Quick starting method of degradable carrier autotrophic denitrification biofilter process

Abstract

The invention belongs to the technical field of sewage treatment, and discloses a quick starting method of a degradable carrier autotrophic denitrification biological filter process. The method comprises the following steps: continuously feeding water into the autotrophic denitrification biological filter filled with the degradable carrier microbial film autotrophic nitrogen removal filler, and adding an accelerant A into the filter; when a first culture condition threshold value is reached, adding an accelerant B; and when a second culture condition threshold value is reached, adding an accelerant C, and when a third culture condition threshold value is reached, successfully starting the process, entering a stable operation stage, and stopping adding the accelerant C. The starting time of the degradable carrier autotrophic denitrification biofilter is shortened, the starting rate of the biofilter is increased, and the purpose of quick starting is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and more specifically, relates to a rapid start-up method for a biodegradable carrier autotrophic denitrification biofilter process. Background Art

[0002] At present, sewage discharge in most areas complies with the Class A discharge standard in the Pollutant Discharge Standard for Urban Sewage Plants (GB18918-2002), where the total nitrogen (TN) concentration does not exceed 15 mg / L. Some areas implement local standards, and the total nitrogen concentration is required to be no more than 10 mg / L. In the sewage treatment process, denitrification biological denitrification filters are usually used to deeply remove nitrate nitrogen from the water.

[0003] The principle of biological denitrification is that microorganisms use nitrate or nitrite in water as electron acceptors and organic matter, hydrogen, sulfur or sulfur-containing compounds as electron donors to reduce nitrate or nitrite to nitrogen gas through microbial metabolism under anaerobic conditions. Biological denitrification can be divided into heterotrophic denitrification and autotrophic denitrification according to the growth characteristics of microorganisms. The corresponding processes are heterotrophic denitrification biofilter and autotrophic denitrification biofilter.

[0004] Heterotrophic denitrification biofilters operate stably and have a fast reaction rate, but they require continuous addition of organic carbon sources during operation, which can lead to problems such as high sludge production, high backwashing frequency, and fluctuations in effluent chemical oxygen demand (COD), increasing water treatment costs.

[0005] In the autotrophic denitrification biofilter, the obligate inorganic chemoautotrophic Thiobacillus species uses thiosulfate, elemental sulfur, sulfide, etc. as electron donors and nitrate nitrogen as electron acceptor under anaerobic or anoxic conditions to reduce nitrate nitrogen to nitrogen gas and oxidize sulfur to sulfate, completing the autotrophic denitrification process. Compared with heterotrophic denitrification, autotrophic denitrification does not require an external carbon source, has less sludge production, low backwashing frequency, and lower operating costs. However, autotrophic denitrification microorganisms grow slowly, making it difficult to quickly form a stable microbial film and quickly carry out denitrification biological denitrification, which limits the use of autotrophic denitrification biological denitrification.

[0006] Therefore, it is urgent to propose a rapid start-up method for the autotrophic denitrification biofilter process with a degradable carrier. Summary of the invention

[0007] The purpose of the present invention is to solve the problem of slow startup speed of autotrophic denitrification biofilter with degradable carrier, and to propose a rapid startup method of autotrophic denitrification biofilter with degradable carrier. The present invention reduces the startup time of autotrophic denitrification biofilter with degradable carrier, improves the startup rate of the filter, and achieves the purpose of rapid startup.

[0008] In order to achieve the above object, the present invention provides a rapid start-up method for a biodegradable carrier autotrophic denitrification biofilter process, the method comprising the following steps:

[0009] S1: The first training stage

[0010] Continuously feeding water into an autotrophic denitrification biofilter filled with a degradable carrier microbial membrane autotrophic denitrification filler; adding a denitrifying Thiobacillus growth promoter A to the autotrophic denitrification biofilter, monitoring the dissolved oxygen concentration and redox potential of the water in the autotrophic denitrification biofilter; and entering the next culture stage when the dissolved oxygen concentration and redox potential of the water in the autotrophic denitrification biofilter reach a first culture condition threshold;

[0011] S2: Second training stage

[0012] During the continuous water inflow process, a growth promoter B of Thiobacillus denitrificans is added to the autotrophic denitrification biofilter, and the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent from the autotrophic denitrification biofilter are monitored; when the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent from the autotrophic denitrification biofilter reach the second culture condition threshold, the next culture stage is entered;

[0013] S3: The third training stage

[0014] During the continuous water inflow process, a denitrifying Thiobacillus growth promoter C is added to the autotrophic denitrifying biological filter, and the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent from the autotrophic denitrifying biological filter are monitored; when the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent from the autotrophic denitrifying biological filter reach the third culture condition threshold, it indicates that the process has been successfully started and entered a stable operation stage, and the addition of the denitrifying Thiobacillus growth promoter C is stopped.

[0015] According to the present invention, preferably, the inlet water temperature of the autotrophic denitrification biological filter is 10-38°C.

[0016] According to the present invention, preferably, the influent of the autotrophic denitrification biological filter includes but is not limited to at least one of domestic sewage, industrial wastewater, secondary effluent from a sewage plant, total return water from a reclaimed water plant and landscape water.

[0017] According to the present invention, preferably, the autotrophic denitrification biological filter is an upflow or downflow biological filter.

[0018] According to the present invention, preferably, the denitrifying Thiobacillus growth promoter A comprises sodium thiosulfate, ammonium chloride, magnesium sulfate and ferrous sulfate.

[0019] According to the present invention, preferably, the denitrifying Thiobacillus growth promoter B comprises ammonium chloride, magnesium sulfate, ferrous sulfate and sodium bicarbonate.

[0020] According to the present invention, preferably, the Thiobacillus denitrificans growth promoter C comprises sodium bicarbonate and ammonium chloride.

[0021] According to the present invention, preferably, the volume ratio of the added amount of the denitrifying Thiobacillus growth promoter A to the amount of water in the autotrophic denitrifying biological filter is (0.8-1.2):1000.

[0022] According to the present invention, preferably, the first culture condition thresholds include: a dissolved oxygen concentration of less than 0.5 mg / L, and a redox potential of less than -150 mv.

[0023] According to the present invention, preferably, the first culture stage takes 10-18 hours.

[0024] According to the present invention, preferably, in the second culture stage, the volume ratio of the added amount of Thiobacillus denitrificans growth promoter B to the amount of water in the autotrophic denitrifying biological filter is (0.5-1.0):10000.

[0025] According to the present invention, preferably, the second culture condition threshold value includes: dissolved oxygen concentration is lower than 0.5 mg / L, redox potential is lower than -150 mv, and nitrate nitrogen removal rate is ≥90%.

[0026] According to the present invention, preferably, the second culture stage takes 16 to 49 hours.

[0027] According to the present invention, preferably, in the third culture stage, the volume ratio of the added amount of Thiobacillus denitrificans growth promoter C to the amount of water in the autotrophic denitrifying biological filter is (0.8-1.2):10000.

[0028] According to the present invention, preferably, the third culture condition threshold value includes: dissolved oxygen concentration is lower than 0.5 mg / L; redox potential is lower than -140 mv; nitrate nitrogen removal rate is ≥90%.

[0029] According to the present invention, preferably, the third culture stage takes 12-40 hours.

[0030] In the present invention, the dosage of each component in the denitrifying Thiobacillus growth promoter A, B and C is determined according to the quality of the treated water.

[0031] In the present invention, the denitrifying Thiobacillus growth promoter B is added in the second culture stage to accelerate the formation of denitrifying Thiobacillus microbial film on the surface of the filler.

[0032] In the present invention, the denitrifying Thiobacillus growth promoter C is added in the third culture stage to promote the stable growth of the denitrifying Thiobacillus microbial film on the surface of the filler.

[0033] The beneficial effects of the technical solution of the present invention are as follows:

[0034] The invention reduces the start-up time of the autotrophic denitrification biological filter tank with a degradable carrier, increases the start-up rate of the filter tank, and achieves the purpose of rapid start-up.

[0035] The method of the present invention can realize the rapid start-up of the autotrophic denitrification biological filter without inoculating activated sludge, and the fastest start-up time of the autotrophic denitrification biological filter of the method of the present invention can reach within 96 hours.

[0036] The sodium thiosulfate in the denitrifying Thiobacillus growth promoter A added in the early stage of the method of the present invention can play the role of an oxygen scavenger, reduce the influence of dissolved oxygen on the early growth of denitrifying Thiobacillus, and also can serve as a sulfur source required for the growth of denitrifying Thiobacillus to accelerate the growth of sulfur autotrophic denitrifying bacteria.

[0037] The method of the invention combines denitrifying Thiobacillus growth promoter A, denitrifying Thiobacillus growth promoter B and denitrifying Thiobacillus growth promoter C, and is suitable for different growth stages of denitrifying Thiobacillus.

[0038] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] 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 with reference to the accompanying drawings.

[0040] Figure 1 The figure shows the nitrate nitrogen removal rate of the rapid start-up method of the biodegradable carrier autotrophic denitrification biofilter process provided in Example 1 of the present invention within 15 days of stable operation after startup. DETAILED DESCRIPTION

[0041] 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.

[0042] In the following embodiments:

[0043] The degradable carrier microbial membrane autotrophic denitrification filler was purchased from Beijing Beipai Technology Co., Ltd.

[0044] Example 1

[0045] This embodiment provides a rapid start-up method for a biodegradable carrier autotrophic denitrification biofilter process, wherein the autotrophic denitrification biofilter is an upflow biofilter, the inlet water of the autotrophic denitrification biofilter is the secondary effluent of a sewage treatment plant, and the water quality conditions are: nitrate nitrogen 7-17 mg / L, chemical oxygen demand 15-30 mg / L, total nitrogen 8-18 mg / L, total phosphorus <0.3 mg / L, pH 6.8-7.1, and the filter design filtration rate is 3 m / h;

[0046] The method comprises the following steps:

[0047] S1: The first training stage

[0048] The autotrophic denitrification biofilter is filled with a degradable carrier microbial membrane autotrophic denitrification filler (thickness 2.5m, the supporting layer supporting the degradable carrier microbial membrane autotrophic denitrification filler in the autotrophic denitrification biofilter is a graded pebble layer, and the thickness of the graded pebble layer is 0.5m); water is continuously introduced into the autotrophic denitrification biofilter, and a denitrifying Thiobacillus growth promoter A (comprising 39g / L sodium thiosulfate, 1.5g / L ammonium chloride, 0.5g / L magnesium sulfate and 20g / L ferrous sulfate) is continuously added into the autotrophic denitrification biofilter. , the volume ratio of the added amount of the denitrifying Thiobacillus growth promoter A to the amount of water in the autotrophic denitrifying biofilter is 1:1000, denitrifying Thiobacillus is enriched and cultured, and the dissolved oxygen concentration (DO) and the redox potential (ORP) of the water in the autotrophic denitrifying biofilter are monitored; when the dissolved oxygen concentration and the redox potential of the water in the autotrophic denitrifying biofilter reach the first culture condition threshold, the next culture stage is entered; the first culture condition threshold includes: the dissolved oxygen concentration is lower than 0.5 mg / L, and the redox potential is lower than -150 mv;

[0049] In this embodiment, after 12 hours, the DO was monitored to be 0.27 mg / L and the ORP was -170 mv, and the next culture stage was started;

[0050] S2: Second training stage

[0051] The autotrophic denitrification biofilter is continuously fed with water, and the filtration rate of the second culture stage is set to 0.5 m / h; during the continuous water feeding process, a denitrifying thiobacillus growth promoter B (including 1 g / L of ammonium chloride, 0.2 g / L of magnesium sulfate, 15 g / L of ferrous sulfate and 20 g / L of sodium bicarbonate) is added to the autotrophic denitrification biofilter, and the volume ratio of the added amount of the denitrifying thiobacillus growth promoter B to the amount of water in the autotrophic denitrification biofilter is 1:10000, so as to accelerate the formation of denitrifying thiobacillus microbial film on the surface of the filler, and monitor the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent of the autotrophic denitrification biofilter; when the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent of the autotrophic denitrification biofilter reach the second culture condition threshold, the next culture stage is entered; the second culture condition threshold includes: the dissolved oxygen concentration is lower than 0.5 mg / L, the redox potential is lower than -150 mv, and the nitrate nitrogen removal rate is ≥90%;

[0052] In this embodiment, the effluent DO was monitored to be 0.44 mg / L after 12 hours; the effluent ORP was monitored to be -163 mv after 24 hours, and the nitrate nitrogen removal rate was 93%; the effluent ORP was monitored to be -143 mv after 46 hours, the DO was 0.32 mg / L, and the nitrate nitrogen removal rate was 91%, and the next culture stage began;

[0053] S3: The third training stage

[0054] The autotrophic denitrification biofilter is continuously fed with water, and a denitrifying thiobacillus growth promoter C (comprising 20 g / L of sodium bicarbonate and 1 g / L of ammonium chloride) is added to the influent, wherein the volume ratio of the added amount of the denitrifying thiobacillus growth promoter C to the amount of water in the autotrophic denitrification biofilter is 1:10000, so as to promote the rapid growth of denitrifying thiobacillus, and monitor the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent of the autotrophic denitrification biofilter; when the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent of the autotrophic denitrification biofilter reach the third culture condition threshold, the third culture stage is terminated; the third culture condition threshold includes: the dissolved oxygen concentration is lower than 0.5 mg / L; the redox potential is lower than -140 mv; and the nitrate nitrogen removal rate is ≥90%;

[0055] In this embodiment, the effluent DO was monitored to be 0.26 mg / L after 14 hours; the effluent ORP was monitored to be -143 mv after 36 hours, the nitrate nitrogen removal rate was 93%, the process was successfully started and entered the stable operation stage, and the addition of the denitrifying Thiobacillus growth promoter C was stopped.

[0056] The autotrophic denitrification biofilter of this embodiment was operated stably for 15 days, and the nitrate nitrogen removal rate was as follows: Figure 1 As shown by Figure 1It can be seen that during stable operation, the removal rate of nitrate nitrogen can reach more than 90%.

[0057] 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 rapid start-up method for a biodegradable carrier autotrophic denitrification biofilter process, characterized in that: The method comprises the following steps: S1: The first training stage Continuously feeding water into an autotrophic denitrification biofilter filled with a degradable carrier microbial membrane autotrophic denitrification filler; adding a denitrifying Thiobacillus growth promoter A to the autotrophic denitrification biofilter, monitoring the dissolved oxygen concentration and redox potential of the water in the autotrophic denitrification biofilter; and entering the next culture stage when the dissolved oxygen concentration and redox potential of the water in the autotrophic denitrification biofilter reach a first culture condition threshold; S2: Second training stage During the continuous water inflow process, a growth promoter B of Thiobacillus denitrificans is added to the autotrophic denitrification biofilter, and the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent from the autotrophic denitrification biofilter are monitored; when the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent from the autotrophic denitrification biofilter reach the second culture condition threshold, the next culture stage is entered; S3: The third training stage During the continuous water inflow process, a denitrifying Thiobacillus growth promoter C is added to the autotrophic denitrifying biological filter, and the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent from the autotrophic denitrifying biological filter are monitored; when the dissolved oxygen concentration, redox potential and nitrate nitrogen removal rate of the effluent from the autotrophic denitrifying biological filter reach the third culture condition threshold, it indicates that the process has been successfully started and entered a stable operation stage, and the addition of the denitrifying Thiobacillus growth promoter C is stopped.

2. The rapid start-up method of the biodegradable carrier autotrophic denitrification biofilter process according to claim 1, wherein: The inlet water temperature of the autotrophic denitrification biological filter is 10-38°C.

3. The rapid start-up method of the biodegradable carrier autotrophic denitrification biofilter process according to claim 1, wherein: The influent of the autotrophic denitrification biofilter includes but is not limited to at least one of domestic sewage, industrial wastewater, secondary effluent from a sewage treatment plant, total return water from a reclaimed water plant and landscape water.

4. The rapid start-up method of the biodegradable carrier autotrophic denitrification biofilter process according to claim 1, wherein: The autotrophic denitrification biological filter is an upflow or downflow biological filter.

5. The rapid start-up method of the biodegradable carrier autotrophic denitrification biofilter process according to claim 1, wherein: The denitrifying Thiobacillus growth promoter A comprises sodium thiosulfate, ammonium chloride, magnesium sulfate and ferrous sulfate.

6. The rapid start-up method of the biodegradable carrier autotrophic denitrification biofilter process according to claim 1, wherein: The denitrifying Thiobacillus growth promoter B comprises ammonium chloride, magnesium sulfate, ferrous sulfate and sodium bicarbonate.

7. The rapid start-up method of the biodegradable carrier autotrophic denitrification biofilter process according to claim 1, wherein: The denitrifying Thiobacillus growth promoter C comprises sodium bicarbonate and ammonium chloride.

8. The rapid start-up method of the biodegradable carrier autotrophic denitrification biofilter process according to claim 1, wherein: The volume ratio of the added amount of the denitrifying Thiobacillus growth promoter A to the amount of water in the autotrophic denitrification biological filter is (0.8-1.2):1000; The first culture condition thresholds include: dissolved oxygen concentration is lower than 0.5 mg / L, and redox potential is lower than -150 mv; The first culture stage takes 10-18 hours.

9. The rapid start-up method of the biodegradable carrier autotrophic denitrification biofilter process according to claim 1, wherein: In the second culture stage, the volume ratio of the added amount of Thiobacillus denitrificans growth promoter B to the amount of water in the autotrophic denitrification biological filter is (0.5-1.0): 10000; The second culture condition thresholds include: dissolved oxygen concentration is lower than 0.5 mg / L, redox potential is lower than -150 mv, and nitrate nitrogen removal rate is ≥90%; The second culture stage takes 16 to 49 hours.

10. The rapid start-up method of the biodegradable carrier autotrophic denitrification biofilter process according to claim 1, wherein: In the third culture stage, the volume ratio of the added amount of Thiobacillus denitrificans growth promoter C to the amount of water in the autotrophic denitrification biological filter is (0.8-1.2):10000; The third culture condition threshold includes: dissolved oxygen concentration is lower than 0.5 mg / L; redox potential is lower than -140 mv; nitrate nitrogen removal rate is ≥90%; The third culture stage takes 12-40 hours.

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