An evaluation method for a pure membrane MBBR system

Abstract

The application relates to an evaluation method of a pure membrane MBBR system, which evaluates the feasibility of the pure membrane MBBR process by adjusting the operation conditions of a pilot plant and collecting the data of actual engineering operation, and the evaluation parameters include the evaluation of the filling ratio of the filler, the thickness of the biological membrane of the filler, the ratio of the suspended sludge and the filler, the abundance of the bacterial flora on the filler, the membrane formation rate, the impact resistance, the biological denitrification and phosphorus removal efficiency, the blocking of the filler screen, the maximum instantaneous dissolved oxygen of the aeration system and the stirring density of the stirring system of the anoxic tank; the performance of the pure membrane MBBR system is divided according to the measured different indexes. The method comprehensively evaluates the performance of the pure membrane MBBR process, and provides a technical means for the application effect evaluation of the later engineering.

Description

TECHNICAL FIELD

[0001] The application relates to an evaluation method of a pure membrane MBBR system and belongs to the technical field of sewage treatment equipment detection. BACKGROUND

[0002] The moving bed biofilm reactor (MBBR) MBBR technology is a new type of efficient sewage treatment technology. The pure membrane MBBR technology has been applied in Norway and Sweden as early as the 1990s. In China, the technology has been popularized and applied since 2020, but there are few actual engineering cases. Simply relying on detection of whether the effluent meets the standard cannot measure the technical advantages of the process. There is no related evaluation system in China to conduct detailed technical evaluation and judgment, and it is not clear whether the quality is good or bad.

[0003] At present, the evaluation of the pure membrane MBBR technology is mostly to analyze and judge the biofilm formation of the filler from the perspective of microbiology, and to report the effluent quality from the engineering perspective. There is no complete evaluation system to conduct all-round evaluation and judgment on the feasibility, and it is still blank in China. SUMMARY

[0004] (I) Technical problems to be solved

[0005] In order to solve the above problems in the prior art, the application provides an evaluation method of a pure membrane MBBR system, which provides a basis for the evaluation of the pure membrane MBBR technology.

[0006] (II) Technical scheme

[0007] In order to achieve the above purpose, the main technical scheme adopted by the application comprises:

[0008] An evaluation method of a pure membrane MBBR system, which adjusts the operation conditions of a pilot plant and collects actual engineering operation data to evaluate the feasibility of the pure membrane MBBR process. The evaluation parameters include the evaluation of the filler filling ratio, the filler biofilm thickness, the ratio of the filler biofilm and the suspended sludge, the abundance of the bacterial community on the filler, the biofilm formation rate, the impact resistance, the biological denitrification and phosphorus removal efficiency, the filler blocking of the screen, the maximum instantaneous dissolved oxygen of the aeration system and the stirring density of the anoxic tank stirring system.

[0009] The evaluation results show that when the filler filling ratio is ≥50%, the effective biological membrane thickness of the filler is ≥100 μm, the ratio of filler biofilm and suspended sludge is ≥16:1, the abundance of bacterial community on the filler is AOB≥1%, NOB≥1%, DNB≥14%, the biofilm formation rate is <1 month, the impact resistance is water impact≥1.5, the water quality impact is≥1.3, the biological denitrification and phosphorus removal efficiency is TN≥70%, TP≥60%, the liquid level difference before and after the filler screen blockage is <50 mm, the maximum instantaneous dissolved oxygen of the aeration system is <6 ppm, and the stirring density of the anoxic tank stirring system is <15 w / m 3 is rated as A level;

[0010] When the filler filling ratio is <50%, the effective biological membrane thickness of the filler is <100 μm, the ratio of filler biofilm and suspended sludge is <16:1, the abundance of bacterial community on the filler is AOB<1%, NOB<1%, DNB<14%, the biofilm formation rate is ≥1 month, the impact resistance is water impact<1.5, the water quality impact is <1.3, the biological denitrification and phosphorus removal efficiency is TN<70%, TP<60%, the liquid level difference before and after the filler screen blockage is ≥50 mm, the maximum instantaneous dissolved oxygen of the aeration system is ≥6 ppm, and the stirring density of the anoxic tank stirring system is ≥15 w / m 3 is rated as B level.

[0011] The evaluation method described above, preferably, the filler filling ratio is for the pure membrane MBBR pool of an actual engineering case, 1L of filler carrier and mixed liquid of suspended sludge are selected, the filler carrier and suspended sludge are separated by using a large-aperture sieve, X of biofilm carriers are selected (the bulk volume is measured as VL), and the filler filling ratio is calculated as VL / 1L=V.

[0012] The evaluation method described above, preferably, the filler biofilm thickness is measured by selecting the biofilm carrier of the pure membrane MBBR of an actual engineering case, removing the suspended activated sludge in the pores of the carrier by washing with distilled water, placing the biofilm carrier in water, and observing under a microscope, randomly selecting multiple fields to measure the thickness, taking pictures, and measuring the thickness at multiple points to obtain an average value.

[0013] The evaluation method described above, preferably, the ratio of filler biofilm and suspended sludge is for the pure membrane MBBR pool of an actual engineering case, 1L of filler carrier and mixed liquid of suspended sludge are selected, the filler carrier and suspended sludge are separated by using a large-aperture sieve; wherein the mixed liquid of suspended sludge is measured by using ordinary activated sludge method to obtain MLSS1 (mixed liquid suspended solid concentration) and MLVSS1 (mixed liquid volatile suspended solid concentration);

[0014] For biofilm carriers, after carefully washing away the suspended activated sludge in the pores of the carrier with distilled water, the biofilm on the surface of the carrier is completely peeled off. The carrier is then dried in a 105℃ forced-air drying oven to constant weight, cooled, and weighed. Next, it is ignited in a 600℃ muffle furnace to constant weight, cooled, and weighed. The MLSS2 and MLVSS2 are calculated. The ratio of MLSS2 of the carrier biofilm to MLSS1 of the suspended sludge is the MLSS ratio of the biofilm on the packing material and the suspended sludge. The ratio of MLVSS2 of the carrier biofilm to MLVSS1 of the suspended sludge is the MLVSS ratio of the biofilm on the packing material and the suspended sludge.

[0015] The evaluation method described above, preferably, involves the following procedure for assessing the abundance of microbial communities on the packing material: Pure membrane MBBR vector samples from actual engineering cases are taken, and microbial genomic DNA is extracted using a high-throughput sequencing kit. The integrity of the extracted genome is detected by 2% agarose gel electrophoresis. The Soil DNA Kit was used to determine the concentration of genomic DNA. Upstream primer 338F (5'-ACTCCTACGGGAGGCAGCAG-3') and downstream primer 806R (5'-GGACTACHVGGGTWTCTAAT-3') were used to amplify the V3-V4 variable region of the 16S rRNA gene by PCR. The PCR products were recovered using a DNA gel recovery kit, and the recovered DNA was precisely quantified using a DNA detection kit. The DNA was then sequenced after being mixed in a 1:1 ratio. High-throughput sequencing of the samples was performed using the Illumina Miseq sequencing platform, and the abundance of denitrifying bacteria was calculated.

[0016] As described above, the evaluation method preferably involves using activated sludge from the aeration tank of a wastewater treatment plant as inoculum sludge, which is then introduced into a pure membrane MBBR reactor and aerated for 24 hours. The supernatant is then drained, and wastewater influent is introduced for testing. The MBBR reactor is then subjected to conventional aeration and stirring for one month. Daily observations are required to monitor biofilm formation on the packing material, including taking photos and recording the data, as well as measuring the amount of biofilm on the packing material. An MLSS curve is then plotted to fit the biofilm formation rate.

[0017] The evaluation method described above preferably uses a pilot-scale device to determine the shock resistance capability. This pilot-scale device is specifically designed for a pure membrane MBBR system. After the pure membrane MBBR reactor is operating normally and stably, the influent flow rate is adjusted using a water pump and flow meter. At influent flow rate increases of 20%, 30%, 50%, 70%, and 100%, the influent and effluent COD, TN, NH3-N, TP, and MLSS and SS levels within the reactor are measured daily. The treatment effect is compared and analyzed, while simultaneously observing and measuring changes in biofilm thickness.

[0018] The pilot device adopts sewage with different concentration gradients while keeping the water inflow unchanged. When the indexes of COD, NH3-N and TN are 1.2 times, 1.3 times, 1.5 times, 1.7 times and 2.0 times of the indexes of the original water sample, the indexes of COD, TN, NH3-N and TP of the inflow and outflow water are measured every day, and the MLSS (mixed liquor suspended solid concentration) and SS (suspended matter) in the reactor are observed, so as to compare and analyze the treatment effect, and observe and measure the change of the biofilm thickness.

[0019] According to the evaluation method, the removal rates of TN and TP of the pure membrane MBBR unit are calculated by collecting the indexes of the inflow and outflow water of the pure membrane MBBR unit in the pilot device and the actual engineering case.

[0020] The TP and TN indexes of the pure membrane MBBR unit mixed for 24 hours on the same day are collected. 进 进、 出 出 The nitrogen and phosphorus removal capacities are calculated as (TP 进 -TP 出 ) / TP 进 and (TN 进 -TN 出 ) / TN 进 .

[0021] According to the evaluation method, the water level difference on both sides of the filler screen in the actual engineering case is observed.

[0022] The evaluation method of the aeration system is to collect the dissolved oxygen values of the water inflow, the middle and the end of the aerobic section of the pure membrane MBBR tank in the actual engineering case.

[0023] The evaluation of the anoxic tank stirring system is to collect the number and power of the mechanical stirring of the anoxic tank in the actual engineering case, and to calculate the stirring density of the anoxic tank.

[0024] ​​​The evaluation method as described above, preferably, the pilot device comprises, in sequence, a raw water pool, a front anoxic pool, an anoxic / aerobic adjustable pool, a front aerobic pool, an oxygen-consuming pool, a rear anoxic pool, a rear aerobic pool, a sedimentation pool and a device room, each pool is divided by a steel plate, and a water passing hole is left, the water passing hole is arranged in an upper-in and lower-out staggered outflow mode, and a filler blocking net is arranged at the water passing hole; the front anoxic pool, the anoxic / aerobic adjustable pool, the front aerobic pool, the oxygen-consuming pool, the rear anoxic pool and the rear aerobic pool are all provided with pure membrane MBBR fillers; the raw water pool, the front anoxic pool, the anoxic / aerobic adjustable pool, the oxygen-consuming pool and the rear anoxic pool are all provided with agitators; the anoxic / aerobic adjustable pool, the front aerobic pool and the rear aerobic pool are all provided with aeration systems; the sedimentation pool is provided with an inclined pipe to strengthen the sedimentation effect; the device room is provided with a dosing system, a pump, a fan and a control system, the dosing system realizes dosing in each pool through a connecting pipeline; and the pump and the fan are both connected with each pool through pipelines.

[0025] (III) Beneficial Effects

[0026] The beneficial effects of the present application are:

[0027] The evaluation method of the pure membrane MBBR system provided by the present application verifies the pure membrane MBBR process by adjusting the operation conditions of the pilot device and collecting data of actual engineering cases, obtains ten indexes of the filler filling ratio, the effective biological membrane thickness of the filler, the ratio of the filler biofilm and suspended sludge, the abundance of the bacterial flora on the filler, the biofilm formation rate, the impact resistance, the biological denitrification and phosphorus removal efficiency, the filler blocking net blockage, the aeration system and the anoxic pool stirring system, comprehensively evaluates the performance of the pure membrane MBBR process, and provides a technical means for the application effect evaluation of the later engineering. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a schematic diagram of the MBBR suspended carrier;

[0029] Figure 2 It is a micrograph of the suspended carrier;

[0030] Figure 3 It is a schematic diagram of the bacterial genus distribution;

[0031] Figure 4 It is a plane schematic diagram of the pilot device;

[0032] Figure 5 It is a vertical sectional view of the pilot device.

[0033] KEY

[0034] 1: raw water pool; 2: front anoxic pool; 3: anoxic / aerobic adjustable pool; 4: front aerobic pool; 5: oxygen-consuming pool; 6: rear anoxic pool; 7: rear aerobic pool; 8: sedimentation pool; 9: device room. DETAILED DESCRIPTION

[0035] In order to better explain the present application, so as to be understood, the present application is described in detail below by specific embodiments in combination with the drawings.

[0036] Example 1

[0037] An evaluation method of a pure membrane MBBR system, which adjusts the operation condition of a pilot plant and collects data of actual engineering operation to evaluate the feasibility of the pure membrane MBBR process, includes the following aspects:

[0038] Table 1

[0039]

[0040]

[0041] Now, the evaluation method of the above evaluation content is introduced in detail:

[0042] 1. Evaluation of filler filling ratio

[0043] Tool: large aperture sieve.

[0044] Method: In the pure membrane MBBR tank of the actual engineering case, 1L of filler carrier and suspended sludge mixed liquid are selected, the filler carrier and suspended sludge are separated by a large aperture sieve, X of the biofilm carriers are selected, the bulk volume V L is measured, and the filling ratio is calculated as V L / 1L=V.

[0045] 2. Evaluation of biofilm thickness of filler

[0046] Tool: industrial digital microscope; (or stereoscopic microscope)

[0047] Method: The biofilm carrier of the actual engineering case is selected, the suspended activated sludge in the carrier pores is removed after careful cleaning with distilled water, and then the biofilm carrier is placed in water and observed under the microscope. After setting the parameters, multiple fields are randomly selected for thickness measurement, photographing and multi-point thickness measurement. The suspended carrier of the pure membrane MBBR can be as shown in Figure 1 , and the suspended carrier micrograph can be as shown in Figure 2 .

[0048] 3. Proportion of filler biofilm and suspended sludge

[0049] Tool: oven; muffle furnace; sodium hydroxide; distilled water; volumetric flask; glass rod; balance; weighing paper; glass beaker; washing bottle.

[0050] Method: In the actual engineering case of pure membrane MBBR pool, 1L filler carrier and suspended sludge mixed liquid were selected, the filler carrier and suspended sludge were separated by using large aperture sieve, and the suspended sludge liquid was measured by using ordinary activated sludge method to obtain MLSS1 and MLVSS1;

[0051] The membrane carrier was carefully cleaned with distilled water to remove the suspended activated sludge in the carrier pores, and the biofilm on the surface of the carrier was completely stripped out and placed in a 105℃ air drying oven to dry to constant weight. After cooling, it was weighed again. Then it was placed in a 600℃ muffle furnace and burned to constant weight. After cooling, it was weighed again, and MLSS2 and MLVSS2 were calculated. Note:

[0052] (1) The experiment needs to be repeated more than 5 times, and the carriers at different positions are selected.

[0053] (2) The ratio of MLSS2 of the carrier biofilm to MLSS1 of the suspended sludge is the MLSS ratio of the filler membrane and the suspended sludge. The ratio of MLVSS2 of the carrier biofilm to MLVSS1 of the suspended sludge is the MLVSS ratio of the filler membrane and the suspended sludge.

[0054] 4. Evaluation of bacterial community abundance on filler

[0055] Take the pure membrane MBBR carrier sample of the actual engineering case, use high-throughput sequencing to extract microbial genomic DNA with the kit, detect the integrity of the extracted genome by 2% agarose gel electrophoresis, and use Soil DNA Kit DNA extraction kit to determine the mass concentration of genomic DNA, use upstream primer 338F (5'-ACTCCTACGGGAGGCAGCAG-3') and downstream primer 806R (5'-GGACTACHVGGGTWTCTAAT-3') carrying Barcode sequence to PCR amplify 16S rRNA gene V3-V4 variable region, and use DNA gel recovery kit to recover PCR product, use DNA detection kit to accurately quantify the recovered DNA, mix according to 1:1, and then sequence; high-throughput sequencing of samples is completed by Illumina Miseq sequencing platform, and the abundance of denitrifying bacteria community is calculated.

[0056] The bacteria with universal denitrification properties described in Berge's Bacterial Identification Manual and related literature are used as denitrifying bacteria, and their community abundance is calculated. The community abundance can be seen in Figure 3 .

[0057] 5. Evaluation of biofilm formation rate

[0058] Tools: 1 set of pure membrane MBBR pilot plant (its structure is as shown in Figure 4 and Figure 5As shown, the pilot plant is a carbon steel structure, which is provided with sequentially communicating raw water pool 1, front anoxic pool 2, anoxic / oxygen adjustable pool 3, front oxygen pool 4, oxygen depletion pool 5, rear anoxic pool 6, rear oxygen pool 7, sedimentation pool 8 and equipment room 9. The pools are divided by steel plates and have water passing holes, and the water passing adopts staggered outflow from top to bottom to prevent short flow.

[0059] The water flow sequence of the pilot plant is: water inlet-raw water pool-front anoxic pool-anoxic / oxygen adjustable pool-front oxygen pool-oxygen depletion pool-rear anoxic pool-rear oxygen pool-sedimentation pool-water outlet. The pure membrane MBBR fillers are arranged in the front anoxic pool, anoxic / oxygen adjustable pool, front oxygen pool, oxygen depletion pool, rear anoxic pool and rear oxygen pool, and the water passing holes between the pools are provided with filler blocking nets to prevent filler loss; the raw water pool, front anoxic pool, anoxic / oxygen adjustable pool, oxygen depletion pool and rear anoxic pool are provided with mixers; the anoxic / oxygen adjustable pool, front oxygen pool and rear oxygen pool are provided with aeration systems; the sedimentation pool is provided with an inclined pipe to enhance the sedimentation effect; the equipment room is provided with a dosing system, pumps, fans and a control system. The dosing system realizes dosing in each pool through connecting pipelines, such as adding flocculants in the sedimentation pool; the pumps and fans are connected with each pool by pipelines; the fans are connected with the aeration systems of the anoxic / oxygen adjustable pool, front oxygen pool, oxygen depletion pool, rear anoxic pool and rear oxygen pool; one set of DO instrument, COD detection instrument, TN detection instrument, NH3-N instrument, TP instrument and sludge concentration instrument; three sets of samplers, five beakers, one muffle furnace, one alcohol lamp, three boxes of filter paper, one test balance and sewage plant water inlet.

[0060] Method: The activated sludge in the aeration tank of a sewage plant is used as inoculated sludge and introduced into the pilot plant, and then the supernatant is discharged after 24 hours of incubation, and the sewage plant water is introduced for testing. The pure membrane MBBR pilot plant is subjected to conventional aeration (DO control refers to the actual engineering project) and stirring for one month. The formation of biofilm on the fillers is observed and photographed every day, and the amount of biofilm on the fillers is measured, and the MLSS change curve is drawn to fit the biofilm formation rate. The COD, TN, NH3-N, TP and other indicators of the inlet and outlet water in the reactor are measured once a day.

[0061] 6. Impact resistance evaluation

[0062] Tools: one set of pure membrane MBBR pilot plant (structure diagram as shown in Figure 4 , supporting fan, water pump, stirrer, filler, interception facility, etc.), one water inlet flow meter, two water inlet pumps with variable frequency adjustable flow, tap water and water pump, pipeline, water inlet dilution adjustment barrel, one set of DO instrument, COD detection instrument, TN detection instrument, NH3-N instrument, TP instrument and sludge concentration instrument, three sets of samplers, five beakers, one muffle furnace, one alcohol lamp, three boxes of filter paper and one test balance

[0063] Method: After the normal and stable operation of the pure membrane MBBR pilot plant, the water inflow is adjusted by the water pump and flow meter. When the water inflow increases by 20%, 30%, 50%, 70%, and 100%, respectively, the COD, TN, NH3-N, TP, and other indicators of the influent and effluent are measured every day, and the MLSS and SS in the reactor are observed and measured. The treatment effect is compared and analyzed, and the change of biofilm thickness is observed and measured.

[0064] The pilot plant keeps the water inflow unchanged, and takes different concentration gradient sewage (adding septic tank sewage or industrial wastewater), so that the COD, NH3-N, TN and other indicators of the influent are 1.2 times, 1.3 times, 1.5 times, 1.7 times, and 2.0 times of the original water sample indicators. Every day, the COD, TN, NH3-N, TP, and other indicators of the influent and effluent are measured, and the MLSS and SS in the reactor are observed and measured. The treatment effect is compared and analyzed, and the change of biofilm thickness is observed and measured.

[0065] 7. Evaluation of biological nitrogen and phosphorus removal efficiency

[0066] The TP and TN indicators of the influent and effluent of the pure membrane MBBR unit of the pilot plant and the actual engineering case are collected, and the TN and TP removal rates of the biochemical unit are calculated.

[0067] The TP and TN of the influent and effluent of the pure membrane MBBR mixed for 24 hours on the same day are measured and calculated. The nitrogen and phosphorus removal efficiency is calculated to evaluate the nitrogen and phosphorus removal capacity, which is calculated by (TP 进 -TP 出 ) / TP 进 , (TN 进 -TN 出 ) / TN 进 .

[0068] 8. Evaluation of filler screen blockage

[0069] The pure membrane MBBR process has a high filler filling ratio, and the water flow velocity near the reflux pump suction pipe of the mixed liquid will be high, which will cause the accumulation of fillers near the filler screen.

[0070] Tools: rope, bucket.

[0071] The following steps are used for evaluation:

[0072] 1. Observe the water level difference on both sides of the filler screen in the actual engineering case. If the filler accumulation is serious, it will cause pollution of the filler screen, increase the water loss, and increase the liquid level difference.

[0073] 2. Select the mixed liquid reflux pump suction pipe packing screen before, the aerobic section water inlet, the aerobic section three points in the middle part, with the same volume of water sample, statistics of the number of fillers in water sample for judging whether there is a phenomenon of filler accumulation.

[0074] 9. Aeration system evaluation

[0075] The essence of pure membrane MBBR process is biofilm method, plus the filling ratio of the filler is larger, to investigate whether the process will cause certain influence on the selection of aeration fan (including fan type, brand, air volume and air pressure).

[0076] Specifically, the following steps are taken to evaluate the collection of actual engineering cases. The dissolved oxygen values of the pure membrane MBBR tank aerobic section inlet, middle and end are collected.

[0077] 10. Evaluation of anoxic tank stirring system

[0078] For the evaluation of the flow pattern of the anoxic tank, the number and power of the mechanical stirring of the anoxic tank are collected, and the stirring density of the anoxic tank is calculated.

[0079] 2. The flow pattern of the anoxic tank is evaluated by establishing a hydraulic model of the anoxic tank.

[0080] According to the above evaluation method, the following Table 2 is obtained:

[0081] Table 2

[0082]

[0083] Among them, the evaluation results are within the scope of A level, and the operation effect and operation energy consumption are in better state.

[0084] The above is only the preferred embodiment of the present application, and is not other forms of the present application, any person skilled in the art can use the above disclosed technical content to change or modify as equivalent embodiment. But any simple modification, equivalent change and modification of the above embodiment without departing from the technical scheme of the present application, according to the technical essence of the present application, still belongs to the protection scope of the present application.

Claims

1. An evaluation method for a pure membrane MBBR system, characterized in that, The feasibility of the pure membrane MBBR process was evaluated by adjusting the operating conditions of the pilot plant and collecting data from actual engineering operations. The evaluation parameters included the packing ratio, packing biofilm thickness, ratio of biofilm to suspended sludge on the packing, abundance of microbial community on the packing, biofilm formation rate, shock resistance, biological nitrogen and phosphorus removal efficiency, packing screen blockage, maximum instantaneous dissolved oxygen in the aeration system, and stirring density of the anoxic tank mixing system. The evaluation results show that when the packing material filling ratio is ≥50%, the effective biofilm thickness is ≥100μm, the ratio of biofilm to suspended sludge is ≥16:1, and the abundance of bacteria on the packing material is AOB ≥1%, NOB ≥1%, and DNB ≥14%; the biofilm formation rate is <1 month, the shock resistance is water volume shock ≥1.5, the water quality shock ≥1.3, the biological nitrogen and phosphorus removal efficiency is TN ≥70%, and TP ≥60%; the liquid level difference before and after the packing material screen is blocked is <50mm, the maximum instantaneous dissolved oxygen in the aeration system is <6ppm, and the stirring density of the mixing system in the anoxic tank is <15w / m³, the optimal conditions for biofilm formation are met. 3 Rated as Grade A; When the packing material filling ratio is <50%, the effective biofilm thickness is <100μm, the ratio of biofilm to suspended sludge is <16:1, and the abundance of bacteria on the packing material is AOB <1%, NOB <1%, and DNB <14%; the biofilm formation rate is ≥1 month, the shock resistance is water volume shock <1.5, the water quality shock is <1.3, the biological nitrogen and phosphorus removal efficiency is TN <70%, and TP <60%; the liquid level difference before and after the packing material screen is blocked is ≥50mm, the maximum instantaneous dissolved oxygen in the aeration system is ≥6ppm, and the stirring density of the mixing system in the anoxic tank is ≥15w / m³. 3 Rated as Grade B.

2. The evaluation method as described in claim 1, characterized in that, The packing ratio is for a pure membrane MBBR tank in an actual engineering case. 1L of packing carrier and suspended sludge mixture is selected, and the packing carrier and suspended sludge are separated using a large-pore sieve. There are X biofilm carriers, and their stacked volume is measured as V. The packing ratio is V.

3. The evaluation method as described in claim 1, characterized in that, The thickness of the biofilm in the packing material was determined by selecting a pure membrane MBBR carrier from an actual engineering case. After washing with distilled water to remove suspended activated sludge from the carrier pores, the biofilm carrier was placed in water and observed under a microscope. Multiple fields of view were randomly selected to measure the thickness, take photos, and average the thickness from multiple measurements.

4. The evaluation method as described in claim 1, characterized in that, The ratio of the packing membrane to the suspended sludge is based on a pure membrane MBBR tank in an actual engineering case. 1L of the packing carrier and suspended sludge mixture is selected, and the packing carrier and suspended sludge are separated using a large-pore sieve. The MLSS1 and MLVSS1 of the suspended sludge liquid are measured using the ordinary activated sludge method. For biofilm carriers, after carefully washing away the suspended activated sludge in the pores of the carrier with distilled water, the biofilm on the surface of the carrier is completely peeled off. The carrier is then dried in a 105℃ forced-air drying oven to constant weight, cooled, and weighed. Next, it is ignited in a 600℃ muffle furnace to constant weight, cooled, and weighed. The MLSS2 and MLVSS2 are calculated. The ratio of MLSS2 of the carrier biofilm to MLSS1 of the suspended sludge is the MLSS ratio of the biofilm on the packing material and the suspended sludge. The ratio of MLVSS2 of the carrier biofilm to MLVSS1 of the suspended sludge is the MLVSS ratio of the biofilm on the packing material and the suspended sludge.

5. The evaluation method as described in claim 1, characterized in that, The abundance of microbial communities on the packing material was determined as follows: Pure membrane MBBR vector samples from actual engineering cases were taken, and microbial genomic DNA was extracted using a high-throughput sequencing kit. The integrity of the extracted genome was detected by 2% agarose gel electrophoresis, and EZNA was used to further analyze the DNA. The Soil DNA Kit was used to determine the concentration of genomic DNA. PCR amplification of the V3-V4 variable region of the 16S rRNA gene was performed using an upstream primer 338F (5'-ACTCCTACGGGAGGCAGCAG-3') carrying a barcode sequence and a downstream primer 806R (5'-GGACTACHVGGGTWTCTAAT-3'). The PCR products were recovered using a DNA gel recovery kit, and the recovered DNA was precisely quantified using a DNA detection kit. The DNA was then sequenced after being mixed in a 1:1 ratio. High-throughput sequencing of the samples was performed using the Illumina Miseq sequencing platform, and the abundance of denitrifying bacteria was calculated.

6. The evaluation method as described in claim 1, characterized in that, The biofilm formation rate was determined using a pilot-scale pure membrane MBBR system. Activated sludge from the aeration tank of a wastewater treatment plant was introduced into the pure membrane MBBR reactor as inoculum and aerated for 24 hours. Then, the supernatant was drained, and wastewater influent from the wastewater treatment plant was introduced for the experiment. Conventional aeration and stirring were performed in the pure membrane MBBR reactor for one month. The biofilm formation on the packing material was observed daily, photographed and recorded, and the amount of biofilm on the packing material was measured. The MLSS variation curve was plotted to fit the biofilm formation rate.

7. The evaluation method as described in claim 1, characterized in that, Shock resistance was determined using a pilot-scale device. After the pure membrane MBBR reactor was operating normally and stably, the influent flow rate was adjusted by a water pump and flow meter. At increases of 20%, 30%, 50%, 70%, and 100% in the influent flow rate, daily measurements of influent and effluent COD, TN, NH3-N, TP, and MLSS and SS levels within the reactor were taken. The treatment effect was compared and analyzed, and changes in biofilm thickness were observed and measured. Keeping the influent volume constant, the pilot plant used wastewater with different concentration gradients. When the COD, NH3-N, and TN levels were 1.2, 1.3, 1.5, 1.7, and 2.0 times that of the original water sample, respectively, the COD, TN, NH3-N, and TP levels of the influent and effluent, as well as the MLSS and SS levels in the reactor, were measured daily. The treatment effect was compared and analyzed, and the changes in biofilm thickness were observed and measured.

8. The evaluation method as described in claim 1, characterized in that, The determination of the biological nitrogen and phosphorus removal efficiency involves collecting the TP and TN influent and effluent of the pilot-scale device and the pure membrane MBBR unit in actual engineering cases, and calculating the TN and TP removal rates of the biochemical unit. Samples were taken and measured for TP and TN in the influent and effluent of the pure membrane MBBR over a 24-hour period on the same day; the nitrogen and phosphorus removal capacity was calculated.

9. The evaluation method as described in claim 1, characterized in that, The assessment method for the blockage of the packing mesh is to observe the water level difference on both sides of the packing mesh in actual engineering cases; The evaluation method for the aeration system is to collect dissolved oxygen values ​​of the influent, intermediate and terminal water of the aerobic section of a pure membrane MBBR tank in actual engineering cases. The evaluation of the anoxic tank mixing system involves collecting data on the number and power of mechanical agitators in actual engineering cases of anoxic tanks, and calculating the mixing density of the anoxic tank.

10. The evaluation method as described in claim 1, characterized in that, The pilot plant comprises, in sequence, a raw water tank, a pre-anoxic tank, an anoxic / aerobic adjustable tank, a pre-aerobic tank, a deoxygenated tank, a post-anoxic tank, a post-aerobic tank, a sedimentation tank, and an equipment room. Each tank is separated by steel plates and has overflow channels. These channels are designed with staggered flow patterns (top inlet, bottom outlet), and each overflow opening is equipped with a packing mesh. The pre-anoxic tank, the anoxic / aerobic adjustable tank, the pre-aerobic tank, the deoxygenated tank, the post-anoxic tank, and the post-aerobic tank are all equipped with pure water. The membrane MBBR packing material is used; mixers are installed in the raw water tank, the pre-anoxic tank, the anoxic / aerobic adjustable tank, the deoxygenation tank, and the post-anoxic tank; aeration systems are installed in the anoxic / aerobic adjustable tank, the pre-aerobic tank, and the post-aerobic tank; inclined tubes are installed in the sedimentation tank to enhance the sedimentation effect; the equipment room is equipped with a chemical dosing system, pumps, blowers, and control system, and the chemical dosing system is used to add chemicals to each tank through connecting pipelines; the pumps and blowers are connected to each tank through pipelines.

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