Highway service area wastewater treatment device and method based on AOOA-MBBR process

Abstract

The invention relates to the field of municipal wastewater treatment, in particular to an expressway service area wastewater treatment device and method based on an AOOA-MBBR technology. The device comprises a first anoxic tank, a first aerobic tank, a second aerobic tank and a second anoxic tank which are communicated in sequence and are respectively filled with MBBR (Moving Bed Biofilm Reactor) filler, and the volume of the filled MBBR filler is used as an effective volume; aeration devices are respectively arranged in the first aerobic tank and the second aerobic tank; the first anoxic tank is used for inoculating hydrolytic bacteria and denitrifying bacteria; the first aerobic tank is used for inoculating hydrolytic bacteria, nitrifying bacteria and denitrifying bacteria; the second aerobic tank is used for inoculating nitrifying bacteria, and the second anoxic tank is used for inoculating hydrolytic bacteria and denitrifying bacteria; the second aerobic tank is communicated with the first anoxic tank through a return pipe, and the return pipe is provided with a return power assembly. The invention solves the problems of high operation cost, poor denitrification effect and high sludge yield due to the need of an external carbon source / electron donor in the existing treatment of the expressway service wastewater with the extremely low carbon-nitrogen ratio.

Description

Technical Field

[0001] The present invention relates to the field of municipal wastewater treatment, and in particular to a highway service area wastewater treatment device and method based on an AOOA-MBBR process. Background Art

[0002] Wastewater in highway service areas is mainly composed of restaurant wastewater and fecal wastewater from public toilets, accounting for more than 85% of the total wastewater. The wastewater has the following characteristics:

[0003] (1) High ammonia nitrogen concentration, up to 150 mg / L;

[0004] (2) The carbon-nitrogen ratio is low, COD / TN is less than 2, which belongs to high ammonia nitrogen and low carbon-nitrogen ratio wastewater.

[0005] Theoretically, 2.86 mg COD is required to reduce 1 mg of nitrate nitrogen to nitrogen gas, but in practice, 4-5 mg COD is usually consumed. Due to the serious lack of carbon sources in the wastewater, denitrification is difficult. 2 O process, biological contact oxidation process, SBR process, MBR process and other treatments have poor denitrification effects. In addition, the existing technology usually uses traditional nitrification / denitrification technology for denitrification, but due to insufficient carbon sources in the influent, in the actual treatment process, additional carbon sources such as sodium acetate and ethanol need to be added to ensure the denitrification effect, which greatly increases the operating cost.

[0006] With the improvement of sewage discharge standards, traditional nitrification / denitrification denitrification technology has obviously been difficult to meet the discharge standards when treating low carbon-nitrogen ratio wastewater. In the Chinese patent "An integrated sewage treatment device and method for highway service areas" with publication number CN113860633A, an iron-carbon-based composite biological carrier with a carbon source function is added, and the total nitrogen in the effluent is reduced to below the Class A standard of the "Pollutant Discharge Standard for Urban Sewage Treatment Plants" (GB 18918-2002) when the carbon-nitrogen ratio is about 5.2. At the same time, the technology uses a membrane bioreactor to improve the effluent water quality, which increases the operating cost. Moreover, for highway service area wastewater with a COD / TN of only 1.63-1.71 and an average value of 1.68, this technology cannot make the effluent total nitrogen meet the standard.

[0007] Therefore, there is an urgent need for a highway service area wastewater treatment technology that can treat highway service area wastewater with extremely low carbon-nitrogen ratio and has low operating cost, low sludge production, and good total nitrogen removal effect. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a highway service area wastewater treatment device based on the AOOA-MBBR process, which solves the problems that the existing extremely low carbon-nitrogen ratio highway service wastewater treatment requires an external carbon source / electron donor, has high operating costs, poor denitrification effect, and high sludge production.

[0009] In order to solve the above technical problems, the technical solution of the present invention is: a highway service area wastewater treatment device based on AOOA-MBBR process, comprising a first anoxic tank, a first aerobic tank, a second aerobic tank and a second anoxic tank connected in sequence; wherein,

[0010] The first anoxic tank, the first aerobic tank, the second aerobic tank and the second anoxic tank are respectively filled with MBBR fillers, and the volume of the filled MBBR fillers is taken as the effective volume;

[0011] The first aerobic pool and the second aerobic pool are respectively provided with an aeration device, the aeration device in the first aerobic pool is configured to make the dissolved oxygen concentration in the first aerobic pool 0.3-0.5 mg / L, and the aeration device in the second aerobic pool is configured to make the dissolved oxygen concentration in the second aerobic pool 2.0-2.5 mg / L;

[0012] The first anoxic tank is used for inoculating hydrolytic bacteria and denitrifying bacteria; the first aerobic tank is used for inoculating hydrolytic bacteria, nitrifying bacteria and denitrifying bacteria; the second aerobic tank is used for inoculating nitrifying bacteria, and the second anoxic tank is used for inoculating hydrolytic bacteria and denitrifying bacteria;

[0013] The second aerobic tank is connected to the first anoxic tank through a reflux pipe, and the reflux pipe is equipped with a reflux power component.

[0014] Furthermore, a sewage inlet is provided at the upper end of the first anoxic tank, and the lower end is connected to the lower end of the first aerobic tank; the upper end of the first aerobic tank is connected to the upper end of the second aerobic tank; the lower end of the second aerobic tank is connected to the lower end of the second anoxic tank; and a clean water outlet is provided at the upper end of the second anoxic tank.

[0015] Furthermore, the highway service area wastewater treatment device based on the AOOA-MBBR process also includes an inlet pipe, which is connected to the sewage inlet and is equipped with a peristaltic pump for providing inlet power.

[0016] Furthermore, the diameter of the MBBR filler is 10 mm and the specific surface area is 60 m 2 / m 3 .

[0017] The present invention also relates to a highway service area wastewater treatment method of a highway service area wastewater treatment device based on an AOOA-MBBR process, comprising:

[0018] The wastewater from the highway service area flows through the first anoxic pool, the first aerobic pool, the second aerobic pool and the second anoxic pool in sequence;

[0019] Inoculate hydrolytic bacteria and denitrifying bacteria in the first anoxic tank; inoculate hydrolytic bacteria, nitrifying bacteria and denitrifying bacteria in the first aerobic tank; inoculate nitrifying bacteria in the second aerobic tank, and inoculate hydrolytic bacteria and denitrifying bacteria in the second anoxic tank; 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; the nitrification liquid reflux ratio is 200%, and it refluxes from the second aerobic tank to the first anoxic tank;

[0020] After the water output has been running stably for the preset time, the hydraulic retention time will be gradually shortened to 36h and 24h, entering the stable stage.

[0021] Furthermore, the COD / TN of highway service area wastewater is 1.63-1.71.

[0022] Further, during the process of inoculating the flora:

[0023] In the first anoxic tank, hydrolytic bacteria were inoculated once every 10 days, 200 mL each time, the bacterial solution concentration was 3-5 g / L, and a total of 8 inoculations; denitrifying bacteria were inoculated once every 5 days, 300 mL each time, the bacterial solution concentration was 8-10 g / L, and a total of 4 inoculations;

[0024] In the first aerobic pool, hydrolytic bacteria were inoculated once every 10 days, 150 mL each time, the bacterial solution concentration was 3-5 g / L, and the inoculation was performed 8 times; nitrifying bacteria and denitrifying bacteria were inoculated once every 5 days, 100 mL each time, the bacterial solution concentration was 8-10 g / L, and the inoculation was performed 4 times respectively;

[0025] In the second aerobic pool, nitrifying bacteria were inoculated once every 5 days, 400 mL each time, with a bacterial solution concentration of 8-10 g / L, and inoculated 4 times;

[0026] In the second anoxic tank, hydrolytic bacteria were inoculated once every 10 days, 100 mL each time, the bacterial solution concentration was 3-5 g / L, and the inoculation was 8 times; denitrifying bacteria were inoculated once every 5 days, 100 mL each time, the bacterial solution concentration was 8-10 g / L, and the inoculation was 4 times.

[0027] Furthermore, at the initial start-up of the highway service area wastewater treatment device based on the AOOA-MBBR process, the temperature was 30-31°C and the pH was 7.8-8.2;

[0028] After 30 days, the temperature dropped to 25-27°C and the pH remained unchanged.

[0029] After adopting the above technical solution, the present invention has the following beneficial effects:

[0030] (1) Good total nitrogen removal effect: When treating highway service area wastewater with extremely low carbon-nitrogen ratio (average COD / TN of 1.68), the total nitrogen was reduced from about 150 mg / L to 14.05 mg / L when the hydraulic retention time was 24 hours, and the removal rate was 90.68%. The total nitrogen in the effluent reached the Class A emission standard of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB18918-2002).

[0031] (2) Extremely low sludge production: The present invention uses most of the sludge as a carbon source after hydrolysis. Therefore, the sludge yield coefficient in the system of the present invention is only 0.028, which is much lower than the sludge yield coefficient (0.72-0.86) produced by conventional denitrification processes, significantly reducing the cost of sludge treatment.

[0032] (3) Solving the problem of insufficient carbon source during denitrification: The present invention uses most of the sludge as a carbon source after hydrolysis, and at the same time uses the difficult-to-degrade organic matter in the influent as a carbon source after hydrolysis, solving the problem of insufficient carbon source during denitrification. Theoretically, 2.86 mg COD is required to reduce 1 mg of nitrate nitrogen to nitrogen gas, and in practice, 4-5 mg COD is usually consumed; the present invention actually consumes only 1.80 mg COD to remove 1 mg of total nitrogen.

[0033] (4) Low operating cost: The present invention does not require the addition of an external carbon source / electron donor, and achieves efficient denitrification of highway service area wastewater with an extremely low carbon-nitrogen ratio (COD / TN average value of 1.68), significantly reducing operating costs. The dissolved oxygen in the first aerobic tank is controlled at 0.3-0.5 mg / L. The low dissolved oxygen concentration is conducive to improving the mass transfer efficiency of oxygen during aeration, thereby reducing the aeration volume and reducing operating costs.

[0034] (5) No secondary pollution: The present invention does not introduce any chemical agents when treating wastewater from highway service areas, and significantly reduces sludge production, so no secondary pollution is generated.

[0035] In summary, the present invention effectively solves the problem that the wastewater treatment of low carbon-nitrogen ratio (COD / TN average value is 1.68) in highway service areas requires the addition of electron donors (such as carbon sources), high operating costs, secondary pollution, and poor total nitrogen removal effect, and achieves low-cost and efficient removal of total nitrogen. After the sewage is treated by the A00A-MBBR process, it can meet the total nitrogen ≤15mg / L required by the Class A emission standard of the "Pollutant Discharge Standard for Urban Sewage Treatment Plants" (GB18918-2002). It has high application value and is conducive to promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of a highway service area wastewater treatment device based on the AOOA-MBBR process of the present invention;

[0037] Figure 2 This is a diagram showing the removal effect of COD during treatment in an embodiment of the present invention;

[0038] Figure 3 This is a diagram showing the effect of removing ammonia nitrogen during treatment in an embodiment of the present invention;

[0039] Figure 4 This is a diagram showing the effect of removing nitrate nitrogen during treatment in an embodiment of the present invention;

[0040] Figure 5 This is a diagram showing the effect of removing nitrite nitrogen during treatment in an embodiment of the present invention;

[0041] Figure 6 This is a diagram showing the effect of total nitrogen removal during treatment in an embodiment of the present invention;

[0042] Figure 7 This is a microbial detection diagram of the highway service area wastewater treatment device based on the AOOA-MBBR process in the stable stage of the present invention;

[0043] In the figure, 1, the first anoxic tank; 2, the first aerobic tank; 3, the second aerobic tank; 4, the second anoxic tank; 5, MBBR filler; 6, aeration device; 7, return pipe; 8, return power assembly; 9, inlet pipe. DETAILED DESCRIPTION

[0044] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0045] like Figure 1 As shown, a highway service area wastewater treatment device based on AOOA-MBBR process includes a first anoxic tank 1, a first aerobic tank 2, a second aerobic tank 3 and a second anoxic tank 4 which are connected in sequence; wherein,

[0046] The first anoxic tank 1, the first aerobic tank 2, the second aerobic tank 3 and the second anoxic tank 4 are respectively filled with MBBR fillers 5, and the volume of the filled MBBR fillers 5 is taken as the effective volume;

[0047] The first aerobic pool 2 and the second aerobic pool 3 are respectively provided with an aeration device 6. The aeration device 6 in the first aerobic pool 2 is configured to make the dissolved oxygen concentration in the first aerobic pool 2 to be 0.3-0.5 mg / L, and the aeration device 6 in the second aerobic pool 3 is configured to make the dissolved oxygen concentration in the second aerobic pool 3 to be 2.0-2.5 mg / L.

[0048] The first anoxic tank 1 is used for inoculating hydrolytic bacteria and denitrifying bacteria; the first aerobic tank 2 is used for inoculating hydrolytic bacteria, nitrifying bacteria and denitrifying bacteria; the second aerobic tank 3 is used for inoculating nitrifying bacteria, and the second anoxic tank 4 is used for inoculating hydrolytic bacteria and denitrifying bacteria;

[0049] The second aerobic pool 3 is connected to the first anoxic pool 1 via a reflux pipe 7 , and the reflux pipe 7 is provided with a reflux power assembly 8 .

[0050] In this embodiment, if Figure 1 As shown, the upper end of the first anoxic tank 1 is provided with a sewage inlet, and the lower end is connected to the lower end of the first aerobic tank 2; the upper end of the first aerobic tank 2 is connected to the upper end of the second aerobic tank 3; the lower end of the second aerobic tank 3 is connected to the lower end of the second anoxic tank 4; the upper end of the second anoxic tank 4 is provided with a clean water outlet.

[0051] In this way, the wastewater can be fully treated in each pool.

[0052] In this embodiment, if Figure 1 As shown, the highway service area wastewater treatment device based on the AOOA-MBBR process also includes an inlet pipe 9, which is connected to the sewage inlet and is equipped with a peristaltic pump for providing inlet power.

[0053] The following is a detailed introduction to the sewage treatment method of the highway service area wastewater treatment device based on the AOOA-MBBR process involved in the above embodiment with respect to a specific embodiment.

[0054] 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 10.8L, 8.1L, 8.1L and 5.4L respectively. Fillers are added to the above tanks, and the filler addition amounts are 10.8L, 8.1L, 8.1L and 5.4L respectively, that is, all microorganisms are attached to the fillers, which is conducive to the growth of microorganisms with long generation cycles. The diameter of the MBBR filler 5 is 10mm, and the specific surface area is 60m 2 / m 3 The filler only provides a carrier for the growth of microorganisms and cannot be decomposed by microorganisms.

[0055] The COD, ammonia nitrogen, total nitrogen and total phosphorus concentrations of the simulated highway service area wastewater are approximately 250 mg / L, 140 mg / L, 150 mg / L and 5.0 mg / L respectively. The highway service area wastewater treatment method includes:

[0056] Start-up phase: simulated highway service area wastewater flows through the first anoxic pool 1, the first aerobic pool 2, the second aerobic pool 3 and the second anoxic pool in sequence. The COD / TN of the highway service area wastewater is 1.63-1.71, with an average value of 1.68;

[0057] Hydrolytic bacteria and denitrifying bacteria are inoculated in the first anoxic pool 1. In the first anoxic pool 1, hydrolytic bacteria are inoculated once every 10 days, 200 mL each time, the bacterial solution concentration is 3-5 g / L, and a total of 8 inoculations; denitrifying bacteria are inoculated once every 5 days, 300 mL each time, the bacterial solution concentration is 8-10 g / L, and a total of 4 inoculations;

[0058] Inoculate hydrolytic bacteria, nitrifying bacteria and denitrifying bacteria in the first aerobic pool 2. Inoculate hydrolytic bacteria once every 10 days, 150 mL each time, the bacterial solution concentration is 3-5 g / L, and inoculate 8 times; inoculate nitrifying bacteria and denitrifying bacteria once every 5 days, 100 mL each time, the bacterial solution concentration is 8-10 g / L, and inoculate 4 times respectively;

[0059] Inoculate nitrifying bacteria in the second aerobic pool 3, once every 5 days, 400 mL each time, with a bacterial solution concentration of 8-10 g / L, and inoculate 4 times;

[0060] Inoculate hydrolytic bacteria and denitrifying bacteria in the second anoxic pool 4. Inoculate hydrolytic bacteria once every 10 days, 100 mL each time, the bacterial solution concentration is 3-5 g / L, and inoculate 8 times; inoculate denitrifying bacteria once every 5 days, 100 mL each time, the bacterial solution concentration is 8-10 g / L, and inoculate 4 times;

[0061] The dissolved oxygen concentration in the first aerobic pool 2 is 0.3-0.5 mg / L; the dissolved oxygen concentration in the second aerobic pool 3 is 2.0-2.5 mg / L;

[0062] In order to allow the functional bacteria to better attach and grow on the filler, domesticate and cultivate the functional bacteria, the temperature was initially controlled at 30-31°C and the pH was controlled between 7.8-8.2; after 30 days, the temperature dropped to 25-27°C and the pH remained unchanged. The dissolved oxygen concentrations in the first aerobic pool 2 and the second aerobic pool 3 were 0.3-0.5 mg / L and 2.0-2.5 mg / L, respectively, the hydraulic retention time was 48 hours, and the nitrification liquid reflux ratio was 200%, which was returned from the second aerobic pool 3 to the first anoxic pool 1. After the effluent has been running stably for 15 days, the hydraulic retention time is shortened to 36 hours. After the effluent is stable again, the hydraulic retention time is shortened to 24 hours. After the effluent is stable again, it enters the stable stage.

[0063] exist Figures 2 to 6 According to the data, the stable stage of effluent with a hydraulic retention time of 48 hours is from the 34th to the 48th day, the stable stage with a hydraulic retention time of 36 hours is from the 84th to the 98th day, and the stable stage with a hydraulic retention time of 24 hours is from the 120th to the 134th day.

[0064] The return ratio refers to the ratio of the flow rate of the nitrification liquid returned from the second aerobic tank 3 to the first anoxic tank 1 to the flow rate of the highway service area wastewater entering the first anoxic tank 1 from the sewage inlet of the first anoxic tank 1. The effluent stability means that the COD, ammonia nitrogen, total nitrogen and total phosphorus concentrations in the water do not fluctuate by more than 10% relative to the average concentrations of COD, ammonia nitrogen, total nitrogen and total phosphorus in 13 consecutive days.

[0065] In the stable stage (120th to 134th day), the hydraulic retention time is 24 hours, the effluent COD ranges from 10.62-13.04 mg / L, and the average concentration is 11.87 mg / L; the removal efficiency is 94.84%-95.84%, and the average removal efficiency is 95.34%; the effluent total nitrogen ranges from 14.05-14.77 mg / L, and the average concentration is 14.33 mg / L; the removal efficiency is 90.25%-90.64%, and the average removal rate is 90.49%. The effluent COD and total nitrogen have reached the requirements of the Class A emission standard of the "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" (GB18918-2002) (COD≤50mg / L, total nitrogen≤15mg / L).

[0066] in, Figure 2 This is a diagram showing the removal effect of COD during treatment in an embodiment of the present invention; Figure 3 This is a diagram showing the effect of removing ammonia nitrogen during treatment in an embodiment of the present invention; Figure 4 This is a diagram showing the effect of removing nitrate nitrogen during treatment in an embodiment of the present invention; Figure 5 This is a diagram showing the effect of removing nitrite nitrogen during treatment in an embodiment of the present invention; Figure 6 This is a diagram showing the effect of total nitrogen removal during treatment in an embodiment of the present invention; Figure 7 This is a microbial detection diagram of the highway service area wastewater treatment device based on the AOOA-MBBR process in the stable stage of the present invention.

[0067] The sewage treatment involved in the above-mentioned embodiment is introduced in detail from the principle aspect below.

[0068] In view of the extremely low carbon-nitrogen ratio (COD / TN average value of 1.68) of highway service wastewater, the present invention has developed a highway service area wastewater treatment device and method based on the AOOA-MBBR process. The influent in the first anoxic tank 1 and the nitrified liquid from the second aerobic tank 3 are mixed and flow through the MBBR filler 5 in the first anoxic tank 1. The denitrifying bacteria attached to the MBBR filler 5 use the organic matter in the influent to reduce the nitrate nitrogen carried in the nitrified liquid to nitrogen gas, thereby achieving denitrification. In the startup stage, the hydrolytic bacteria inoculated, cultured and domesticated in the first anoxic tank 1 are relatively efficient. Under the condition of severe lack of carbon source, the hydrolytic bacteria attached to the filler can hydrolyze the difficult-to-degrade organic matter in the influent into easily degradable organic matter, thereby providing a carbon source for denitrification. The COD concentration in the effluent of the first anoxic tank 1 has dropped to below 22 mg / L (the COD concentration range is 16.73 mg / L-21.60 mg / L), which can prove the above viewpoint. After the biofilm on the MBBR filler 5 in the first anoxic pool 1 falls off, it will settle on the bottom of the pool. The debris formed after the death of the microorganisms in the biofilm will be adsorbed by the highly active biofilm on the MBBR filler 5, and then hydrolyzed by the hydrolytic bacteria to provide a carbon source for denitrification. The debris produced after the death of the microorganisms will be removed by the efficient hydrolytic bacteria and denitrifying bacteria, and will not cause an increase in COD. In addition, denitrifying bacteria can also use refractory organic matter as a carbon source for denitrification and denitrification.

[0069] In the first aerobic pool 2, by controlling the dissolved oxygen at 0.3-0.5 mg / L, an aerobic layer dominated by nitrifying bacteria is formed on the outer layer of the biofilm on the MBBR filler 5, and an anoxic layer dominated by hydrolytic bacteria and denitrifying bacteria is formed on the inner layer of the biofilm on the MBBR filler 5, achieving simultaneous nitrification and denitrification; in this pool, the total nitrogen is greatly reduced from 43.02 mg / L (41.10 mg / L-46.59 mg / L) to 25.12 mg / L (22.86 mg / L-27.93 mg / L), proving that the total nitrogen is removed by simultaneous nitrification and denitrification. However, COD only dropped from 19.44 mg / L (16.73 mg / L-21.60 mg / L) to 16.04 mg / L (14.38 mg / L-20.47 mg / L), and the carbon source consumption is very small. The nitrifying bacteria in the aerobic layer use dissolved oxygen to oxidize the ammonia nitrogen in the effluent of the first anoxic tank 1 to nitrite nitrogen or nitrate nitrogen, the hydrolytic bacteria in the anoxic layer hydrolyze the refractory organic matter and the debris after the death of microorganisms into easily degradable organic matter, and the denitrifying bacteria in the anoxic layer use the above hydrolysis products as carbon sources to reduce nitrite nitrogen and nitrate nitrogen to nitrogen gas. The present invention controls the nitrate nitrogen / nitrite nitrogen in the first aerobic tank 2 between 1.8-2.0 by controlling the nitrification liquid reflux ratio, the hydraulic retention time of the first anoxic tank 1, the dissolved oxygen of the first aerobic tank 2, the hydraulic retention time of the first aerobic tank 2, the temperature, pH, carbon source conditions, etc., thereby achieving a higher concentration of nitrite nitrogen accumulation. Oxidizing ammonia nitrogen to nitrite nitrogen can reduce the consumption of dissolved oxygen and reduce operating costs; reducing nitrite nitrogen to nitrogen can reduce the consumption of carbon sources and achieve efficient removal of total nitrogen using limited carbon sources.

[0070] The dissolved oxygen in the second aerobic pool 3 is controlled at 2.0-2.5 mg / L. The MBBR filler 5 is mainly composed of aerobic biofilms, and the biofilms are mainly composed of nitrifying bacteria. Therefore, the goal of the second aerobic pool 3 is to nitrify ammonia nitrogen to nitrite nitrogen and nitrate nitrogen. Nitrifying bacteria use dissolved oxygen to oxidize ammonia nitrogen and nitrite nitrogen in the effluent of the first aerobic pool 2 to nitrate nitrogen. Ammonia nitrogen has obviously dropped from 12.70 mg / L (11.17 mg / L-14.86 mg / L) to 7.75 mg / L (7.59 mg / L-7.98 mg / L). At the same time, there is a local anoxic zone in the second aerobic pool 3, which can denitrify nitrate nitrogen and nitrite nitrogen into nitrogen gas. The total nitrogen in this pool is slightly reduced from 25.12 mg / L (22.86 mg / L-27.93 mg / L) to 23.60 mg / L (22.55 mg / L-24.41 mg / L). In the second aerobic pool 3, dead microorganisms are also used as a carbon source.

[0071] In the second anoxic pool 4, hydrolytic bacteria and denitrifying bacteria are also inoculated, cultured, and domesticated during the startup phase. The hydrolytic bacteria attached to the MBBR filler 5 can hydrolyze the difficult-to-degrade organic matter in the effluent of the second aerobic pool 3 into easily degradable organic matter, thereby providing a carbon source for denitrification. The COD in the second anoxic pool 4 slightly dropped from 13.62 mg / L (15.52 mg / L-11.40 mg / L) to 11.87 mg / L (10.62 mg / L-13.04 mg / L), but the total nitrogen dropped significantly from 23.60 mg / L (22.55 mg / L-24.41 mg / L) to 14.33 mg / L (14.05 mg / L-14.77 mg / L). The biofilm on the MBBR filler 5 will fall off and settle at the bottom of the pool. The debris formed after the death of the microorganisms in the biofilm will be adsorbed by the highly active biofilm on the MBBR filler 5, and then further hydrolyzed to provide a carbon source for denitrification. In addition, denitrifying bacteria can also use difficult-to-degrade organic matter as a carbon source for denitrification.

[0072] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A highway service area wastewater treatment device based on AOOA-MBBR process, characterized in that: It comprises a first anoxic pool (1), a first aerobic pool (2), a second aerobic pool (3) and a second anoxic pool (4) which are connected in sequence; wherein: The first anoxic tank (1), the first aerobic tank (2), the second aerobic tank (3) and the second anoxic tank (4) are respectively filled with MBBR fillers (5), and the volume of the filled MBBR fillers (5) is used as the effective volume; The first aerobic tank (2) and the second aerobic tank (3) are respectively provided with an aeration device (6), the aeration device (6) in the first aerobic tank (2) is configured to make the dissolved oxygen concentration in the first aerobic tank (2) be 0.3-0.5 mg / L, and the aeration device (6) in the second aerobic tank (3) is configured to make the dissolved oxygen concentration in the second aerobic tank (3) be 2.0-2.5 mg / L; The first anoxic tank (1) is used for inoculating hydrolytic bacteria and denitrifying bacteria; the first aerobic tank (2) is used for inoculating hydrolytic bacteria, nitrifying bacteria and denitrifying bacteria; the second aerobic tank (3) is used for inoculating nitrifying bacteria, and the second anoxic tank (4) is used for inoculating hydrolytic bacteria and denitrifying bacteria; The second aerobic pool (3) is connected to the first anoxic pool (1) via a return pipe (7), and the return pipe (7) is provided with a return power assembly (8).

2. The highway service area wastewater treatment device based on the AOOA-MBBR process according to claim 1 is characterized in that: The upper end of the first anoxic tank (1) is provided with a sewage inlet, and the lower end is connected to the lower end of the first aerobic tank (2); the upper end of the first aerobic tank (2) is connected to the upper end of the second aerobic tank (3); the lower end of the second aerobic tank (3) is connected to the lower end of the second anoxic tank (4); the upper end of the second anoxic tank (4) is provided with a clean water outlet.

3. The highway service area wastewater treatment device based on the AOOA-MBBR process according to claim 1 is characterized in that: It also comprises an inlet pipe (9), the inlet pipe (9) is connected to the sewage inlet, and the inlet pipe (9) is equipped with a peristaltic pump for providing inlet flow power.

4. The highway service area wastewater treatment device based on the AOOA-MBBR process according to claim 1 is characterized in that: The MBBR filler (5) has a diameter of 10 mm and a specific surface area of ​​60 m 2 / m 3 .

5. A method for treating wastewater in a highway service area based on the highway service area wastewater treatment device based on the AOOA-MBBR process according to any one of claims 1 to 4, characterized in that: include: The wastewater from the expressway service area flows through the first anoxic pool (1), the first aerobic pool (2), the second aerobic pool (3) and the second anoxic pool in sequence; wherein: 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 nitrification liquid reflux ratio is 200%, and it refluxes from the second aerobic tank (3) to the first anoxic tank (1); After the water output has been running stably for the preset time, the hydraulic retention time will be gradually shortened to 36h and 24h, entering the stable stage.

6. The highway service area wastewater treatment method according to claim 5, characterized in that: The COD / TN of wastewater from highway service areas is 1.63-1.

71.

7. The highway service area wastewater treatment method according to claim 6, characterized in that: During the inoculation process: In the first anoxic tank (1), hydrolytic bacteria are inoculated once every 10 days, 200 mL each time, the bacterial solution concentration is 3-5 g / L, and a total of 8 inoculations are made; denitrifying bacteria are inoculated once every 5 days, 300 mL each time, the bacterial solution concentration is 8-10 g / L, and a total of 4 inoculations are made; In the first aerobic pool (2), hydrolytic bacteria are inoculated once every 10 days, 150 mL each time, the bacterial solution concentration is 3-5 g / L, and the inoculation is performed 8 times; nitrifying bacteria and denitrifying bacteria are inoculated once every 5 days, 100 mL each time, the bacterial solution concentration is 8-10 g / L, and the inoculation is performed 4 times; In the second aerobic pool (3), nitrifying bacteria are inoculated once every 5 days, 400 mL each time, and the concentration of the bacterial solution is 8-10 g / L, and the inoculation is performed 4 times; In the second anoxic tank (4), hydrolytic bacteria are inoculated once every 10 days, 100 mL each time, the bacterial solution concentration is 3-5 g / L, and the inoculation is performed 8 times; denitrifying bacteria are inoculated once every 5 days, 100 mL each time, the bacterial solution concentration is 8-10 g / L, and the inoculation is performed 4 times.

8. The highway service area wastewater treatment method according to claim 5, characterized in that: At the initial start-up of the highway service area wastewater treatment device based on the AOOA-MBBR process, the temperature was 30-31°C and the pH was 7.8-8.2; After 30 days, the temperature dropped to 25-27°C and the pH remained unchanged.

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