A method for treating anaerobic ammonia-oxidizing wastewater based on a slow-release carbon source material

Abstract

This invention discloses a method for treating anaerobic ammonia oxidation wastewater based on a slow-release carbon source material, belonging to the field of wastewater treatment technology. The invention first mixes denitrifying bacterial sludge with sodium alginate solution, then solidifies it through calcium ion cross-linking to form microcapsules; lecithin, sodium acetate, and water are mixed to prepare an emulsion; after mixing the emulsion with the microcapsules, recycled oil is added for emulsification and homogenization, ultimately obtaining the slow-release carbon source material. This invention applies the slow-release carbon source material to an anaerobic ammonia oxidation system, achieving the slow and continuous release of sodium acetate and the targeted enrichment of denitrifying bacteria. While effectively removing accumulated nitrates, it avoids carbon source shock and bacterial competition, thus reducing NO2... ‑ -N and NH4 + The removal rate of -N remained stable at over 88%.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology and relates to a method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials. Background Technology

[0002] Anaerobic ammonia oxidation (ANAMMOX) is a novel biological nitrogen removal technology, but it still faces a series of key technical bottlenecks in practical engineering applications, which restrict its stability, efficiency and widespread application.

[0003] ANAMMOX bacteria use NH4 + -N and NO2 - -N represents the substrate that produces N2, but is accompanied by NO3. - -N byproduct formation. In actual treatment processes, NO3 contained in the influent or generated from partial nitrification... - -N will further exacerbate the accumulation of nitrates within the system. This continuous accumulation cannot be eliminated by the ANAMMOX pathway itself, becoming a key limiting factor for the deep removal of total nitrogen. High concentrations of nitrates not only affect the efficiency of total nitrogen removal but may also interfere with the activity of ANAMMOX bacteria through mechanisms such as feedback inhibition or alteration of redox potential.

[0004] To eliminate nitrate accumulation, denitrification and the addition of exogenous organic carbon sources are typically required. However, intermittent addition of carbon sources can lead to excessively high local concentrations, causing the denitrification process to accelerate and resulting in the accumulation of nitrite intermediates, which in turn inhibits ANAMMOX bacteria. This also causes drastic fluctuations in the pH and redox potential of the ANAMMOX system, disrupting the stable metabolic environment required by ANAMMOX bacteria. Excessive carbon sources can promote the proliferation of common heterotrophic bacteria, competing with ANAMMOX bacteria for living space and substrates, leading to the decline of the ANAMMOX community and even system failure. Furthermore, ANAMMOX bacteria have a low proliferation rate and are sensitive to environmental factors; therefore, coordinating the ecological relationship between denitrifying bacteria and ANAMMOX bacteria during the introduction of exogenous organic carbon sources and denitrifying bacteria to remove nitrates presents a significant technical challenge. Summary of the Invention

[0005] To address the problems and deficiencies in the prior art, this invention provides a method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials.

[0006] In a first aspect, the present invention provides a method for treating anaerobic ammonia oxidation wastewater based on slow-release carbon source materials, comprising: adding slow-release carbon source materials to a reactor inoculated with anaerobic ammonia oxidation sludge, then introducing wastewater and carrying out an anaerobic stirring reaction;

[0007] The slow-release carbon source material consists of a microcapsule core loaded with denitrifying bacteria and an emulsion layer covering the microcapsule core.

[0008] The core of the microcapsule loaded with denitrifying bacteria is formed by solidification of sodium alginate containing denitrifying bacteria through calcium ion cross-linking;

[0009] The emulsion layer is formed by emulsifying an aqueous phase and an oil phase containing lecithin and sodium acetate.

[0010] Furthermore, in the method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials provided by the present invention, the reactor is a sequencing batch reactor, and its single operating cycle includes: influent, anaerobic stirring reaction, sedimentation, drainage and idle, wherein the time of the anaerobic stirring reaction is 80% to 90% of the total time of a single operating cycle;

[0011] The reactor operates at a temperature of 30~35℃ and has a dissolved oxygen concentration of ≤0.5mg / L;

[0012] The mixed liquor solids concentration after inoculation with anaerobic ammonia oxidation sludge was 4.0~4.5 g / L, and the mixed liquor suspended volatile solids concentration was 2.5~3.0 g / L.

[0013] Furthermore, in the method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials provided by the present invention, the slow-release carbon source materials are added before the start of the anaerobic stirring reaction stage of each operating cycle.

[0014] Based on the sodium acetate content, the daily dosage of the slow-release carbon source material is 25-30 mg.

[0015] Furthermore, in the anaerobic ammonia-oxygen wastewater treatment method based on slow-release carbon source materials provided by the present invention, the NO2 in the wastewater... - -N concentration is 30~60 mg / L, NH4 + -N concentration is 120~160 mg / L.

[0016] Furthermore, in the method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials provided by the present invention, the denitrifying bacteria is *Stizemona stearothermiae* CGMCC 1.1803.

[0017] Furthermore, in the method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials provided by the present invention, the preparation of the slow-release carbon source materials includes: under sterile conditions, mixing denitrifying bacterial sludge and sodium alginate solution, and then cross-linking and solidifying with calcium ions to form microcapsules; mixing lecithin, sodium acetate and water to prepare an emulsion; mixing the microcapsules and the emulsion to obtain a mixture; adding recovered oil to the mixture, stirring and homogenizing to obtain the slow-release carbon source material.

[0018] Furthermore, in the method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials provided by the present invention, the volume ratio of the denitrifying bacteria sludge to the sodium alginate solution is 1:4~6.

[0019] The mass ratio of the lecithin to the sodium acetate is 1~3:2~4;

[0020] The volume ratio of the microcapsules to the emulsion is 2~4:6~8;

[0021] The volume ratio of the recovered oil to the mixture is 1~3:7~9.

[0022] Furthermore, in the method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials provided by the present invention, the homogenization rate is 6000~8000 r / min and the time is 2~4 min.

[0023] Furthermore, in the method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials provided by the present invention, the preparation of the recovered oil includes: recovering catering waste oil, melting and filtering the catering waste oil to remove impurities, heating and degassing to obtain primary oil; the primary oil is subjected to oxidation and oxidation, adsorption by a mixed adsorbent, and filtration to obtain recovered oil.

[0024] Furthermore, in the method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials provided by the present invention, the mixed adsorbent is composed of activated carbon and activated clay.

[0025] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0026] (1) This invention utilizes a dual encapsulation process of sodium alginate gel embedding and lecithin emulsification to construct a nanoscale (41~44nm), highly monodisperse (PDI<0.2), and highly stable (Zeta potential absolute value ≥56mV) denitrifying bacteria-supported sodium acetate slow-release carbon source (DNB@SA-NA). This invention combines and immobilizes denitrifying functional bacteria (Stizemonas stearothermiae) with carbon source (sodium acetate) at the nanoscale, solving the problems of easy bacterial loss and uncontrollable carbon source release. Furthermore, the recovered oil and lecithin in the denitrifying bacteria-supported sodium acetate slow-release carbon source synergistically form a stable oil-water interface layer outside the microcapsule. This interface layer, together with the internal sodium alginate gel network, constitutes a double diffusion barrier, prolonging the release cycle of sodium acetate and achieving long-term stable release of the carbon source, while avoiding anaerobic ammonia oxidation system impact.

[0027] (2) The DNB@SA-NA prepared in this invention achieves NO2 oxidation in an anaerobic ammonia oxidation system. - -N and NH4 +-N is removed simultaneously and efficiently (removal rate >88%), solving the problem of nitrate accumulation in the anaerobic ammonia oxidation process.

[0028] (3) The DNB@SA-NA prepared by the present invention is released continuously and slowly within 168 hours, avoiding the drastic pH fluctuations, nitrite accumulation and ecological inhibition of anaerobic ammonia oxidizing bacteria caused by instantaneous excess of carbon source, and providing a stable environment for microbial community.

[0029] (4) The present invention uses recycled catering waste oil as the emulsion oil phase, realizing the high-value utilization of waste, significantly reducing the cost of raw materials, and embodying the design concept of green and sustainable development. Attached Figure Description

[0030] Figure 1 Figure showing the particle size and Zeta test results for the slow-release carbon source.

[0031] Figure 2 The graph shows the polydispersity index test results for the slow-release carbon source.

[0032] Figure 3 A diagram showing the TOC release pattern of a slow-release carbon source.

[0033] Figure 4 NH4 as a slow-release carbon source for the treatment of anaerobic ammonia-oxygen wastewater + -N removal rate.

[0034] Figure 5 NO2 as a slow-release carbon source for anaerobic ammonia-oxygen wastewater treatment - -N removal rate.

[0035] In the figure above, DNB@SA-NA-1 is the slow-release carbon source prepared in Example 1, DNB@SA-NA-2 is the slow-release carbon source prepared in Example 2, DNB@SA-NA-3 is the slow-release carbon source prepared in Example 3, SA-NA is the slow-release carbon source prepared in Comparative Example 1, and DNB-NA is the slow-release carbon source prepared in Comparative Example 2; R1 is the sequencing batch reactor of Example 4, R2 is the sequencing batch reactor of Comparative Example 3, R3 is the sequencing batch reactor of Comparative Example 4, and R4 is the sequencing batch reactor of Comparative Example 5. Detailed Implementation

[0036] The technical solution of the present invention will be described below with reference to embodiments. However, the present invention is not limited to the following embodiments. Unless otherwise specified, the experimental methods and detection methods described in each embodiment are conventional methods; unless otherwise specified, the reagents and materials can be purchased commercially.

[0037] The recycled oil described in the following examples is obtained from the recycling and reprocessing of waste cooking oil collected from the Huiyuan Restaurant of Yan'an University. The preparation method of the recycled oil includes: heating the waste cooking oil until completely melted, filtering to remove solid residue, continuing to heat to boiling, and maintaining the boiling state until no more bubbles are generated to obtain initial oil. After the initial oil cools to room temperature, 20g of the initial oil is weighed, and a 3.5% hydrogen peroxide solution (10mL) is added at 50°C, and stirred for 30min. Then, a mixed adsorbent consisting of activated carbon and activated clay is added (the amount added is 50% of the initial oil mass, where the mass ratio of activated carbon to activated clay is 40%), the temperature is raised to 105°C, and the reaction is continued with stirring for 25min. Finally, the oil is filtered while hot to obtain the recycled oil.

[0038] The denitrifying bacteria involved in the following examples are *Stizemonas stearothermia* CGMCC 1.1803, which is derived from the China General Microbiological Culture Collection Center (CGMCC). *Stizemonas stearothermia* was inoculated into nutrient broth medium and cultured at 28°C to the logarithmic growth phase. The culture was then centrifuged and concentrated to obtain denitrifying bacterial sludge for later use.

[0039] Example 1

[0040] This embodiment provides a denitrifying bacteria-supported sodium acetate slow-release emulsion and its preparation method.

[0041] Sodium alginate (SA) powder was dissolved in distilled water and stirred for 5 hours. The solution was then subjected to high-speed shearing at 10,000 rpm for 5 minutes to obtain a 2% SA solution. Denitrifying bacterial sludge was mixed with the SA solution at a volume ratio of 1:5 and then added to a 1% calcium chloride solution (CaCl2) by extrusion. After standing and solidification for 40 minutes, the mixture was filtered to obtain microcapsules. All microcapsule preparation processes were performed under sterile conditions. Lecithin (2.4 g) and sodium acetate (NaAC, 3.6 g) were added to water (80 mL) at a mass ratio of 2:3 and stirred for 10 minutes to obtain a Na-emulsion. Microcapsules were slowly added to the Na-emulsion at a volume ratio of 3:7 and stirred at 200 rpm to obtain a mixture. Recovered oil was slowly added to the mixture (recovered oil to mixed solution volume ratio of 1:9) and stirred for 2 hours to obtain a crude emulsion. The crude emulsion was homogenized at 8000 r / min for 3 min using a high-speed disperser to obtain DNB@SA-NA-1 (a slow-release carbon source of sodium acetate supported on denitrifying bacteria).

[0042] Example 2

[0043] This embodiment provides a denitrifying bacteria-supported sodium acetate slow-release emulsion and its preparation method.

[0044] Sodium alginate (SA) powder was dissolved in distilled water and stirred for 2 hours. The solution was then subjected to high-speed shearing at 12000 rpm for 2 minutes to obtain a 5% SA solution. Denitrifying bacterial sludge was mixed with the SA solution at a volume ratio of 1:6 and then added to a 3% calcium chloride solution (CaCl2) by extrusion. After standing and solidification for 30 minutes, the mixture was filtered to obtain microcapsules. All microcapsule preparation processes were performed under aseptic conditions. Lecithin (2.0 g) and sodium acetate (NaAC, 4.0 g) were added to water (100 mL) at a mass ratio of 1:2 and stirred for 15 minutes to obtain a Na-emulsion. Microcapsules were slowly added to the Na-emulsion at a volume ratio of 4:6 and stirred at 150 rpm to obtain a mixture. Recovered oil was slowly added to the mixture (recovered oil to mixed solution volume ratio of 2:8) and stirred for 3 hours to obtain a crude emulsion. The crude emulsion was homogenized at 6000 r / min for 4 min using a high-speed disperser to obtain DNB@SA-NA-2 (a slow-release carbon source of sodium acetate supported on denitrifying bacteria).

[0045] Example 3

[0046] This embodiment provides a denitrifying bacteria-supported sodium acetate slow-release emulsion and its preparation method.

[0047] Sodium alginate (SA) powder was dissolved in distilled water and stirred for 6 hours, followed by high-speed shearing at 8000 rpm for 5 minutes to obtain a 4% SA solution. Denitrifying bacterial sludge was mixed with the SA solution at a volume ratio of 1:4 and then added to a 2% calcium chloride solution (CaCl2) by extrusion. After standing and solidification for 50 minutes, the mixture was filtered to obtain microcapsules. The microcapsule preparation process was carried out under sterile conditions. Lecithin (2.1 g) and sodium acetate (NaAC, 2.8 g) were added to water (100 mL) at a mass ratio of 3:4 and stirred for 20 minutes to obtain a Na-emulsion. The microcapsules were slowly added to the Na-emulsion at a volume ratio of 2:8 and stirred at 250 rpm to obtain a mixture. Recovered oil was slowly added to the mixture (recovered oil to mixed solution volume ratio of 3:7) and stirred for 5 hours to obtain a crude emulsion. The crude emulsion was homogenized at 6000 r / min for 2 min using a high-speed disperser to obtain DNB@SA-NA-3 (a slow-release carbon source of sodium acetate supported on denitrifying bacteria).

[0048] Comparative Example 1

[0049] This embodiment provides a sodium acetate sustained-release emulsion and its preparation method.

[0050] Sodium alginate (SA) powder was dissolved in distilled water and stirred for 5 hours. The solution was then subjected to high-speed shearing at 10,000 rpm for 5 minutes to obtain a 2% SA solution. The SA solution was added to a 1% calcium chloride solution (CaCl2) by extrusion. After standing and solidification for 40 minutes, the solution was filtered to collect microcapsules. All microcapsule preparation was performed under sterile conditions. Lecithin (2.4 g) and sodium acetate (NaAC, 3.6 g) were added to water (80 mL) and stirred for 10 minutes to obtain a homogeneous NA-emulsion. Microcapsules were slowly added to the NA-emulsion at a volume ratio of 3:7 and stirred at 200 rpm to obtain a mixed solution. Recycled oil was slowly added to the mixed solution (recycled oil to mixed solution volume ratio of 1:9), and stirred for 2 hours to obtain a crude emulsion. The crude emulsion was homogenized at 8000 rpm for 3 minutes using a high-speed disperser to obtain SA-NA (sodium acetate slow-release carbon source).

[0051] Comparative Example 2

[0052] This embodiment provides a denitrifying bacteria and sodium acetate slow-release emulsion and its preparation method.

[0053] Lecithin (2.4 g), sodium acetate (NaAC, 3.6 g), and denitrifying bacteria sludge (3.5 mL) were added to water (80 mL) and stirred for 10 min to obtain a uniform DNB / NA emulsion. Recycled oil was slowly added to the DNB / NA emulsion (recycled oil to DNB / NA emulsion volume ratio 1:9), and stirred for 2 h to obtain a crude emulsion. The crude emulsion was homogenized at 8000 rpm for 3 min using a high-speed disperser to obtain DNB-NA (denitrifying bacteria and sodium acetate slow-release carbon source).

[0054] DNB@SA-NA (DNB@SA-NA-1, DNB@SA-NA-2 and DNB@SA-NA-3), SA-NA and DNB-NA were diluted 100 times, and the particle size, polydispersity index (PDI) and zeta potential of the nanoemulsion were measured using a nanoparticle size and zeta potential analyzer.

[0055] The average particle size of DNB@SA-NA (denitrifying bacteria-supported sodium acetate slow-release carbon source) prepared in this invention is 41~44 nm. Figure 1 ), and the PDI values ​​were 0.18, 0.14, and 0.17, respectively. Figure 2 The absolute value of the Zeta potential is ≥56mV. Figure 1The results indicate that DNB@SA-NA has a uniform particle size distribution, good monodispersity, and excellent electrostatic repulsion stability. Compared with SA-NA, the particle size of DNB@SA-NA is significantly larger than that of SA-NA (26.24 nm), but its PDI value is close to that of SA-NA (0.08), indicating that the successful encapsulation of denitrifying bacteria cells is the main reason for the increased particle size, and the encapsulation process did not destroy the uniformity of material dispersion. Comparative Example 2, which emulsifies denitrifying bacteria sludge with sodium acetate (DNB-NA), has a particle size of 115.69 nm, a PDI of 0.22, and a Zeta potential of -29.53 mV. This indicates that the denitrifying bacteria cells were not encapsulated, making it difficult to control their dispersion in the emulsion, resulting in a coarse system with larger size, less uniform distribution, and insufficient electrostatic stability.

[0056] Take 5 mL of DNB@SA-NA (DNB@SA-NA-1, DNB@SA-NA-2, and DNB@SA-NA-3), SA-NA, and DNB-NA respectively, and mix them with 100 mL of deionized water. At room temperature, take 2 mL of the supernatant at 0, 24, 48, 72, 96, 120, 144, and 168 h, mix it with 3 mL of anhydrous ethanol, filter it through a 0.22 μm filter membrane, and determine the TOC value (total organic carbon content).

[0057] like Figure 3 As shown, the TOC concentration in the aqueous phase of DNB@SA-NA showed a stable and continuous upward trend during the 168-hour release period, without any sudden release. The entire release curve was smooth, indicating that the diffusion rate of sodium acetate from the interior of DNB@SA-NA was effectively regulated by the sodium alginate gel and lecithin membrane. DNB-NA released 254.3 mg / L of TOC within 24 hours, accounting for more than 70% of the total release, after which the release almost stopped, indicating that its structure could not effectively encapsulate and continuously release sodium acetate and denitrifying bacteria cells. The release amount of DNB@SA-NA in 24 hours (70.3~96.5 mg / L) was much lower than that of DNB-NA, and it continued to release within 168 hours, proving that the microcapsules effectively delayed the rapid dissolution of the core material. Compared to SA-NA, the final cumulative release of DNB@SA-NA (590~636 mg / L) is slightly lower than that of SA-NA (720.3 mg / L). This is because all carbon sources in SA-NA can be used for release, while some carbon sources in DNB@SA-NA have been metabolized and consumed by the encapsulated denitrifying bacteria before release, which also confirms the activity of the bacteria inside DNB@SA-NA.

[0058] Example 4

[0059] This embodiment provides a method for treating anaerobic ammonia-oxygen wastewater using DNB@SA-NA-1.

[0060] This embodiment uses a single sequencing batch reactor (SBR) with an effective volume of 2.5L, designated R1. The SBR is placed in a constant-temperature water bath at 32±2℃ and equipped with a mechanical stirrer (100~150 r / min) to ensure uniform sludge mixing. The SBR operates in a strictly anaerobic mode, running two cycles per day, each cycle lasting 12 hours (including 10 min of influent, 630 min of anaerobic stirring reaction, 40 min of sedimentation, 10 min of effluent discharge, and 30 min of idle time). The dissolved oxygen concentration in the SBR is ≤0.5 mg / L. The inoculum for the SBR is sourced from mature anaerobic ammonia oxidation sludge that has been stably operating at a wastewater treatment company in Yan'an City. The mixed liquor solids concentration and suspended volatile solids concentration are 4.3 g / L and 2.8 g / L, respectively.

[0061] All embodiments in this study used artificially simulated wastewater, and the water quality parameters are shown in Table 1.

[0062] Table 1 Water quality parameters of artificially simulated wastewater

[0063]

[0064] After each drainage cycle, add 5 mL of DNB@SA-NA-1 (equivalent to adding 15 mg of sodium acetate and 20.5 mg of denitrifying bacteria wet weight) to the sequencing batch reactor. Measure the NH4 content of the influent and effluent daily. + -N and NO2 - -N concentration, run for 30 days.

[0065] Comparative Example 3

[0066] The experimental setup, operating conditions, and influent water quality of this comparative example are exactly the same as those of Example 4. The only difference is that 5 mL of SA-NA is added to the sequencing batch reactor (R2) each cycle.

[0067] Comparative Example 4

[0068] The experimental setup, operating conditions, and influent water quality of this comparative example are exactly the same as those of Example 4. The only difference is that 5 mL of DNB-NA is added to the sequencing batch reactor (R3) each cycle.

[0069] Comparative Example 5

[0070] The experimental setup, operating conditions, and influent water quality of this comparative example are exactly the same as those of Example 4. The only difference is that 15 mg of sodium acetate and 20.5 mg (wet weight) of denitrifying bacteria are added to the sequencing batch reactor (R4) each cycle.

[0071] NH4 in Example 4 (R1) +The removal rate of -N increased from 68.5% to over 80% in the initial stage of operation (days 1-7), and remained stable at a high level of 90%-96% for the following 23 days (average removal rate >92%). Figure 4 NO2 - The removal rate of -N rapidly increased from 51.9% to 89.5% within 7 days, and remained stable at a level of 87%~92% for the following 23 days (average removal rate >88%). Figure 5 NO2 in Example 4 - -N and NH4 + -N co-converted into nitrogen gas, indicating that DNB@SA-NA-1 not only did not interfere with the core metabolic function of anaerobic ammonia oxidizing bacteria, but also allowed its ammonia oxidation activity to be fully utilized and maintained in a long-term stable manner. Furthermore, based on the stoichiometry of the anaerobic ammonia oxidation reaction and the high total nitrogen removal rate of the system, it can be inferred that the nitrate (NO3) produced by the anaerobic ammonia oxidation reaction... - -N) has been removed synchronously, and no accumulation has occurred. NH4 + -N and NO2 - The smoothness and non-decay characteristics of the -N removal rate curve, combined with Figure 3 The TOC release pattern of DNB@SA-NA indicates that the internal physicochemical environment (such as pH) of the anaerobic ammonia oxidation system is highly stable. Comparative Example 3 (R2) NH4 + Although the removal rate of -N gradually increased, it eventually stabilized at 55%~58%. Figure 4 ), and fluctuates greatly, NO2 - -N removal rate is 53%~55% ( Figure 5 This indicates that providing only sodium acetate without loading denitrifying bacteria will stimulate the excessive proliferation of the system's inherent heterotrophic microorganisms, which will then compete with anaerobic ammonia-oxidizing bacteria for NO2 consumption. - -N substrates, along with their incomplete denitrification process leading to nitrite accumulation, jointly restrict the activity of anaerobic ammonia oxidizing bacteria. Comparative Example 4 (R3) NH4 + -N removal rate is 51%~54% ( Figure 4 NO2 - -N removal rate is 57%~59% ( Figure 5 The levels of NH4 in Comparative Example 5 (R4) were significantly lower than those in Example 4. This is because the lack of alginate encapsulation structure led to an imbalance between sodium acetate and the release of denitrifying bacteria, easily causing local carbon source shocks and dysbiosis, thus continuously interfering with the activity of anaerobic ammonia-oxidizing bacteria. + -N removal rate is only 38%~45% ( Figure 4 NO2 - -N removal rate is 45%~48% ( Figure 5The fact that both fluctuate wildly proves that the direct addition of sodium acetate and denitrifying bacteria will cause periodic shocks to the anaerobic ammonia oxidation system, severely damaging its ecological and chemical stability, and causing the activity of anaerobic ammonia oxidizing bacteria to be unable to be maintained stably.

[0072] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art through related deductions and substitutions based on the inventive concept, without inventive effort, are within the scope of protection of the present invention.

Claims

1. A method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials, characterized in that, include: After adding slow-release carbon source material to the reactor inoculated with anaerobic ammonia oxidation sludge, wastewater is introduced and anaerobic stirring reaction is carried out. The slow-release carbon source material consists of a microcapsule core loaded with denitrifying bacteria and an emulsion layer covering the microcapsule core. The core of the microcapsule loaded with denitrifying bacteria is formed by solidification of sodium alginate containing denitrifying bacteria through calcium ion cross-linking; The emulsion layer is formed by emulsifying an aqueous phase and an oil phase containing lecithin and sodium acetate. Under sterile conditions, denitrifying bacterial sludge and sodium alginate solution were mixed and then cross-linked and solidified with calcium ions to form microcapsules; lecithin, sodium acetate and water were mixed to prepare an emulsion; the microcapsules and emulsion were mixed to obtain a mixture; recycled oil was added to the mixture, stirred and homogenized to obtain the slow-release carbon source material.

2. The method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials according to claim 1, characterized in that, The reactor is a sequencing batch reactor, and its single operating cycle includes: influent, anaerobic stirring reaction, sedimentation, drainage and idle. The time of the anaerobic stirring reaction is 80% to 90% of the total time of a single operating cycle. The reactor operates at a temperature of 30~35℃ and has a dissolved oxygen concentration of ≤0.5mg / L; The mixed liquor solids concentration after inoculation with anaerobic ammonia oxidation sludge was 4.0~4.5 g / L, and the mixed liquor suspended volatile solids concentration was 2.5~3.0 g / L.

3. The method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials according to claim 2, characterized in that, The slow-release carbon source material is added before the start of the anaerobic stirring reaction stage of each operating cycle; Based on the sodium acetate content, the daily dosage of the slow-release carbon source material is 25-30 mg.

4. The method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials according to claim 1, characterized in that, NO2 in the wastewater - -N concentration is 30~60 mg / L, NH4 + -N concentration is 120~160 mg / L.

5. The method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials according to claim 1, characterized in that, The denitrifying bacteria is *Stizemonas stearothermia* CGMCC 1.1803.

6. The method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials according to claim 1, characterized in that, The volume ratio of the denitrifying bacteria sludge to the sodium alginate solution is 1:4~6; The mass ratio of the lecithin to the sodium acetate is 1~3:2~4; The volume ratio of the microcapsules to the emulsion is 2~4:6~8; The volume ratio of the recovered oil to the mixture is 1~3:7~9.

7. The method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials according to claim 1, characterized in that, The homogenization process is carried out at a speed of 6000~8000 r / min for 2~4 min.

8. The method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials according to claim 1, characterized in that, The preparation of the recovered oil includes: recovering waste cooking oil, melting and filtering the waste cooking oil to remove impurities, heating and degassing to obtain primary oil; the primary oil is subjected to oxidation and hydrogenation, adsorption with a mixed adsorbent, and filtration to obtain recovered oil.

9. The method for treating anaerobic ammonia-oxygen wastewater based on slow-release carbon source materials according to claim 8, characterized in that, The mixed adsorbent is composed of activated carbon and activated clay.

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