Method for compositely regulating and controlling whole-course autotrophic nitrogen removal process by hydrazine and hydroxylamine

Abstract

The invention provides a hydrazine and hydroxylamine composite regulation and control method for a whole-course autotrophic nitrogen removal process, and belongs to the technical field of wastewater treatment.The method comprises the following steps that S1, an up-flow anaerobic sludge blanket reactor is adopted, and anaerobic ammonia oxidation (AnAOB) granular sludge is inoculated; s2, preparing simulated wastewater, and setting operation conditions including inlet water ammonia nitrogen concentration, continuous aeration concentration, temperature, inlet water pH and hydraulic retention time; s3, continuously monitoring the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the effluent; and S4, determining whether to start the CANON process or not according to the criterion that the molar ratio of the effluent nitrate nitrogen concentration to the inflow ammonia nitrogen concentration is 0.11. According to the method for compositely regulating and controlling the whole-course autotrophic nitrogen removal process through hydrazine and hydroxylamine, the CANON process can be rapidly started and stably operated, the aeration requirement is synchronously reduced, and the operation cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a method for a whole-process autotrophic denitrification process controlled by composite regulation of hydrazine and hydroxylamine. Background Art

[0002] The traditional nitrification and denitrification process not only has high operating costs when treating nitrogen-rich wastewater, especially ammonia nitrogen wastewater, but also has the risk of secondary pollution. This is because the process requires continuous aeration during the nitrification stage and the addition of an organic carbon source as an electron donor during the denitrification stage, which increases operating costs.

[0003] In order to cope with the increasingly severe nitrogen pollution problem, the fully autotrophic denitrification (CANON) process came into being. Compared with the traditional process, the CANON process can save up to 62.5% of the aeration cost and does not require the supply of organic matter, thus greatly reducing the process operation cost. However, the start-up, stability and efficient operation of the CANON process face many challenges. Among them, enriching and balancing the functional bacterial flora ammonia oxidizing bacteria (AOB) and anaerobic ammonia oxidizing bacteria (AnAOB), and excluding nitrite oxidizing bacteria (NOB) are the key to realizing the CANON process.

[0004] In the actual wastewater treatment process, common control methods such as dissolved oxygen, free ammonia and free nitrite are often difficult to quickly and effectively achieve the startup and stable operation of the CANON process. Hydrazine and hydroxylamine, as important metabolic intermediates of typical functional microorganisms AOB and AnAOB in the CANON process, have potential application value in regulating the CANON process. Hydrazine, as an important metabolite of AnAOB, can promote the enrichment and corresponding metabolic processes of AnAOB, while inhibiting AOB and NOB, and the inhibitory effect on NOB is stronger than AOB. Hydroxylamine, as a strong reducing agent, can inhibit NOB from further oxidizing nitrite nitrogen, thereby promoting the activity of AOB and improving its competitive advantage with NOB.

[0005] Although hydrazine and hydroxylamine each have certain advantages in wastewater denitrification, their use alone is often difficult to achieve the ideal denitrification effect. Therefore, the combined use of hydrazine and hydroxylamine has become a new attempt. However, due to the weak toxicity of hydrazine and hydroxylamine, their long-term addition to the above environment can easily cause the inactivation or even death of functional microorganisms. Therefore, it is necessary to effectively quantify the dosage and addition time when they are used in combination, so as to achieve the effect of starting and stabilizing the operation of the process without killing the functional microorganisms. Summary of the invention

[0006] The purpose of the present invention is to provide a method for the whole autotrophic denitrification process by composite regulation of hydrazine and hydroxylamine, which can quickly start and stably operate the CANON process and simultaneously reduce the aeration demand and reduce the operating cost.

[0007] To achieve the above object, the present invention provides a method for the whole autotrophic denitrification process by composite regulation of hydrazine and hydroxylamine, comprising the following steps: S1, using an upflow anaerobic sludge blanket reactor and inoculating AnAOB granular sludge; S2. Prepare simulated wastewater and set operating conditions, including influent ammonia nitrogen concentration, continuous aeration concentration, temperature, influent pH and hydraulic retention time; S3. Continuously monitor the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the effluent; S4, using the molar ratio of effluent nitrate nitrogen concentration to influent ammonia nitrogen concentration of 0.11 as a criterion to determine whether to start the CANON process; When the molar ratio of the nitrate nitrogen concentration in the effluent to the ammonia nitrogen concentration in the influent is less than 0.11, the operating conditions in step S2 are maintained for 30 days. If the CANON process cannot be started, 1.0 mg·L -1 Hydrazine and 5.0mg·L -1 Hydroxylamine, and adjust the dissolved oxygen concentration to 0.5~0.7mg·L -1 , operate the upflow anaerobic sludge blanket reactor and keep the operating conditions in step S2 unchanged, add hydrazine and hydroxylamine until the CANON process is successfully started, stop adding hydrazine and hydroxylamine, and keep the operating conditions unchanged.

[0008] Preferably, in step S2, the simulated wastewater includes an inorganic salt buffer and trace elements, the trace elements include trace element 1 and trace element 2, and the solvent is tap water; The inorganic salt buffer includes: (NH4)2SO4:KH2PO4:CaCl2:MgSO4·7H2O=140:6.75:34:75; Trace elements 1 include: EDTA: FeSO4·7H2O=5000:9140; Trace elements 2 include: EDTA: MnCl2·4H2O: ZnSO4·7H2O: CuSO4·5H2O: CoCl2·2H2O: NaMoO4·2H2O: NiCl2·6H2O: H3BO3=15000: 990: 430: 250: 240: 220: 210: 14.

[0009] Preferably, in step S2, the influent ammonia nitrogen concentration is 35-140 mg·L -1 , continuous aeration concentration 2.0~3.0mg·L -1 , ambient temperature is 34~36℃, inlet pH is 7.8~8.0, and hydraulic retention time is 2~3h.

[0010] Therefore, the present invention adopts the above-mentioned method of composite regulation of hydrazine and hydroxylamine throughout the autotrophic denitrification process, and the beneficial technical effects are as follows: (1) By adding hydrazine and hydroxylamine in combination, the present invention successfully achieved stable regulation of the entire autotrophic denitrification process (CANON). This method not only promoted the enrichment and balance of ammonia oxidizing bacteria (AOB) and anaerobic ammonia oxidizing bacteria (AnAOB), but also significantly inhibited the activity of nitrite oxidizing bacteria (NOB). More importantly, during the composite regulation process, the supply of dissolved oxygen was simultaneously reduced, thereby effectively reducing the aeration demand, which is of great significance for reducing energy consumption and operating costs; (2) When treating nitrogen-rich wastewater, the traditional nitrification and denitrification process requires the addition of an organic carbon source as an electron donor for the denitrification process, and sufficient oxygen needs to be provided to complete the nitrification process, which leads to higher operating costs. However, the present invention, through the combined regulation of hydrazine and hydroxylamine, not only does it not require the addition of an organic carbon source, but it also further reduces the operating cost by reducing the aeration demand. In addition, since the combined use of hydrazine and hydroxylamine has less toxic effects on functional microorganisms than single long-term use, it also extends the stable operation cycle of the process and reduces the cost of maintenance and equipment replacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a flow chart of a method for a whole-process autotrophic denitrification process using hydrazine and hydroxylamine combined regulation according to the present invention; Figure 2 Optimize concentrations for hydrazine and hydroxylamine; Figure 3 This is the change in CANON process metering ratio. DETAILED DESCRIPTION

[0012] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0013] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0014] Embodiment 1 Figure 1 The flowchart of the method of the present invention for the composite regulation of hydrazine and hydroxylamine for the whole autotrophic denitrification process is as follows. In this embodiment, an upflow anaerobic sludge blanket reactor is taken, named R1 and has an effective volume of 1.0L, and is inoculated with 0.5L of anaerobic ammonium oxidation granular sludge, and its volatile suspended solids concentration is detected to be 2.75g·L -1 , i.e., each contained 1.38 g of volatile suspended solids.

[0015] The influent of R1 is simulated wastewater, including inorganic salt buffer and trace elements, the trace elements include trace element 1 and trace element 2, and the solvent is tap water.

[0016] The inorganic salt buffer includes: (NH4)2SO4:KH2PO4:CaCl2:MgSO4·7H2O=140:6.75:34:75; Trace elements 1 include: EDTA: FeSO4·7H2O=5000:9140; Trace elements 2 include: EDTA: MnCl2·4H2O: ZnSO4·7H2O: CuSO4·5H2O: CoCl2·2H2O: NaMoO4·2H2O: NiCl2·6H2O: H3BO3=15000: 990: 430: 250: 240: 220: 210: 14.

[0017] The reactor maintained a hydraulic retention time of 2.4 h and an influent ammonia nitrogen concentration of 140 mg L -1 , dissolved oxygen concentration is 2.0~3.0mg·L -1 Run the reactor.

[0018] The concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the effluent were continuously monitored, and the molar ratio of effluent nitrate nitrogen concentration to influent ammonia nitrogen concentration of 0.11 was used as the criterion to determine whether the CANON process should be started.

[0019] When the molar ratio of the effluent nitrate nitrogen concentration to the influent ammonia nitrogen concentration is greater than 0.11, the CANON process is started.

[0020] When the molar ratio of nitrate nitrogen concentration in the effluent to ammonia nitrogen concentration in the inlet is less than 0.11, the above conditions are maintained for 30 days. If the CANON process has not started after 30 days, 1.0 mg·L -1 Hydrazine and 5.0mg·L -1 Hydroxylamine ( Figure 2 To optimize the concentration of hydrazine and hydroxylamine, Figure 2 It can be seen that at 1.0 mg·L -1 Hydrazine and 5.0mg·L -1 When hydroxylamine is used in combination, the SAA value of anaerobic ammonia oxidation activity is the highest, indicating that the functional microbial activity is the highest and is more conducive to the start-up of the CANON process). Simultaneously adjust the dissolved oxygen concentration to 0.5~0.7mg·L -1The reactor was operated, and the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the effluent were continuously monitored. The molar ratio of effluent nitrate nitrogen concentration to influent ammonia nitrogen concentration was 0.11, which was used as the criterion to determine whether the CANON process was started. Under this operating condition, the reactor was started on the 17th day and could run stably for 30 days. At the same time, after stopping the addition of hydrazine and hydroxylamine, the CANON process could still run stably.

[0021] The above data show that the composite addition of 1.0 mg·L -1 Hydrazine and 5.0mg·L -1 After 17 days of hydroxylamine addition, the CANON process can be started and run stably without stopping the addition of hydrazine and hydroxylamine. The CANON process can still maintain stable operation and simultaneously reduce the aeration demand and reduce the operating cost. Figure 3 As shown in the figure, MRNN refers to the molar ratio of runoff nitrate nitrogen concentration to inlet ammonia nitrogen concentration. After running reactor R1, the ratio kept fluctuating and did not reach the theoretical stoichiometric ratio of 0.11, close to the simple control operating conditions, indicating that the CANON process was not started. After adding optimized hydrazine and hydroxylamine to reactor R1, it was found that the ratio gradually stabilized and approached 0.11. It is believed that the CANON process was successfully started and operated stably after the combined regulation of hydrazine and hydroxylamine.

[0022] It is worth noting that the contents not elaborated in detail in the present invention are all prior art and are well known to those skilled in the art.

[0023] Therefore, the present invention adopts the above-mentioned method of composite regulation of hydrazine and hydroxylamine throughout the autotrophic denitrification process, which can quickly start and stably operate the CANON process and simultaneously reduce the aeration demand and reduce the operating cost.

[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for the whole autotrophic denitrification process by composite regulation of hydrazine and hydroxylamine, characterized in that: The following steps are involved: S1, using an upflow anaerobic sludge blanket reactor and inoculating AnAOB granular sludge; S2. Prepare simulated wastewater and set operating conditions, including influent ammonia nitrogen concentration, continuous aeration concentration, temperature, influent pH and hydraulic retention time; S3. Continuously monitor the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the effluent; S4, using the molar ratio of nitrate nitrogen concentration in the effluent to ammonia nitrogen concentration in the inlet as 0.11 as a criterion to determine whether to start the CANON process; When the molar ratio of the nitrate nitrogen concentration in the effluent to the ammonia nitrogen concentration in the influent is less than 0.11, the operating conditions in step S2 are maintained for 30 days. If the CANON process cannot be started, 1.0 mg·L -1 Hydrazine and 5.0mg·L -1 Hydroxylamine, and adjust the dissolved oxygen concentration to 0.5~0.7mg·L -1 , operate the upflow anaerobic sludge blanket reactor and keep the operating conditions in step S2 unchanged, add hydrazine and hydroxylamine until the CANON process is successfully started, stop adding hydrazine and hydroxylamine, and keep the operating conditions unchanged.

2. The method of a hydrazine and hydroxylamine composite control whole autotrophic denitrification process according to claim 1, characterized in that: In step S2, the simulated wastewater includes an inorganic salt buffer and trace elements, the trace elements include trace element 1 and trace element 2, and the solvent is tap water; The inorganic salt buffer includes: (NH4)2SO4:KH2PO4:CaCl2:MgSO4·7H2O=140:6.75:34:75; Trace elements 1 include: EDTA: FeSO4·7H2O=5000:9140; Trace elements 2 include: EDTA: MnCl2·4H2O: ZnSO4·7H2O: CuSO4·5H2O: CoCl2·2H2O: NaMoO4·2H2O: NiCl2·6H2O: H3BO3=15000: 990: 430: 250: 240: 220: 210:

14.

3. The method of a hydrazine and hydroxylamine composite control whole autotrophic denitrification process according to claim 1, characterized in that: In step S2, the influent ammonia nitrogen concentration is 35~140 mg·L -1 , continuous aeration concentration 2.0~3.0mg·L -1 , ambient temperature is 34~36℃, inlet pH is 7.8~8.0, and hydraulic retention time is 2~3h.

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