide S 2- When the concentration reaches a certain value, the sulfur disproportionation biofilter starts; no backwashing is performed during the sulfur disproportionation operation.

[0013] 3) Continue to operate for 8 to 10 days to complete the enrichment of sulfur disproportionation functional bacteria.

[0014] Furthermore, the structure of the elemental sulfur biological filter is that, from bottom to top, the filter comprises a water distribution layer, a supporting layer, a reaction layer and a water outlet area; the water inlet pipe is connected to the water distribution layer through a valve and a water inlet pump I; the backwash pipe is connected to the water distribution layer through a valve and a water inlet pump II.

[0015] Furthermore, the reaction layer is filled with elemental sulfur particles with a particle size of 2 to 6 mm.

[0016] Furthermore, in step 1), the total nitrogen value of the effluent from the effluent area of ​​the biological filter is detected. When the denitrification load of the biological filter reaches 0.5-0.8 kg NO3 - -N·m -3 ·d -1 , and maintain a stable state for 2 to 3 days, the sulfur autotrophic denitrification biological filter is started.

[0017] Furthermore, in step 1), backwashing is performed once a day, and the backwashing flow rate is controlled to prevent the reaction layer from becoming hardened.

[0018] Furthermore, in step 2), the tap water is tap water whose alkalinity is adjusted to 500-800 mg / L using sodium bicarbonate. The alkalinity refers to the amount of alkaline salt dissolved in the water, i.e., the amount of alkaline salt that can react with H + The amount of the reacting substance.

[0019] Furthermore, in step 2), the effluent sulfide S in the effluent area of ​​the biofilter is detected. 2- When the effluent sulfide S 2- When the concentration reaches 3-5 mg / L, the sulfur disproportionation biological filter starts.

[0020] The invention provides an application of an elemental sulfur biofilter obtained by the method for rapidly culturing and enriching sulfur disproportionating functional bacteria in treating wastewater.

[0021] The beneficial effects of the present invention are:

[0022] 1. The method of the present invention is to convert the function of the sulfur autotrophic denitrification biofilter that has been successfully started and smoothly operated, that is, to artificially adjust the water quality of the sulfur autotrophic denitrification biofilter inlet to control the NO3 - -N content causes the biofilter to start sulfur disproportionation reaction, and the sulfur disproportionation functional bacteria are enriched and cultured on the basis of the successful enrichment of denitrification functional microorganisms. Compared with the biofilter with sulfur disproportionation function directly activated, the function switching method of the present invention greatly shortens the enrichment time of sulfur disproportionation functional microorganisms, improves the rate of sulfur disproportionation reaction and biological sulfide S 2-The yield is high, which solves the problem of slow growth and enrichment of sulfur disproportionation microorganisms.

[0023] 2. The method of the present invention improves the efficiency of enriching sulfur disproportionation-functional microorganisms. Directly culturing sulfur disproportionation-functional microorganisms requires about 35 days for the reaction system to begin to undergo biological sulfur disproportionation. However, using the method of the present invention, the reaction system can achieve sulfur disproportionation and undergo biological sulfur disproportionation reaction within 2 hours of functional conversion.

[0024] 3. The method of the present invention improves the efficiency of biological sulfur disproportionation and enables the reaction system to generate more biological sulfide S 2- Directly cultivate and enrich sulfur disproportionation functional microorganisms. When the enrichment reaches about 45 days, the biological sulfide S in the effluent of the reaction system 2- The concentration is about 1.5 mg / L, and the effluent of the reaction system can provide 70 mg / L of biological sulfide S after 10 days of functional conversion using the method of the present invention. 2- , used to participate in sulfur autotrophic denitrification reaction to improve denitrification efficiency.

[0025] 4. The sulfide generated by the method of the present invention has a significant effect on the denitrification capacity of sulfur autotrophic denitrification. Adding the product of this method to a sulfur autotrophic denitrification biological filter can increase its denitrification efficiency to 12.8-46.1%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of the elemental sulfur biofilter.

[0027] Figure 2 This is a comparison chart of the nitrate and nitrogen removal capacity of the sulfur autotrophic denitrification filter before and after adding the effluent of the sulfur disproportionation biological filter.

[0028] Figure 3 This is a comparison chart of sulfide production in the sulfur disproportionation biological filter before and after the method of the present application is adopted. DETAILED DESCRIPTION

[0029] Example 1

[0030] (1) Structure of elemental sulfur biofilter (10)

[0031] The elemental sulfur biological filter (10) comprises a filter (11).

[0032] The filter tank (11) is provided with a water distribution layer (12), a supporting layer (13), a reaction layer (14) and a water outlet area (15) from bottom to top. The water inlet pipe (16) is connected to the water distribution layer (12) through a valve and a water inlet pump I (17); the backwash pipe (18) is connected to the water distribution layer (12) through a valve and a water inlet pump II (19).

[0033] Preferably, in this embodiment, the reaction layer (14) is filled with elemental sulfur particles with a particle size of 2 to 6 mm.

[0034] (2) Rapid culture and enrichment method of sulfur disproportionation functional bacteria

[0035] Using an elemental sulfur biofilter (10), the method comprises the following steps:

[0036] 1) Sulfur autotrophic denitrification biofilter startup: input NO3 containing water with a pH of 7 to 9 into the filter (11) through the water inlet pipe (16). - -N wastewater, adjust the flow rate of the water inlet pump I (17) to the empty bed residence time (EBCT) of the wastewater to 0.5-1.5h, and perform denitrification operation. During the operation, backwashing is performed once a day. The backwashing is to input the effluent of the effluent area into the filter tank (11) through the backwash pipe (18). The backwashing time is 5-10min. During the denitrification operation, the total nitrogen value of the effluent of the effluent area (15) of the biological filter is continuously detected. When the total nitrogen value reaches a certain value, the sulfur autotrophic denitrification biological filter is started.

[0037] Preferably, in this embodiment, backwashing is performed once a day, and the backwashing flow rate is controlled to prevent the reaction layer from becoming hardened.

[0038] As a preferred embodiment, in this embodiment, the total nitrogen value of the effluent from the effluent area (15) of the biological filter is detected once every hour. When the denitrification load of the biological filter reaches 0.5-0.8 kg NO3 - -N·m -3 ·d -1 , and maintain a stable state for 2 to 3 days, the sulfur autotrophic denitrification biological filter is started.

[0039] 2) Start-up of sulfur disproportionation biofilter: After the sulfur autotrophic denitrification biofilter is started, tap water is input into the filter (11) through the water inlet pipe (16), and the flow rate of the water inlet pump I (17) is adjusted to the empty bed residence time (EBCT) of the tap water is 2 to 2.5 hours, and sulfur disproportionation operation is carried out. During the sulfur disproportionation operation, the effluent sulfide S in the effluent area (15) of the biofilter is detected. 2- Concentration, when the effluent sulfide S 2- When the concentration reaches a certain value, the sulfur disproportionation biofilter starts; no backwashing is performed during the sulfur disproportionation operation.

[0040] Preferably, in this embodiment, the tap water is tap water whose alkalinity is adjusted to 500-800 mg / L using sodium bicarbonate.

[0041] As a preference, in this embodiment, the sulfide S in the effluent area (15) of the biological filter is detected every hour. 2- When the effluent sulfide S 2-When the concentration reaches 3-5 mg / L, the sulfur disproportionation biological filter starts.

[0042] 3) Continue to operate for 8 to 10 days to complete the enrichment of sulfur disproportionation functional bacteria.

[0043] (3) Effect

[0044] Adding the sulfur disproportionation biofilter product to the sulfur autotrophic denitrification biofilter, that is, mixing the sulfur disproportionation filter effluent with the sulfur autotrophic denitrification biofilter influent, can improve the denitrification efficiency of the denitrification biofilter ( Figure 2 As shown). NO3 in the influent of sulfur autotrophic denitrification biofilter - -N concentration is 25-30 mg / L, and NO3 in the effluent of the sulfur autotrophic denitrification biofilter is not added to the effluent of the sulfur disproportionation filter. - -N concentration is about 10~13mg / L, NO3 - -N removal rate is about 56-60%. The sulfur disproportionation biofilter effluent after the sulfur disproportionation microorganisms are rapidly enriched by the method of this application is added to the influent NO3 - -N content remains unchanged, the sulfur disproportionation filter effluent after adding sulfur autotrophic denitrification biological filter effluent NO3 - -N concentration is 5.5~8mg / L, nitrate nitrogen removal rate is 73~78%, and the total nitrogen concentration of the effluent meets the sewage treatment plant's total nitrogen direct discharge concentration of less than 10mg / L (DB11 / 307-2013, etc.) discharge regulations.

[0045] Previous studies and related reports did not mention the specific enrichment methods of sulfur disproportionation functional microorganisms, such as Figure 3 As shown, the present application is based on a method for rapid enrichment of denitrifying functional microorganisms in a biofilter process, that is, the denitrifying functional microorganisms are enriched in a sulfur disproportionation biofilter by self-enrichment without adding additional inoculum. Under the cultivation method, a trace amount of sulfide S was detected in the effluent of the sulfur disproportionation biofilter around the 28th day of operation. 2- The concentration is about 0.5 mg / L. After running for about 35 days, the effluent from the sulfur disproportionation filter contains about 1 mg / L of sulfide S. 2-At this time, the relative abundance of sulfur disproportionation functional microorganisms such as Desulfobulbus, Desulfocapsa and Desulfomonile in the sulfur disproportionation biological filter is relatively low. Through the rapid enrichment and cultivation method of sulfur disproportionation functional microorganisms in the present invention, that is, in a successfully started and smoothly operating sulfur autotrophic denitrification biological filter, by artificially adjusting the influent alkalinity, residence time and other conditions, the sulfur disproportionation microorganisms in the sulfur disproportionation biological filter are enriched. This method can quickly enrich sulfur disproportionation functional microorganisms such as Desulfobulbus, Desulfocapsa and Desulfomonile, thereby increasing sulfide S 2- The amount of sulfide generated by the rapid method of the present invention is enriched, and the sulfide S in the effluent of the sulfur disproportionation biofilter is 100% on the first day after startup. 2- It is about 7 mg / L, and it is showing an increasing trend. On the 12th day of operation, the sulfide content of the effluent from the sulfur disproportionation biofilter is S 2- The concentration of sulfide S in the effluent of the sulfur disproportionation biofilter was basically stable at about 70 mg / L, and a large number of sulfur disproportionation functional microorganisms such as Desulfobulbus, Desulfocapsa and Desulfomonile were enriched. Compared with the sulfide S in the effluent of the sulfur disproportionation biofilter before the enrichment method of the present application, the concentration of sulfide S in the effluent of the sulfur disproportionation biofilter was significantly higher than that in the previous step. 2- The production volume increased by 70 times, while the enrichment and cultivation time of sulfur disproportionation functional microorganisms was greatly shortened.

Claims

1. A method for rapidly culturing and enriching sulfur disproportionating functional bacteria, comprising a sulfur biofilter (10), characterized in that: The method comprises the following steps: 1) Sulfur autotrophic denitrification biofilter startup: Input NO3 containing water with a pH of 7 to 9 into the filter (11) of the elemental sulfur biofilter (10) through the water inlet pipe (16). – -N wastewater, adjust the flow rate of the water inlet pump I (17) to the empty bed residence time of the wastewater to 0.5 to 1.5 hours, and perform denitrification operation. During the operation, backwashing is performed once a day. The backwashing is performed by inputting the effluent of the effluent area (15) into the filter tank (11) through the backwash pipe (18). The backwashing time is 5 to 10 minutes. During the denitrification operation, the total nitrogen value of the effluent of the effluent area (15) of the biological filter is detected. When the total nitrogen value reaches a certain value, the sulfur autotrophic denitrification biological filter is started; 2) Start-up of sulfur disproportionation biofilter: After the sulfur autotrophic denitrification biofilter is started, tap water with alkalinity adjusted to 500-800 mg / L with sodium bicarbonate is input into the filter (11) through the water inlet pipe (16). The flow rate of the water inlet pump I (17) is adjusted to an empty bed residence time of 2-2.5 hours for the tap water to start sulfur disproportionation operation. During the sulfur disproportionation operation, the effluent sulfide S in the effluent area (15) of the biofilter is detected. 2- Concentration, when the effluent sulfide S 2- When the concentration reaches a certain value, the sulfur disproportionation biofilter starts; 3) Continue operation for 8 to 10 days to complete the enrichment of sulfur disproportionation functional bacteria.

2. The method for rapid cultivation and enrichment of sulfur disproportionation functional bacteria according to claim 1, characterized in that: The structure of the elemental sulfur biofilter (10) is that the filter (11) comprises a water distribution layer (12), a supporting layer (13), a reaction layer (14) and a water outlet area (15) from bottom to top, the water inlet pipe (16) is connected to the water distribution layer (12) through a valve and a water inlet pump I (17); and the backwash pipe (18) is connected to the water distribution layer (12) through a valve and a water inlet pump II (19).

3. The method for rapid cultivation and enrichment of sulfur disproportionation functional bacteria according to claim 2, characterized in that: The reaction layer (14) is filled with elemental sulfur particles with a particle size of 2 to 6 mm.

4. The method for rapid cultivation and enrichment of sulfur disproportionation functional bacteria according to claim 1, characterized in that: In step 1), the total nitrogen value of the effluent from the effluent area (15) of the biofilter is detected. When the denitrification load of the biofilter reaches 0.5-0.8 kgNO3 - -N·m -3 ·d -1 When the sulfur autotrophic denitrification biological filter is started.

5. The method for rapid cultivation and enrichment of sulfur disproportionation functional bacteria according to claim 1, characterized in that: In step 1), backwashing is performed once a day, and the backwashing flow rate is controlled to prevent the reaction layer (14) from becoming hardened.

6. The method for rapid cultivation and enrichment of sulfur disproportionation functional bacteria according to claim 1, characterized in that: In step 2), the effluent sulfide S in the effluent area (15) of the biofilter is detected. 2- When the effluent sulfide S 2- When the concentration reaches 3-5 mg / L, the sulfur disproportionation biological filter starts.

7. Use of an elemental sulfur biofilter obtained by the method for rapid cultivation and enrichment of sulfur disproportionating functional bacteria according to any one of claims 1 to 6 in treating wastewater.

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