Method for treating wastewater from express highway service areas based on anammox-enhanced AOOA-mbbr

Abstract

The present invention relates to the field of treatment of wastewater from express highway service areas, and in particular relates to a method for treating wastewater from express highway service areas based on anammox-enhanced AOOA-MBBR. The method comprises: step I, preparing a reactor; step II, starting up the reactor and inoculating bacteria, in which step, the hydraulic retention time is gradually shortened to 20 h after an effluent stably runs for a preset time; step III, anammox enhancement, involving: after the effluent stably runs for the preset time, respectively replacing some of a filler in each tank with a filler carrying a biofilm of anammox bacteria, wherein the dissolved oxygen concentration of a first aerobic tank is 0.2 mg / L, and the dissolved oxygen concentration of a second aerobic tank is 0.5-0.8 mg / L, adding manganese sulfate to some of the wastewater from express highway service areas, and then directly pumping the resulting mixture into a second anoxic tank; and step IV, after the effluent is stable, entering a stable stage. By means of the present invention, the total nitrogen and total phosphorus of the effluent can meet corresponding discharge standards at a hydraulic retention time of 20 h, thereby improving the treatment efficiency of wastewater from express highway service areas and avoiding the problem of subsequent phosphorus removal being troublesome.

Description

A Highway Service Area Wastewater Treatment Method Based on Anaerobic Ammonia Oxidation Enhanced AOA-MBBR Technical Field

[0001] This invention relates to the field of wastewater treatment in highway service areas, specifically to a method for treating wastewater in highway service areas based on anaerobic ammonia oxidation enhanced AOOA-MBBR. Background Technology

[0002] Wastewater from highway service areas mainly consists of catering wastewater from restaurants and fecal wastewater from public toilets, accounting for over 85% of the total wastewater. The total nitrogen concentration in the wastewater is 2 to 3 times that of typical urban sewage, and it is characterized by high ammonia nitrogen concentration and a very low carbon-to-nitrogen ratio, making denitrification very difficult.

[0003] Addressing the characteristics of high ammonia nitrogen concentration and low carbon-to-nitrogen ratio in wastewater from highway service areas, the inventors of this patent previously applied for patent application number 202411483993.2, entitled "Wastewater Treatment Device and Method for Highway Service Areas Based on AOOA-MBBR Process." This method achieves denitrification by cultivating, acclimating, and enriching hydrolyzing and denitrifying bacteria on the packing material in the first anoxic tank; simultaneously achieves nitrification and denitrification by cultivating, acclimating, and enriching hydrolyzing, nitrifying, and denitrifying bacteria on the packing material in the first aerobic tank; nitrifying bacteria are cultivated, acclimated, and enriched on the packing material in the second aerobic tank to nitrify ammonia nitrogen in the effluent from the first aerobic tank; and denitrification is achieved by cultivating, acclimating, and enriching hydrolyzing and denitrifying bacteria on the packing material in the second anoxic tank. With a hydraulic retention time of 24 hours, this method achieved an average total nitrogen concentration of 14.33 mg / L in the treated effluent, with an average removal rate of 90.49%. However, when the hydraulic retention time is reduced to 20 hours, it is difficult to reduce the total nitrogen in the effluent to below 15 mg / L, so the hydraulic retention time cannot be reduced further, resulting in low wastewater treatment efficiency. Furthermore, in this patent, almost no phosphorus is removed.

[0004] Wastewater from highway service areas generally follows the Class A discharge standard of the "Discharge Standard of Pollutants for Urban Wastewater Treatment Plants" (GB18918-2002), which requires COD ≤ 50 mg / L, total nitrogen ≤ 15 mg / L, and total phosphorus ≤ 0.5 mg / L. Therefore, considering both wastewater treatment efficiency and phosphorus content in the effluent, the patent application number 202411483993.2, entitled "Wastewater Treatment Device and Method for Highway Service Areas Based on AOA-MBBR Process," does not provide ideal wastewater treatment results.

[0005] Furthermore, due to the relatively small scale of wastewater from highway service areas, conventional nitrogen and phosphorus removal processes face challenges such as insufficient influent carbon sources, complex operation (requiring precise control of operating parameters like dissolved oxygen concentration in the aerobic tank, nitrification liquor recirculation ratio, sludge recirculation ratio, sludge concentration, and sludge age), and the need to cope with seasonal temperature changes, placing high demands on the technical skills of operators. When secondary biological treatment cannot reduce total phosphorus to below 0.5 mg / L, advanced chemical phosphorus removal is required, necessitating precise control of coagulant dosage. This not only increases the length of the process flow and infrastructure costs but also raises operating costs and operational difficulty. Therefore, efficiently, cost-effectively, and simply removing total nitrogen and total phosphorus from highway service area wastewater has become a significant challenge.

[0006] Therefore, there is an urgent need for a highway service area wastewater treatment technology that can improve wastewater treatment efficiency, remove total phosphorus, and is low-cost and easy to operate. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a method for treating wastewater in highway service areas based on anaerobic ammonia oxidation enhanced AOOA-MBBR. It can make the total nitrogen and total phosphorus in the effluent meet the corresponding discharge standards (≤15mg / L and ≤0.5mg / L) when the hydraulic retention time is 20h, thereby improving the wastewater treatment efficiency of highway service areas and avoiding the troublesome problem of subsequent phosphorus removal.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is: a method for treating wastewater from highway service areas based on anaerobic ammonia oxidation enhanced AOA-MBBR, the method comprising:

[0009] Step 1, Prepare the reactor:

[0010] The reactor includes a first anoxic tank, a first aerobic tank, a second aerobic tank, and a second anoxic tank connected in sequence, with packing materials added to each tank. The first and second aerobic tanks are equipped with aeration devices. The second aerobic tank is connected to the first anoxic tank through a return pipe equipped with a return power component.

[0011] The second step is to start the reactor and inoculate it with bacteria:

[0012] Wastewater from the highway service area flows sequentially through a first anoxic tank, a first aerobic tank, a second aerobic tank, and a second anoxic tank. Specifically, the first anoxic tank is inoculated with hydrolyzing bacteria and denitrifying bacteria; the first aerobic tank is inoculated with hydrolyzing bacteria, nitrifying bacteria, and denitrifying bacteria; the second aerobic tank is inoculated with nitrifying bacteria; and the second anoxic tank is inoculated with hydrolyzing bacteria and denitrifying bacteria. The dissolved oxygen concentration in the first aerobic tank is 0.3-0.5 mg / L; the dissolved oxygen concentration in the second aerobic tank is 2.0-2.5 mg / L; the hydraulic retention time is 48 hours; and the nitrified liquid is returned from the second aerobic tank to the first anoxic tank at a return ratio of 200%.

[0013] After the water output has been running stably for the preset time, the hydraulic retention time will be gradually shortened to 36h, 24h, and 20h.

[0014] Step 3, anaerobic ammonium oxidation enhancement:

[0015] After the effluent has been running stably for a preset time, the packing material in the first anoxic tank, the first aerobic tank, the second aerobic tank, and the second anoxic tank is replaced with packing material containing biofilm-forming anaerobic ammonia-oxidizing bacteria. The dissolved oxygen concentration in the first aerobic tank is 0.2 mg / L, and the dissolved oxygen concentration in the second aerobic tank is 0.5-0.8 mg / L. Some of the wastewater from highway service areas is directly pumped into the second anoxic tank after manganese sulfate is added.

[0016] The fourth step is to wait for the water flow to stabilize before entering the stabilization phase.

[0017] Furthermore, in the third step, the packing is replaced in two stages: first, 4% of the packing in each tank is replaced, and second, 2% of the packing in each tank is replaced.

[0018] Furthermore, in the third step, the dosage of manganese is 3.5 mg / L, and the ratio of highway service area wastewater directly pumped into the second anoxic tank to highway service area wastewater pumped into the first anoxic tank is 1%.

[0019] Furthermore, the effective volume of the first anoxic tank, the first aerobic tank, the second aerobic tank, and the second anoxic tank is determined by the volume of the added packing material.

[0020] Furthermore, during the second step of inoculation:

[0021] In the first anoxic tank, hydrolytic bacteria were inoculated once every 10 days, with 200 mL each time and a bacterial concentration of 3-5 g / L, for a total of 8 inoculations; denitrifying bacteria were inoculated once every 5 days, with 300 mL each time and a bacterial concentration of 8-10 g / L, for a total of 4 inoculations.

[0022] In the first aerobic tank, hydrolyzing bacteria are inoculated once every 10 days, with 150 mL each time and a bacterial concentration of 3-5 g / L, for a total of 8 inoculations; nitrifying bacteria and denitrifying bacteria are inoculated once every 5 days, with 100 mL each time and a bacterial concentration of 8-10 g / L, for a total of 4 inoculations.

[0023] In the second aerobic tank, nitrifying bacteria are inoculated once every 5 days, with 400 mL of bacteria solution each time and a bacterial concentration of 8-10 g / L, for a total of 4 inoculations.

[0024] In the second anoxic tank, hydrolytic bacteria are inoculated once every 10 days, with 100 mL each time and a bacterial concentration of 3-5 g / L, for a total of 8 inoculations; denitrifying bacteria are inoculated once every 5 days, with 100 mL each time and a bacterial concentration of 8-10 g / L, for a total of 4 inoculations.

[0025] Furthermore, the carbon-to-nitrogen ratio (COD / TN) of wastewater from highway service areas is 1.67-1.70.

[0026] By adopting the above technical solution, the present invention has the following beneficial effects:

[0027] 1) Excellent total nitrogen removal effect: When treating wastewater from a highway service area with an extremely low carbon-to-nitrogen ratio (COD / TN = 1.67-1.70) and a hydraulic retention time of 20 hours, the total nitrogen decreased from approximately 150 mg / L to 3.36 mg / L, achieving a removal rate of 97.77%. The effluent total nitrogen was significantly lower than the Class A discharge standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002).

[0028] 2) Enhanced COD removal: By replacing the packing material with biofilm-forming anaerobic ammonia oxidizing bacteria, the COD removal effect was enhanced, resulting in a significant decrease in effluent COD from 14.58 mg / L before the enhancement of anaerobic ammonia oxidation to 9.05 mg / L, and an increase in the removal rate from 94.26% to 96.44%. The effluent COD is significantly lower than the Class A discharge standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002).

[0029] 3) Simple operation and easy control: Considering the small scale of wastewater from highway service areas and the limited technical skills of operators, the system is designed with a first aerobic tank with a dissolved oxygen level of approximately 0.2 mg / L, primarily targeting total nitrogen removal; and a second aerobic tank with a dissolved oxygen level of 0.5-0.8 mg / L, primarily targeting ammonia nitrification. Nitrate nitrogen in the effluent from the second aerobic tank can be removed in the second anoxic tank, as operators can adjust the influent ratio to the second anoxic tank based on the nitrate nitrogen concentration in the effluent from the second aerobic tank, providing sufficient electron donors for short-cut denitrification anaerobic ammonia oxidation and denitrification. This achieves efficient removal of carbon, nitrogen, and phosphorus while facilitating operator control of operating parameters.

[0030] 4) Total phosphorus was removed simultaneously: Manganese, pumped into the second anoxic tank, was used to remove phosphorus through a precipitation reaction, achieving simultaneous removal of carbon, nitrogen, and phosphorus. The total phosphorus in the effluent decreased to 0.27 mg / L, with a removal rate of 94.71%. The total phosphorus in the effluent was significantly lower than the Class A discharge standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002).

[0031] 5) Achieves simultaneous and efficient removal of carbon, nitrogen, and phosphorus: This invention can simultaneously reduce carbon, nitrogen, and phosphorus to below the Class A discharge standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002) (COD≤50mg / L, total nitrogen≤15mg / L, total phosphorus≤0.5mg / L).

[0032] In summary, this invention effectively solves the technical challenge of effluent total nitrogen and total phosphorus failing to meet the corresponding discharge standards (≤15mg / L, ≤0.5mg / L) when the hydraulic retention time is 20h. It achieves low-cost, high-efficiency, and simple-to-operate removal of COD, total nitrogen, and total phosphorus. After treatment by the anaerobic ammonia oxidation enhanced A00A-MBBR process, wastewater from highway service areas can meet the Class A discharge standards of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002), which require COD ≤50mg / L, total nitrogen ≤15mg / L, and total phosphorus ≤0.5mg / L. It has high application value and is conducive to widespread application. Attached Figure Description

[0033] Figure 1 is a flowchart of the highway service area wastewater treatment method based on anaerobic ammonia oxidation enhanced AOOA-MBBR of the present invention;

[0034] Figure 2 is a schematic diagram of the reactor of the present invention;

[0035] Figure 3 shows the COD removal effect during the treatment in an embodiment of the present invention;

[0036] Figure 4 shows the ammonia nitrogen removal effect during the treatment in the embodiment of the present invention;

[0037] Figure 5 shows the effect of nitrate nitrogen removal during the treatment in the embodiment of the present invention;

[0038] Figure 6 shows the effect of nitrite nitrogen removal in the embodiments of the present invention;

[0039] Figure 7 shows the total nitrogen removal effect during the treatment in the embodiment of the present invention;

[0040] Figure 8 shows the total phosphorus removal effect during the treatment in the embodiment of the present invention;

[0041] Figure 9 shows the amount of manganese added in the second anoxic tank 4 during the treatment in an embodiment of the present invention.

[0042] Figure 10 is an XRD pattern of the second anoxic tank 4 in an embodiment of the present invention as the treatment proceeds;

[0043] Figure 11 is a microbial detection diagram of the stable phase before the addition of anaerobic ammonia oxidizing bacteria in an embodiment of the present invention;

[0044] Figure 12 is a microbial detection diagram of the stable stage after the addition of anaerobic ammonia oxidizing bacteria in an embodiment of the present invention;

[0045] In the diagram, 1 is the first anoxic tank; 2 is the first aerobic tank; 3 is the second aerobic tank; 4 is the second anoxic tank; 5 is the packing material; 6 is the reflux power assembly; 7 is the peristaltic pump; and 8 is the aeration device. Detailed Implementation

[0046] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0047] As shown in Figures 1 and 2, a method for treating wastewater from highway service areas based on anaerobic ammonia oxidation enhanced AOOA-MBBR is described, the method comprising:

[0048] Step 1, Prepare the reactor:

[0049] The reactor includes a first anoxic tank 1, a first aerobic tank 2, a second aerobic tank 3 and a second anoxic tank 4 connected in sequence, and packing material 5 is added to each tank. Aeration devices 8 are respectively installed in the first aerobic tank 2 and the second aerobic tank 3. The second aerobic tank 3 is connected to the first anoxic tank 1 through a return pipe equipped with a return power component 6.

[0050] The reactor is 650 mm long, 220 mm wide, and 360 mm high. The effective volumes of the first anoxic tank 1, the first aerobic tank 2, the second aerobic tank 3, and the second anoxic tank 4 are 10.8 L, 8.1 L, 8.1 L, and 5.4 L, respectively. Packing material 5 is added to each of the above tanks at amounts of 10.8 L, 8.1 L, 8.1 L, and 5.4 L, respectively, ensuring that the effective volume is fully filled with packing material 5. This ensures that microorganisms adhere to the packing material 5, which is beneficial for the growth of microorganisms with long generation cycles. The packing material 5 is K1MBBR fluidized bed packing material with a diameter of 10 mm and a density of approximately 1 g / cm³. 3 Specific surface area is 60m² 2 / m 3 The packing material 5 only provides a carrier for microbial growth and cannot be decomposed by microorganisms. The carbon-to-nitrogen ratio (COD / TN) of wastewater from highway service areas is 1.67-1.70, and the simulated concentrations of COD, ammonia nitrogen, total nitrogen, and total phosphorus in wastewater from highway service areas are approximately 250 mg / L, 140 mg / L, 150 mg / L, and 5 mg / L, respectively.

[0051] The second step is to start the reactor and inoculate it with bacteria:

[0052] Wastewater from the highway service area flows sequentially through a first anoxic tank 1, a first aerobic tank 2, a second aerobic tank 3, and a second anoxic tank 4. Specifically, hydrolytic bacteria and denitrifying bacteria are inoculated in the first anoxic tank 1; hydrolytic bacteria, nitrifying bacteria, and denitrifying bacteria are inoculated in the first aerobic tank 2; nitrifying bacteria are inoculated in the second aerobic tank 3; and hydrolytic bacteria and denitrifying bacteria are inoculated in the second anoxic tank 4. The dissolved oxygen concentration in the first aerobic tank 2 is 0.3-0.5 mg / L; the dissolved oxygen concentration in the second aerobic tank 3 is 2.0-2.5 mg / L; the hydraulic retention time is 48 hours; the nitrified liquid is returned from the second aerobic tank 3 to the first anoxic tank 1 at a return ratio of 200%; after the effluent stabilizes, the hydraulic retention time is shortened to 36 hours; after the effluent stabilizes for the second time, the hydraulic retention time is shortened to 24 hours; and after the effluent stabilizes for the third time, the hydraulic retention time is shortened to 20 hours.

[0053] In this step, during the inoculation process: In the first anoxic tank 1, hydrolyzing bacteria are inoculated once every 10 days, with 200 mL each time, and a bacterial concentration of 3-5 g / L, for a total of 8 inoculations; denitrifying bacteria are inoculated once every 5 days, with 300 mL each time, and a bacterial concentration of 8-10 g / L, for a total of 4 inoculations; In the first aerobic tank 2, hydrolyzing bacteria are inoculated once every 10 days, with 150 mL each time, and a bacterial concentration of 3-5 g / L, for a total of 8 inoculations; nitrifying bacteria and denitrifying bacteria are each inoculated once every 5 days. Each time, 100 mL of bacterial solution was inoculated, with a bacterial concentration of 8-10 g / L, and inoculated 4 times. In the second aerobic tank 3, nitrifying bacteria were inoculated once every 5 days, with 400 mL of bacterial solution each time, and a bacterial concentration of 8-10 g / L, and inoculated 4 times. In the second anoxic tank 4, hydrolyzing bacteria were inoculated once every 10 days, with 100 mL of bacterial solution each time, and a bacterial concentration of 3-5 g / L, and inoculated 8 times. Denitrifying bacteria were inoculated once every 5 days, with 100 mL of bacterial solution each time, and a bacterial concentration of 8-10 g / L, and inoculated 4 times.

[0054] Step 3, anaerobic ammonium oxidation enhancement:

[0055] After the effluent has been running stably for 13 days, 6% of the packing material 5 in the first anoxic tank 1, the first aerobic tank 2, the second aerobic tank 3, and the second anoxic tank 4 is replaced twice using packing material 5 containing biofilm-forming anaerobic ammonia oxidizing bacteria (approximately 4% is replaced the first time, and approximately 2% is replaced the second time). This packing material 5 is the same as the K1MBBR fluidized bed packing material mentioned above. The dissolved oxygen concentration in the first aerobic tank 2 is controlled at approximately 0.2 mg / L, and the dissolved oxygen concentration in the second aerobic tank 3 is controlled at 0.5-0.8 mg / L. Some of the highway service area wastewater is added with manganese sulfate and then directly pumped into the second anoxic tank 4 through a peristaltic pump 7. The manganese dosage is 3.5 mg / L. The ratio of highway service area wastewater directly pumped into the second anoxic tank 4 to highway service area wastewater pumped into the first anoxic tank 1 is approximately 1%.

[0056] In the fourth step, after the effluent stabilized, the process entered a stabilization phase. With a hydraulic retention time of 20 hours, COD, total nitrogen, and total phosphorus decreased from approximately 254 mg / L, 150 mg / L, and 5 mg / L to 8.17–9.95 mg / L, 3.27–3.48 mg / L, and 0.25–0.31 mg / L, respectively, with removal rates of 96.09%–96.79%, 97.69%–97.82%, and 93.83%–95.18%. The average concentrations were 9.05 mg / L, 3.36 mg / L, and 0.27 mg / L, with average removal rates reaching 96.43%, 97.77%, and 94.71%. The effluent COD, total nitrogen, and total phosphorus levels were all significantly better than the Class A discharge standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002).

[0057] In this embodiment, the reflux ratio refers to the ratio of the flow rate of nitrified liquid refluxed from the second aerobic tank 3 to the flow rate of highway service area wastewater entering the first anoxic tank 1 from the wastewater inlet. Stable effluent means that the relative average concentrations of COD, ammonia nitrogen, total nitrogen, and total phosphorus in the effluent do not fluctuate by more than 10% over a continuous 13-day period.

[0058] It should be noted that this embodiment is a further improvement on the patent application number 202411483993.2, entitled "Wastewater Treatment Device and Method for Highway Service Area Based on AOOA-MBBR Process". The reduction of the hydraulic retention time to 24 hours in the first and second steps is the same as the wastewater treatment method in the patent application number 202411483993.2. In Figures 3 to 9, "Day 0" refers to the day after the hydraulic retention time is reduced to 20 hours. The packing material 5 for biofilm-forming anaerobic ammonia oxidizing bacteria is replaced for the first time on day 37 and for the second time on day 41. The anaerobic ammonia oxidizing bacteria packing material in the first anoxic tank 1 is placed opposite the outlet of the reflux nitrification liquid to reduce the impact of dissolved oxygen carried in the reflux nitrification liquid on the anaerobic ammonia oxidizing bacteria. It is also placed in three concentrated locations to create an aggregation effect, which is beneficial for the anaerobic ammonia oxidizing bacteria to function effectively. The anaerobic ammonia oxidizing bacteria packing material in the first aerobic tank 2 and the second aerobic tank 3 is placed near the four corners (with the aeration device 8 located in the center). The packing material is kept away from the aeration device 8 to reduce the impact of dissolved oxygen on the bacteria and create an aggregation effect, which is beneficial for their function. In the second anoxic tank 4, the packing material is placed opposite the connection between the second aerobic tank 3 and the second anoxic tank 4. This reduces the impact of dissolved oxygen carried in the effluent from the second aerobic tank 3 on the bacteria, and the packing material is concentrated in three locations to create an aggregation effect, which is beneficial for the bacteria's function. The fourth step, the stabilization phase, refers to days 69 to 81. Manganese (manganese sulfate) is added starting from day 57, with the dosage gradually increasing to 3.5 mg / L based on the effluent phosphorus concentration.

[0059] Among them, the anaerobic ammonia oxidizing bacteria in the packing material 5 are grown on the solid packing material 5, and the content can be, but is not limited to, 0.2g-0.3g / g.

[0060] The wastewater treatment methods described in the above embodiments will be explained in detail below from the perspective of their underlying principles.

[0061] To address the extremely low carbon-to-nitrogen ratio (COD / TN = 1.67-1.70) of highway service area wastewater, a wastewater treatment method based on anaerobic ammonia oxidation enhanced AOOA-MBBR was developed. Hydrolytic bacteria, denitrifying bacteria, and anaerobic ammonia oxidizing bacteria were inoculated onto the packing material 5 of the first anoxic tank 1. The influent and nitrified liquor from the second aerobic tank 3 were mixed above the packing material 5 in the first anoxic tank 1 and then flowed through the packing material 5. The denitrifying bacteria attached to the packing material 5 first utilized the readily degradable organic matter in the influent as a carbon source to reduce nitrate nitrogen carried in the returned nitrified liquor to nitrite nitrogen. The anaerobic ammonia oxidizing bacteria used ammonia nitrogen in the influent as an electron acceptor to reduce nitrite nitrogen to nitrogen gas. The remaining nitrite nitrogen was further denitrified to nitrogen gas by the denitrifying bacteria using organic matter in the influent or the hydrolysis products of recalcitrant organic matter as a carbon source. Under conditions of severe carbon source deficiency, highly efficient hydrolytic bacteria will develop on packing material 5 after long-term cultivation and acclimatization. These bacteria can hydrolyze recalcitrant organic matter in the influent into readily degradable organic matter, thus providing a carbon source for denitrification. The biofilm detached from packing material 5 can also be hydrolyzed into readily degradable organic matter by these bacteria, providing a carbon source for denitrification. Furthermore, after replacing packing material 5 with one containing anaerobic ammonia-oxidizing bacteria, the COD removal effect was enhanced; the COD concentration in the first anoxic tank 1 decreased significantly from an average of 19.25 mg / L (range 17.50 mg / L–20.82 mg / L) to an average of 13.58 mg / L (range 12.40 mg / L–14.62 mg / L), which proves the above points. The reason is that the packing material 5, which is covered with anaerobic ammonia oxidizing bacteria, not only has anaerobic ammonia oxidizing bacteria attached, but also a certain amount of hydrolytic bacteria and denitrifying bacteria. Since the generation cycle of anaerobic ammonia oxidizing bacteria is very long, sludge is usually not discharged during the biofilm formation process. The dead microorganisms are hydrolyzed and then used as carbon sources for denitrification. Therefore, the packing material 5 is covered with anaerobic ammonia oxidizing bacteria, highly efficient hydrolytic bacteria, and denitrifying bacteria, which can further degrade the recalcitrant organic matter in the first anoxic tank 1.

[0062] In the first aerobic tank 2, dissolved oxygen is controlled at approximately 0.2 mg / L. An aerobic layer dominated by ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) forms on the outer layer of the biofilm on the packing material 5, while an anoxic layer dominated by anaerobic ammonia-oxidizing bacteria, highly efficient hydrolyzing bacteria, and denitrifying bacteria forms on the inner layer of the biofilm on the packing material 5. This achieves nitrogen removal through anaerobic ammonia oxidation, short-cut denitrification, and simultaneous nitrification and denitrification. In the first aerobic tank 2, the AOB on the outer layer of the packing material 5 oxidizes ammonia nitrogen in the effluent from the first anoxic tank 1 to nitrite nitrogen. The anaerobic ammonia-oxidizing bacteria use the nitrite nitrogen produced by ammonia oxidation as an electron acceptor to oxidize ammonia nitrogen in the effluent from the first anoxic tank 1 to nitrogen gas, achieving anaerobic ammonia oxidation nitrogen removal. Denitrifying bacteria use the hydrolysis products of recalcitrant organic matter or the hydrolysis products of sloughed biofilm as a carbon source to reduce nitrite nitrogen to nitrogen gas, achieving short-cut nitrification and denitrification nitrogen removal. Simultaneously, NOB reduces some of the nitrite nitrogen... Nitrogen is further oxidized to nitrate nitrogen. Denitrifying bacteria use the hydrolysis products of recalcitrant organic matter or the hydrolysis products of sloughed biofilm as a carbon source to reduce nitrate nitrogen to nitrite nitrogen. Anaerobic ammonia oxidizing bacteria use the nitrite nitrogen produced by the denitrification of nitrate nitrogen as an electron acceptor to oxidize ammonia nitrogen in the effluent of the first anoxic tank 1 to nitrogen gas, achieving short-cut denitrification anaerobic ammonia oxidation nitrogen removal. The nitrite nitrogen produced by the denitrification of nitrate nitrogen is also further denitrified to nitrogen gas by denitrifying bacteria, achieving simultaneous nitrification and denitrification nitrogen removal. In the first aerobic tank 2, the total nitrogen decreased significantly from an average of 22.19 mg / L (range 21.71 mg / L–22.44 mg / L) to an average of 15.67 mg / L (range 15.29 mg / L–16.12 mg / L), proving that total nitrogen is removed through anaerobic ammonia oxidation, short-cut denitrification anaerobic ammonia oxidation, short-cut nitrification and denitrification, and simultaneous nitrification and denitrification. Furthermore, COD only decreased from an average of 13.58 mg / L (range 12.40 mg / L–14.62 mg / L) to an average of 11.66 mg / L (range 10.51 mg / L–12.73 mg / L), further demonstrating the effectiveness of the total nitrogen removal mechanism. This is because removing total nitrogen through anaerobic ammonia oxidation does not require a carbon source. Theoretically, removing 1 mg of total nitrogen (ammonia nitrogen + nitrate nitrogen) through short-cut denitrification anaerobic ammonia oxidation only requires 0.74 mg of COD, and removing 1 mg of total nitrogen through short-cut nitrification denitrification only requires 1.72 mg of COD.

[0063] In the second aerobic tank 3, dissolved oxygen is controlled at 0.5-0.8 mg / L. An aerobic layer dominated by ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) forms on the outer layer of the biofilm on the packing material 5, while an anoxic layer dominated by anaerobic ammonia-oxidizing bacteria, highly efficient hydrolytic bacteria, and denitrifying bacteria forms on the inner layer of the biofilm on the packing material 5. This achieves nitrogen removal through anaerobic ammonia oxidation, short-cut denitrification, short-cut nitrification-denitrification, and simultaneous nitrification-denitrification. The first aerobic tank 2 and the second aerobic tank 3 have different purposes. The first aerobic tank 2 primarily aims to remove total nitrogen while oxidizing some ammonia nitrogen to nitrate nitrogen; therefore, the dissolved oxygen in the first aerobic tank 2 is controlled at approximately 0.2 mg / L. The second aerobic tank 3 primarily aims to achieve ammonia nitrogen nitrification for ease of operation while removing some total nitrogen; therefore, the dissolved oxygen in the second aerobic tank 3 is controlled at 0.5-0.8 mg / L. The different dissolved oxygen concentrations in the first aerobic tank 2 and the second aerobic tank 3 result in different thicknesses of the aerobic and anoxic layers of the biofilm, i.e., different proportions of aerobic AOB and NOB and anoxic anaerobic ammonia-oxidizing bacteria, denitrifying bacteria, and highly efficient hydrolyzing bacteria within the biofilm. In the second aerobic tank 3, the outer layer of AOB on the packing material 5 oxidizes ammonia nitrogen in the effluent from the first aerobic tank 2 to nitrite nitrogen. Anaerobic ammonia-oxidizing bacteria use the nitrite nitrogen produced by ammonia nitrogen oxidation as an electron acceptor to oxidize ammonia nitrogen in the effluent from the first aerobic tank 2 to nitrogen gas, achieving anaerobic ammonia oxidation denitrification. Denitrifying bacteria use the hydrolysis products of recalcitrant organic matter or the hydrolysis products of detached biofilm as a carbon source to reduce nitrite nitrogen to nitrogen gas, achieving short-cut nitrification-denitrification denitrification. Simultaneously, NOB partially reduces the nitrite nitrogen... Nitrogen is further oxidized to nitrate nitrogen. Denitrifying bacteria use the hydrolysis products of recalcitrant organic matter or the hydrolysis products of sloughed biofilm as a carbon source to reduce nitrate nitrogen to nitrite nitrogen. Anaerobic ammonia oxidizing bacteria use the nitrite nitrogen produced by the denitrification of nitrate nitrogen as an electron acceptor to oxidize ammonia nitrogen in the effluent of the first aerobic tank 2 to nitrogen gas, achieving short-cut denitrification anaerobic ammonia oxidation nitrogen removal. The nitrite nitrogen produced by the denitrification of nitrate nitrogen is also further denitrified to nitrogen gas by denitrifying bacteria, achieving simultaneous nitrification and denitrification nitrogen removal. In addition, due to the high dissolved oxygen concentration in the second aerobic tank 3, the ammonia nitrogen in the effluent of the second aerobic tank 3 is reduced to an average of 0.73 mg / L (range 0.65 mg / L–0.80 mg / L), achieving the goal of ammonia nitrogen nitrification. In the second aerobic tank 3, the total nitrogen level decreased significantly from an average of 15.67 mg / L (range 15.29 mg / L–16.12 mg / L) to an average of 10.90 mg / L (range 10.31 mg / L–11.45 mg / L), demonstrating that total nitrogen was removed through anaerobic ammonia oxidation, short-cut denitrification anaerobic ammonia oxidation, short-cut nitrification-denitrification, and simultaneous nitrification-denitrification. Furthermore, the COD level only decreased from an average of 11.66 mg / L (range 10.51 mg / L–12.73 mg / L) to an average of 10.25 mg / L (range 9.49 mg / L–10.95 mg / L), further confirming the effective removal mechanisms for total nitrogen.

[0064] In the second anoxic tank 4, the total nitrogen in the effluent from the second aerobic tank 3 is mainly nitrate nitrogen (nitrate nitrogen about 8 mg / L (range 8.12 mg / L-8.28 mg / L), nitrite nitrogen about 0.9 mg / L (range 0.81 mg / L-1.01 mg / L), ammonia nitrogen about 0.7 mg / L (range 0.65 mg / L-0.80 mg / L), and organic nitrogen about 1 mg / L (range 0.46 mg / L-1.69 mg / L)), while the COD in the effluent from the second aerobic tank 3 is only 10.25 mg / L (range 9.49 mg / L-10.95 mg / L). The carbon source in the effluent from the second aerobic tank 3 is limited and cannot meet the carbon source requirements for denitrification. Furthermore, the total phosphorus concentration in the effluent from the second aerobic tank 3 is 1.89 mg / L–1.99 mg / L, which does not meet the discharge requirement of ≤0.5 mg / L. Therefore, approximately 1% manganese sulfate is added to the influent, which is then directly pumped into the second anoxic tank 4, bringing the manganese dosage to approximately 3.5 mg / L. Simultaneously, the packing material 5 containing biofilm-forming anaerobic ammonia oxidizing bacteria is replaced. In the second anoxic tank 4, phosphorus is removed through short-cut denitrification anaerobic ammonia oxidation, denitrification, and the precipitation reaction of phosphate with manganese. Highly efficient hydrolytic bacteria, denitrifying bacteria, and anaerobic ammonia oxidizing bacteria will be cultivated and acclimatized on the packing material 5 in the second anoxic tank 4. Denitrifying bacteria use readily biodegradable organic matter in the influent as a carbon source to reduce nitrate nitrogen in the effluent of the second aerobic tank 3 to nitrite nitrogen. Anaerobic ammonia-oxidizing bacteria use ammonia nitrogen in the influent as an electron donor to reduce the nitrite nitrogen produced by denitrification of nitrate nitrogen to nitrogen gas. Simultaneously, some of the nitrite nitrogen is further denitrified to nitrogen gas by denitrifying bacteria using organic matter or hydrolysis products of recalcitrant organic matter in the influent as a carbon source. Highly efficient hydrolytic bacteria also develop in the second anoxic tank 4, which can hydrolyze recalcitrant organic matter in the influent to readily biodegradable organic matter, providing a carbon source for denitrification. The biofilm detached from the packing material 5 can also be hydrolyzed into readily biodegradable organic matter by highly efficient hydrolytic bacteria, providing a carbon source for denitrification. The manganese in the influent pumped directly into the second anoxic tank 4 can react with phosphate to form a precipitation reaction, and the precipitate is manganese phosphate. The manganese phosphate generated in the second anoxic tank 4 can be adsorbed onto the packing material 5 by the biofilm, thereby removing phosphorus (Figure 10 shows that manganese and phosphorus reacted to form a precipitation reaction, and the manganese phosphate precipitate formed is attached to the packing material. The precipitate is not carried away with the effluent and will not cause secondary pollution).

[0065] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for treating wastewater from highway service areas based on anaerobic ammonia oxidation enhanced AOA-MBBR, characterized in that, The methods include: Step 1, Prepare the reactor: The reactor includes a first anoxic tank (1), a first aerobic tank (2), a second aerobic tank (3), and a second anoxic tank (4) connected in sequence, with packing material (5) added to each. The first aerobic tank (2) and the second aerobic tank (3) are respectively equipped with aeration devices (8); the second aerobic tank (3) is connected to the first anoxic tank (1) through a return pipe equipped with a return power component (6). The second step is to start the reactor and inoculate it with bacteria: Wastewater from the highway service area flows sequentially through the first anoxic tank (1), the first aerobic tank (2), the second aerobic tank (3), and the second anoxic tank (4). Specifically, hydrolytic bacteria and denitrifying bacteria are inoculated in the first anoxic tank (1); hydrolytic bacteria, nitrifying bacteria, and denitrifying bacteria are inoculated in the first aerobic tank (2); nitrifying bacteria are inoculated in the second aerobic tank (3); and hydrolytic bacteria and denitrifying bacteria are inoculated in the second anoxic tank (4). The dissolved oxygen concentration in the first aerobic tank (2) is 0.3-0.5 mg / L; the dissolved oxygen concentration in the second aerobic tank (3) is 2.0-2.5 mg / L; the hydraulic retention time is 48 hours; and the nitrified liquid is returned from the second aerobic tank (3) to the first anoxic tank (1) at a return ratio of 200%. After the water output has been running stably for the preset time, the hydraulic retention time will be gradually shortened to 36h, 24h, and 20h. Step 3, anaerobic ammonium oxidation enhancement: After the effluent has been running stably for a preset time, the packing material (5) of the first anoxic tank (1), the first aerobic tank (2), the second aerobic tank (3), and the second anoxic tank (4) are replaced with packing material (5) of biofilm-forming anaerobic ammonia oxidizing bacteria. The dissolved oxygen concentration in the first aerobic tank (2) is 0.2 mg / L, and the dissolved oxygen concentration in the second aerobic tank (3) is 0.5-0.8 mg / L. Some of the wastewater from the highway service area is directly pumped into the second anoxic tank (4) after manganese sulfate is added. The fourth step is to wait for the water flow to stabilize before entering the stabilization phase.

2. The method for treating highway service area wastewater based on anaerobic ammonia oxidation enhanced AOA-MBBR according to claim 1, characterized in that, In the third step, during the replacement of packing (5), the packing is replaced in two steps. The first step is to replace 4% of the packing (5) in each pool, and the second step is to replace 2% of the packing (5) in each pool.

3. The method for treating highway service area wastewater based on anaerobic ammonia oxidation enhanced AOA-MBBR according to claim 1, characterized in that, In the third step, the amount of manganese added is 3.5 mg / L, and the ratio of the highway service area wastewater directly pumped into the second anoxic tank (4) to the highway service area wastewater pumped into the first anoxic tank (1) is 1%.

4. The method for treating highway service area wastewater based on anaerobic ammonia oxidation enhanced AOA-MBBR according to claim 1, characterized in that, The effective volume of the first anoxic tank (1), the first aerobic tank (2), the second aerobic tank (3), and the second anoxic tank (4) is the volume of the added packing material (5).

5. The method for treating highway service area wastewater based on anaerobic ammonia oxidation enhanced AOA-MBBR according to claim 1, characterized in that, During the second step of inoculation: In the first anoxic tank (1), hydrolytic bacteria were inoculated once every 10 days, with 200 mL each time and a bacterial concentration of 3-5 g / L, for a total of 8 inoculations; denitrifying bacteria were inoculated once every 5 days, with 300 mL each time and a bacterial concentration of 8-10 g / L, for a total of 4 inoculations. In the first aerobic tank (2), hydrolytic bacteria are inoculated once every 10 days, with 150 mL each time and a bacterial concentration of 3-5 g / L, for a total of 8 inoculations; nitrifying bacteria and denitrifying bacteria are inoculated once every 5 days, with 100 mL each time and a bacterial concentration of 8-10 g / L, for a total of 4 inoculations. In the second aerobic tank (3), nitrifying bacteria are inoculated once every 5 days, with 400 mL inoculated each time and a bacterial concentration of 8-10 g / L, for a total of 4 inoculations; In the second anoxic pool (4), hydrolytic bacteria are inoculated once every 10 days, with 100 mL each time and a bacterial concentration of 3-5 g / L, for a total of 8 inoculations; denitrifying bacteria are inoculated once every 5 days, with 100 mL each time and a bacterial concentration of 8-10 g / L, for a total of 4 inoculations.

6. The method for treating highway service area wastewater based on anaerobic ammonia oxidation enhanced AOA-MBBR according to claim 1, characterized in that, The carbon-to-nitrogen ratio (COD / TN) of wastewater from highway service areas is 1.67-1.70.

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