Denitrification functional strain mud domestication device and method rich in internal carbon source under low-carbon-source inlet water and application of denitrification functional strain mud domestication device

Abstract

The invention belongs to the technical field of environmental governance, and particularly relates to a domestication device and method for denitrifying functional strain mud rich in internal carbon sources under low-carbon-source inlet water and application of the domestication device and method. The device comprises a main flow anaerobic tank, a main flow aerobic tank and a secondary sedimentation tank which are sequentially connected in the sewage flowing direction, the aerobic tank is connected with a side flow anaerobic reactor, the side flow anaerobic reactor is connected with the water inlet end and the water outlet end of the aerobic tank, a water outlet is formed in the side wall of the secondary sedimentation tank, and the main flow anaerobic tank is connected with the main flow aerobic tank. And the bottom of the secondary sedimentation tank is connected with the bottom of the anaerobic tank. The device is simple in process layout, small in transformation land area and energy-saving, and when the device is used for microorganism enrichment and synchronous sludge reduction under low-carbon-source inlet water, the competition of aerobic heterotrophic microorganisms on dissolved oxygen and a carbon source can be avoided by fully utilizing the reducing power required by sludge return of the side-flow anaerobic reactor, so that DPAO or DGAO is enriched, and the aim of reducing the carbon source is fulfilled. Finally, enrichment of low-carbon-source microorganisms and reduction of sludge are achieved, and the synchronous denitrification effect is better.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental governance, and specifically relates to a device, method and application for acclimating denitrifying functional bacteria sludge rich in internal carbon source under low-carbon source water inflow. Background Art

[0002] Urban domestic sewage has different water quality characteristics in different cities at different times. The increasing urbanization level and people's living standards have led to an increase in daily water consumption. In addition, the construction of urban pipe networks has lagged behind and cannot keep up with the construction speed of sewage treatment plants. As a result, the lack of carbon sources has become a problem for sewage treatment plants to treat sewage, resulting in insufficient removal of nitrogen and phosphorus. At present, the cost of treating and disposing of residual sludge is high, accounting for about 20%-45% of the operating costs of sewage treatment plants. Therefore, it is necessary to develop a lower-cost sludge treatment process.

[0003] In-situ sludge reduction is a wastewater treatment technology that takes appropriate physical, chemical, biological and other measures on the basis of ensuring the quality of effluent, so that more energy is used to maintain the metabolism of sludge rather than for its proliferation. This in-situ sludge reduction technology is consistent with the goal of carbon reduction and neutralization. Among them, denitrifying phosphorus removal bacteria (DPAOs) and denitrifying polysaccharide removal bacteria (DGAOs) are important bacteria that enhance the denitrification and phosphorus removal effect under low-carbon source influent. Their growth requires less organic matter and dissolved oxygen (DO), saving >50% of aeration and reducing sludge production. They have a higher ability to resist shock loads, and their enrichment helps to reduce the carbon footprint of wastewater treatment processes that follow the concept of energy conservation and emission reduction. In the anaerobic stage, DPAOs can absorb VFAs by active transport and eventually store them in the cell in the form of PHA. This process is driven by intracellular polyphosphate hydrolysis and glycogenolysis; after entering the anoxic stage, DPAOs can be converted into NO 3- -N / NO 2- -N is used as an electron acceptor to decompose the intracellular carbon source PHA. Part of the energy generated is used for microbial growth and glycogen synthesis, and the rest of the energy is used to absorb excessive phosphate ions in the environment and store them in the form of polyphosphates in the cell body. After the anoxic stage, part of the phosphorus-rich sludge is discharged, and phosphorus is finally removed. Similar to DPAOs, DGAOs can convert VFA into endogenous storage substances under anaerobic conditions and store them in the cell as NO under anoxic conditions. 3- -N / NO 2- -N acts as an electron acceptor to consume intracellular storage substances, resulting in denitrification of internal carbon sources.

[0004] The simultaneous nitrification and denitrification phosphorus removal (SNDPR) process is a "multi-purpose carbon" process. Its sludge is rich in DPAOs and DGAOs. It is mainly operated in a batch mode in an anaerobic / aerobic sequence, but there are problems such as difficult to control treatment parameters, such as dissolved oxygen concentration. Since higher DO concentrations promote aerobic heterotrophic reactions and stimulate complete nitrification rather than promoting the growth of DPAOs and DGAOs, excessive dissolved oxygen concentrations will lead to incomplete denitrification and high N concentrations in the effluent. However, too low dissolved oxygen concentrations will lead to incomplete nitrification and affect the denitrification effect. Although the lower electron transfer rate of endogenous carbon source denitrifying bacteria is conducive to the reduction of their growth, the contribution of DPAOs and DGAOs enrichment to in-situ sludge reduction has not been deeply explored and studied. Therefore, it is urgent to develop a device and method for acclimating denitrifying functional bacteria rich in internal carbon sources under low-carbon source influent and its application in sludge reduction, so as to increase the abundance of denitrifying functional bacteria rich in internal carbon sources in sludge, thereby coping with the challenges of limited nitrogen and phosphorus removal capacity and insufficient sludge reduction potential under low-carbon source influent. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the present invention proposes a denitrifying functional bacteria sludge acclimation device rich in internal carbon source under low-carbon source influent, which is used in urban domestic sewage sludge reduction. By making full use of the reducing power required for the return sludge of the side-stream anaerobic reactor, the competition of aerobic heterotrophic microorganisms for dissolved oxygen and carbon source can be avoided, thereby enriching DPAO or DGAO, and finally achieving the enrichment of low-carbon source microorganisms and sludge reduction, and the synchronous denitrification effect is better.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention provides a denitrification functional bacteria sludge acclimation device rich in internal carbon source under low carbon source inlet water, the device comprises a mainstream anaerobic tank, a mainstream aerobic tank and a secondary sedimentation tank connected in sequence along the sewage flow direction, the aerobic tank is connected to a side stream anaerobic reactor, the side stream anaerobic reactor is connected to the water inlet and water outlet of the aerobic tank, the side wall of the secondary sedimentation tank is provided with a water outlet, and the bottom of the secondary sedimentation tank is connected to the bottom of the anaerobic tank. The mud inlet of the side stream anaerobic reactor is connected to the aerobic tank, which is convenient for processing the sludge in the aerobic tank, and the mud outlet of the side stream anaerobic reactor is connected to the aerobic tank, which is convenient for removing the sludge from the aerobic tank.

[0008] Preferably, the device further comprises a mainstream anoxic tank, wherein the anoxic tank is arranged between the anaerobic tank and the aerobic tank, and the anoxic tank is also connected to the water outlet of the aerobic tank.

[0009] Preferably, the side stream anaerobic reactor is a pulse aeration anaerobic reactor, and the side stream anaerobic reactor includes a stirring mechanism and an aeration device, wherein the stirring mechanism is arranged on the inner top wall of the side stream anaerobic reactor, and the aeration device is arranged on the inner bottom wall of the side stream anaerobic reactor. The stirring mechanism is used to stir the lower layer of muddy water mixed liquid and the supernatant liquid in the side stream anaerobic reactor to form a muddy water mixed liquid for mud discharge, or to stir the lower layer of muddy water mixed liquid and the supernatant liquid for mixing.

[0010] Preferably, the side-stream anaerobic reactor is supplied with mud and discharged with mud via a first driving pump and a second driving pump.

[0011] The second aspect of the present invention also provides the use of the denitrification functional bacteria sludge acclimation device rich in internal carbon source under low carbon source influent as described in the first aspect in reducing the amount of urban domestic sewage sludge.

[0012] The third aspect of the present invention further provides a method for synchronous sludge reduction by microbial enrichment under low-carbon source influent, wherein the low-carbon source sewage is treated by the denitrification functional bacteria sludge acclimation device rich in internal carbon source under low-carbon source influent described in the first aspect: the sewage enters the anaerobic tank, and is further treated by the aerobic tank or the anoxic tank and the aerobic tank, the mud-water mixture at the end of the aerobic tank enters the secondary sedimentation tank, or a part of it is returned to the anoxic tank and a part of it enters the secondary sedimentation tank in a ratio of 3:1, and the effluent is discharged after the mud-water separation in the secondary sedimentation tank; in this stage, only 95% of the mud-water mixture enters the secondary sedimentation tank or returns to the anoxic tank, and the remaining 5% of the mud-water mixture is returned to the side stream anaerobic reactor, and the sludge after the anaerobic treatment of the side stream anaerobic reactor flows into the aerobic tank again for further aerobic treatment, and the bottom flow from the secondary sedimentation tank can be fed back to the input end of the anaerobic tank, and the bottom flow can also be the output of the secondary sedimentation tank;

[0013] The specific operations of the above process include the following steps:

[0014] S1: Pre-processing:

[0015] Select appropriate influent water quality to ensure its low carbon source characteristics, where the influent COD is 150-180mg / L, NH4+-N: 10-40mg / L, TP: 1-4mg / L; the organic matter content in the water source is low, which can reduce the carbon source input in the subsequent treatment process. In the selection process, it is also possible to regularly monitor water quality indicators such as chemical oxygen demand COD, influent nitrogen source NH4+ and TN, influent phosphorus source TP, suspended solids SS, nutrients and heavy metals. These indicators can help determine whether the water quality is suitable, help to screen out water sources suitable for subsequent treatment, and carry out necessary physical and chemical pretreatment to remove larger particulate matter, so as to improve water quality and prevent the impact on subsequent treatment;

[0016] S2: Mainstream adjustment of anaerobic / aerobic ratio and selection of appropriate microbial populations:

[0017] In a low-carbon source environment, the anaerobic tank and aerobic tank of the mainstream biological selector combine wastewater and recycled biomass to promote internal carbon source conversion and high electron acceptor gradient formation, creating substrate conditions for internal carbon source denitrification functional bacteria. The hydraulic retention time ratio of the anaerobic tank and the aerobic tank is ≥1, and internal carbon source microorganisms with strong adaptability are screened to promote material circulation and energy flow, maintain ecological balance, and can also effectively degrade environmental pollutants and treat waste, which is conducive to the separation and enrichment of sludge;

[0018] S3: Optimize mainstream operation adjustments:

[0019] By adjusting the temperature, pH value, and DO, microorganisms can be cultured at different temperatures, different pH values, and different residence times, and the most suitable temperature, pH value, and residence time for microbial growth and reproduction can be selected, thereby promoting the growth and reproduction of microorganisms storing internal carbon sources and adjusting the distribution of carbon sources. Since the content of dissolved oxygen (DO) in water is affected by factors such as oxygen, temperature, and humidity in the air, a rapid dissolved oxygen (DO) detection tool is usually used for monitoring. The monitored number can be used to adjust the dissolved oxygen (DO) level, adjust the rear-end dissolved oxygen environment according to the effluent water quality, and remove COD, N, and P at the rear end of the aerobic pool;

[0020] S4: Implement synchronous extraction: During the treatment process, regularly extract the activated sludge enriched in the secondary sedimentation tank for resource reuse or treatment and disposal, so that the enriched sludge can be quickly separated and discharged from the system, thereby reducing the retention time of the sludge;

[0021] S5: Adjust the circulation flow system of the side-stream anaerobic reactor: adjust the sludge retention time of the side-stream anaerobic reactor to 10-15 days, and its hydraulic retention time to 3-10 days, the daily sludge exchange rate to 10-15%, and the sludge circulation flow frequency of the side-stream anaerobic reactor to 4-6 times / day to ensure the abundance of DPAO and DGAO and the stability of the system. By adopting a circulation flow system, the return ratio of microorganisms can be effectively improved, thereby increasing the concentration of microorganisms inside the system, promoting the interaction between similar microorganisms, and improving the treatment effect. In addition, a sludge return pipeline containing a side-stream anaerobic reactor with a long sludge retention time (SRT>5 days) is added to the aerobic tank in the traditional mainstream process; the phosphate and ammonia nitrogen released by the high concentration of biomass anaerobically in the side-stream anaerobic reactor ensure the P and N sources of DPAO and DGAO, and the longer anoxic effect brought to the mainstream ensures a higher ecological niche for the internal carbon source denitrification functional bacteria. At the same time, the side-flow anaerobic reactor eliminates microorganisms that are not suitable for growth in the alternate environment. The hidden growth brought about by their death achieves a reduction effect of up to 50%, further consolidating the dominant position of DPAO and DGAO.

[0022] S6: Side stream anaerobic reactor monitoring and adjustment: Regularly monitor the operating status of the side stream anaerobic reactor and the mainstream bioselector, including the concentration of organic matter in the sewage, microbial activity, ORP, pH, DO changes, and effluent quality, and timely adjust the operating parameters of the side stream anaerobic reactor to ensure the abundance of DPAO and DGAO and the stability of the system; for example, increase the first preset exchange frequency and the second preset exchange frequency of the side stream anaerobic reactor, the aeration times and aeration duration of the side stream anaerobic reactor.

[0023] Preferably, in S2, the hydraulic retention time of the anaerobic tank is adjusted to 2.7 hours, and the hydraulic retention time of the aerobic tank is adjusted to 2.3 hours; or the hydraulic retention time of the anaerobic tank is adjusted to 2 hours, the hydraulic retention time of the anoxic tank is adjusted to 2 hours, and the hydraulic retention time of the aerobic tank is adjusted to 2 hours.

[0024] Preferably, in S3, pH=7.5, DO=2-3 mg / L, T=25°C.

[0025] Preferably, in S5, aeration is added once every 2-3 hours after the sludge enters the side stream anaerobic reactor, and the aeration duration is 2 minutes.

[0026] Preferably, in S6, adjusting the operating parameters of the side stream anaerobic reactor includes adjusting a first preset exchange frequency and a second preset exchange frequency of the side stream anaerobic reactor, and the first preset exchange frequency and the second preset exchange frequency of the side stream anaerobic reactor are both 4-6 times / d; the basis for adjusting the operating parameters of the side stream anaerobic reactor includes a sludge concentration of 2500-3500 mg / L, pH=7-7.5, a DO change of 2-3 mg / L, and an effluent water quality of Class A standard.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention discloses a denitrifying functional bacteria sludge acclimation device rich in internal carbon source under low-carbon source influent, the device comprises a mainstream anaerobic tank, a mainstream aerobic tank and a secondary sedimentation tank connected in sequence along the sewage flow direction, the aerobic tank is connected to a side stream anaerobic reactor, the side stream anaerobic reactor is connected to the water inlet and water outlet of the aerobic tank, the side wall of the secondary sedimentation tank is provided with a water outlet, and the bottom of the secondary sedimentation tank is connected to the bottom of the anaerobic tank. The device has a simple process layout, requires less land area for transformation, saves energy, and is used for microbial enrichment and synchronous sludge reduction under low-carbon source influent. By making full use of the reducing power required for the return sludge of the side stream anaerobic reactor, the competition of aerobic heterotrophic microorganisms for dissolved oxygen and carbon source can be avoided, thereby enriching DPAO or DGAO, and finally achieving the enrichment of low-carbon source microorganisms and sludge reduction, and the synchronous denitrification effect is better. In general, the present invention has the following advantages:

[0029] (1) The method for simultaneous microbial enrichment and sludge reduction under low-carbon source influent provided by the present invention is to introduce a side stream anaerobic reactor with a long sludge retention time (SRT>5 days) into the aerobic tank of the traditional activated sludge process through a sludge return line. The daily sludge exchange rate is 10%-15%. When the anaerobic sludge is extremely hungry, it returns to the aerobic tank and competes for oxygen twice as much to restore its activity. The oxygen is controlled at a low level (0.5 mg / L-1 mg / L) to enhance the competitiveness of DGAO and DPAO against nitrate nitrogen. At the same time, controlling the low aeration volume of the mainstream can maximize the formation of the acquired anoxic section.

[0030] (2) The method for simultaneous microbial enrichment and sludge reduction under low-carbon source influent provided by the present invention is that the phosphate released in the return sludge is conducive to the absorption of DPAO into polyphosphate in an anoxic environment. At the same time, the long residence time created by the side-stream anaerobic reactor allows DGAO and DPAO with internal carbon sources to survive and perform endogenous denitrification or phosphorus removal in the mainstream aerobic system, further expanding the competitive advantage. In addition, the death rate of the return sludge in the side-stream anaerobic reactor increases under aerobic conditions, further promoting the hidden growth of the mainstream system and improving the enrichment of specialized microorganisms and the sludge reduction effect.

[0031] (3) The method for simultaneous sludge reduction by microbial enrichment under low-carbon source influent provided by the present invention can enrich endogenous denitrification functional bacteria by adjusting the mainstream anaerobic / aerobic ratio, so as to achieve better simultaneous nitrogen removal and phosphorus removal effects, and at the same time, can fully utilize the reducing power required for the return sludge of the side-stream anaerobic reactor, avoid the competition of aerobic heterotrophic microorganisms for DO, and then enrich DPAO or DGAO. The process layout is simple, the transformation area is small, energy is saved, and the enrichment of low-carbon source microorganisms and sludge reduction can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The A / O activated sludge treatment system of Example 1;

[0033] Figure 1 Among them, 110-anaerobic tank, 120-aerobic tank, 160-side stream anaerobic reactor, 130-second sedimentation tank, 170-stirring mechanism, 165-aeration device, 105-sewage outlet, 125-mud-water mixture pipeline, 145-mud inlet pipeline, 150-first driving pump, 180-mud outlet pipeline, 175-second driving pump, 135-output pipeline, 140-third driving pump, 190-water outlet.

[0034] Figure 2 The carbon source consumption and internal carbon source storage of the anaerobic tank 110 in the control group (CK) of Example 1 and the experimental group (AS) containing a side-stream anaerobic reactor.

[0035] Figure 3The robustness simulation results of the control group (CK) of Example 1 and the experimental group (AS) containing a side-flow anaerobic reactor.

[0036] Figure 4 The dissolved oxygen changes in the aerobic tank 120 in the control group (CK) of Example 1 and the experimental group (AS) containing a side-stream anaerobic reactor.

[0037] Figure 5 Graph showing the abundance of microorganisms in the aerobic tank 120 of the control group (CK) and the experimental group (AS) containing a side-stream anaerobic reactor.

[0038] Figure 6 The A / O activated sludge treatment system of Example 2;

[0039] 210-anaerobic tank, 220-anoxic tank, 230-aerobic tank, 280-side stream anaerobic reactor, 250-second sedimentation tank, 205-sewage outlet, 240-mud-water mixture pipeline, 265-mud inlet pipeline, 270-first drive pump, 290-mud outlet pipeline, 285-second drive pump, 255-output pipeline, 260-third drive pump, 295-water outlet, 235-output pipeline, 245-fourth drive pump.

[0040] Figure 7 The carbon source consumption and internal carbon source storage of the anaerobic tank 210 in the control group (CK) and the experimental group (AS) containing the side-stream anaerobic reactor of Example 2, as well as the relative proportions of polyphosphate bacteria PAO and polysaccharide bacteria GAO.

[0041] Figure 8 The non-endogenous denitrifying functional bacteria (Phase OL ) and endogenous denitrifying bacteria (Phase AL )Sludge reduction effect of enriched mainstream aerobic tank seed sludge. DETAILED DESCRIPTION

[0042] The specific embodiments of the present invention are further described below. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are commercially available unless otherwise specified.

[0044] Example 1

[0045] Figure 1An example of an A / O activated sludge treatment system 100 is provided, namely, a denitrification functional bacteria sludge acclimation device rich in internal carbon source under low carbon source influent. The device comprises an anaerobic tank 110, an aerobic tank 120 and a secondary sedimentation tank 130 connected in sequence along the flow direction of sewage, the aerobic tank 120 is connected to a side stream anaerobic reactor (pulse aeration anaerobic reactor) 160, the side stream anaerobic reactor 160 comprises a stirring mechanism 170 (such as a stirring paddle) and an aeration device 165, the stirring mechanism 170 is arranged on the inner top wall of the side stream anaerobic reactor 160, and is used to stir the lower layer of muddy water mixed liquid and the supernatant liquid in the side stream anaerobic reactor 160 to form a muddy water mixed liquid for mud discharge, or to stir the lower layer of muddy water mixed liquid and the supernatant liquid to mix them, and the aeration device 165 is arranged on the inner bottom wall of the side stream anaerobic reactor 160.

[0046] The anaerobic tank 110 is provided with a sewage outlet 105. The anaerobic tank 110 is connected to the aerobic tank 120. The aerobic tank 120 is connected to the mud inlet pipe 145 through a mud-water mixture pipeline 125. The other end of the mud inlet pipe 145 is connected to the side stream anaerobic reactor 160. The mud inlet pipe 145 is also provided with a first driving pump 150. The side stream anaerobic reactor 160 is connected to the aerobic tank 120 through a mud outlet pipe 180 and a second driving pump 175. The aerobic tank 120 is also connected to the secondary sedimentation tank 130 through the mud-water mixture pipeline 125. The bottom of the secondary sedimentation tank 130 is connected to the bottom of the anaerobic tank 110 through an output pipeline 135. The output pipeline 135 is provided with a third driving pump 140. The side wall of the secondary sedimentation tank 130 is also provided with a water outlet 190.

[0047] Figure 1 The working principle of the device shown is as follows: sewage enters the anaerobic tank 110 from the sewage outlet 105, and is further treated through the aerobic tank 120. The mud-water mixture at the end of the aerobic tank enters the secondary sedimentation tank 130 through the pipeline 125. The effluent obtained after the mud-water separation in the secondary sedimentation tank 130 is discharged through the outlet 190. In this stage, only 95% of the mud-water mixture enters the secondary sedimentation tank 130 through the pipeline 125, and the remaining 5% of the mud-water mixture flows back to the side stream anaerobic reactor 160 along the mud inlet pipeline 145 through the pipeline 125. The sludge after anaerobically treated in the side stream anaerobic reactor 160 flows into the aerobic tank 120 through the mud outlet pipeline 180 to continue aerobic treatment. The bottom flow from the secondary sedimentation tank 130 can be fed back to the input end of the anaerobic tank 110 through the output pipeline 135. The underflow may also be the output of the secondary settling tank 130 for further solids processing, such as thickening, stabilization, conditioning, dewatering, sludge handling, etc., as known to those of ordinary skill in the art.

[0048] Will Figure 1 The specific implementation steps of the device shown in the figure for sludge reduction are as follows:

[0049] S1: Pre-processing:

[0050] In order to reflect the acclimation and strengthening effect of the side stream anaerobic reactor 160, a device ( Figure 1 ) as the experimental group (AS), and the mainstream anaerobic tank 110, aerobic tank 120 and secondary sedimentation tank 130 without the side stream anaerobic reactor 160 and the corresponding supporting pipelines are set as the control group (CK). Both groups are equipped with the same sewage to simulate the influent water quality of urban domestic sewage to ensure its low carbon source characteristics (COD < 200 mg / L), where the influent COD is 150-180 mg / L, NH4 + -N: 30-40mg / L, TP: 2-4mg / L.

[0051] S2: Adjust the mainstream anaerobic / aerobic ratio and select the appropriate microbial population:

[0052] The hydraulic retention time of the anaerobic tank 120 is adjusted to 2.7 hours, and the hydraulic retention time of the aerobic tank 120 is adjusted to 2.3 hours, wherein the extended retention time of the anaerobic tank is used to screen internal carbon source storage microorganisms with strong adaptability, so as to promote material circulation and energy flow, maintain ecological balance, and enable them to effectively degrade environmental pollutants and promote them to fully treat waste, thereby facilitating the separation and enrichment of sludge;

[0053] S3: Optimize mainstream operation adjustments:

[0054] By adjusting the temperature of the anaerobic tank 110 or the aerobic tank 120, the pH value of the anaerobic tank 110 or the aerobic tank 120, the DO of the aerobic tank 120 and other operating conditions, the microorganisms are cultured at different temperatures, different pH values ​​and different residence times to select the temperature most suitable for the growth and reproduction of the microorganisms. The final screening results are: pH = 7.5, DO = 2-3 mg / L, T = 25°C;

[0055] S4: Implement synchronous extraction: During the treatment process, the activated sludge enriched in the secondary sedimentation tank 130 is regularly extracted for resource reuse or treatment and disposal, so that the enriched sludge is quickly separated and discharged from the system, thereby reducing the retention time of the sludge;

[0056] S5: Regulate the sludge circulation flow system of the side-stream anaerobic reactor 160: Introduce a side-stream anaerobic reactor 160 with a long sludge retention time (SRT = 10d) into the aerobic tank 120, the hydraulic retention time is 3d, the daily sludge exchange rate is 10%, and the sludge exchange frequency of the side-stream anaerobic reactor 160 is 4 times / day, that is, the first preset exchange frequency and the second preset exchange frequency of the side-stream anaerobic reactor 160 are both 4 times / d. To ensure the abundance of DPAO and DGAO and the stability of the system. By adopting the sludge circulation flow system of the side-stream anaerobic reactor 160, the dynamic balance of the sludge population can be effectively maintained. The long-term anaerobic starvation environment of the side-stream anaerobic reactor 160 can further screen out denitrifying phosphorus removal bacteria (DPAO) and denitrifying polysaccharide bacteria (DGAO) with internal carbon source storage function, and make them dominant strains. Moreover, the phosphate and ammonia nitrogen released by the high concentration of biomass in the side-flow anaerobic reactor 160 ensure the P and N sources of DPAO and DGAO, and ensure that the internal carbon source denitrification functional bacteria maintain a higher ecological niche through a longer hypoxic effect. In addition, the side-flow anaerobic reactor 160 eliminates microorganisms that are not suitable for growth in the alternate environment, accelerating the death of mainstream microorganisms and the hidden growth they bring.

[0057] S6: Monitoring and adjustment of the side stream anaerobic reactor 160: Regularly monitor the operating status of the side stream anaerobic reactor 160 and the mainstream bioselector, and timely adjust the operating parameters of the side stream anaerobic reactor 160 to ensure the stability of indicators including sludge concentration (2500-3500 mg / L), microbial activity, pH (7-7.5), DO change (2-3 mg / L), effluent water quality (Grade A standard) and so on.

[0058] S7: Research and deepening of enriched microorganisms: Determine and calculate the microbial carbon source consumption (difference in sewage COD before and after entering the mainstream anaerobic tank) and the microbial internal carbon source storage (difference between the COD value of microbial carbon source consumption and the COD value of external denitrification in the mainstream anaerobic tank) of the control group (CK) and the experimental group (AS) containing the side-stream anaerobic reactor 160, in order to verify the enrichment effect of DPAO and DGAO. At the same time, sludge was taken from the end of the aerobic tanks of CK and AS and stored at -80°C for full-length 16S rRNA sequencing analysis to monitor the changes in microbial abundance in the control group (CK) and the experimental group (AS) containing the side-stream anaerobic reactor, and to deepen the study of the specific types of enriched DPAO and DGAO. The 16S amplicon sequencing experimental process was performed according to the standard protocol provided by Illumina, including sample quality detection, library construction, library quality detection, and library sequencing.

[0059] Figure 2Figure 2 shows the carbon source consumption and internal carbon source storage in the anaerobic tank 110 in the control group (CK) and the experimental group (AS) containing the side-flow anaerobic reactor 160. The internal carbon source conversion of the carbon source in AS (87%) was higher than that in CK (75%), indicating that after adding the side-flow anaerobic reactor 160, more of the carbon source consumed in the anaerobic tank was stored by microorganisms as an internal carbon source, which indirectly reflects the increased enrichment of internal carbon source bacteria.

[0060] Figure 3 The robustness simulation results of the control group (CK) and the experimental group (AS) containing a side-flow anaerobic reactor indicate that AS has higher stability and the ability to resist shock loads. Robustness represents the stability of the microbial network. The simulation method is to use the ASV table obtained by 16S sequencing to calculate the proportion of remaining nodes in the microbial network after a certain proportion of nodes are randomly removed. The higher the proportion of remaining nodes, the more stable the microbial community.

[0061] Figure 4 The dissolution changes in the aerobic tank 120 in the control group (CK) and the experimental group (AS) containing the side-flow anaerobic reactor. After aeration began, the return sludge from the side-flow anaerobic reactor 160 returned to the aerobic tank 120. Unlike the gradual increase in dissolved oxygen in CK, the dissolved oxygen in AS was lower than 1 mg / L within one hour, which was an anoxic state, which was conducive to the enrichment of denitrifying bacteria.

[0062] Figure 5 The top ten species in terms of microorganism abundance in the aerobic tank 120 of the control group (CK) and the experimental group (AS) containing the side-stream anaerobic reactor are shown in Figure 1, indicating that after the addition of the side-stream anaerobic reactor 160, the return sludge of the side-stream anaerobic reactor 160 can be used to bring about the low dissolved oxygen effect required by DPAO and DGAO, and the long-term anaerobic and aerobic alternating environment of the side-stream anaerobic reactor 160 can further screen out DPAO and DGAO with internal carbon sources, making them form dominant species, thereby achieving an increase in the abundance of DGAO and DPAO.

[0063] Example 2

[0064] On the basis of the device in Example 1, an anoxic tank is added to construct a denitrification functional bacteria sludge acclimation device rich in internal carbon source under low carbon source influent, such as Figure 6The A / O activated sludge treatment system 200 is shown in FIG. The device comprises an anaerobic tank 210, an anoxic tank 220, an aerobic tank 230 and a secondary sedimentation tank 250 which are sequentially connected along the flow direction of sewage. The aerobic tank 230 is connected to a side stream anaerobic reactor (pulse aeration anaerobic reactor) 280. The side stream anaerobic reactor 280 is also provided with a stirring mechanism (such as a stirring paddle) and an aeration device. The stirring mechanism is provided on the inner top wall of the side stream anaerobic reactor 280, and is used to stir the lower layer of muddy water mixed liquid and the supernatant liquid in the side stream anaerobic reactor 280 to form a muddy water mixed liquid for mud discharge, or to stir the lower layer of muddy water mixed liquid and the supernatant liquid to mix them evenly. The aeration device is provided on the inner bottom wall of the side stream anaerobic reactor 280.

[0065] The anaerobic tank 210 is provided with a sewage outlet 205. The anaerobic tank 210 is connected to the anoxic tank 220, and the anoxic tank 220 is connected to the aerobic tank 230. The aerobic tank 230 is connected to the mud inlet pipeline 265 through the mud-water mixture pipeline 240. The other end of the mud inlet pipeline 265 is connected to the side stream anaerobic reactor 280. The mud inlet pipeline 265 is also provided with a first driving pump 270, and the side stream anaerobic reactor 280 is connected to the aerobic tank 230 through a mud outlet pipeline 290 and a second driving pump 285; the aerobic tank 230 is also connected to the secondary sedimentation tank 250 through the mud-water mixture pipeline 240, and the bottom of the secondary sedimentation tank 250 is connected to the bottom of the anaerobic tank 210 through an output pipeline 255, and the output pipeline 255 is provided with a third driving pump 260. The side wall of the secondary sedimentation tank 250 is also provided with a water outlet 295. The aerobic pool 230 is also connected to an output pipeline 235 via a mud-water mixture pipeline 240 . A fourth driving pump 245 is disposed on the output pipeline 235 . The other end of the output pipeline 235 is connected to the anoxic pool 220 .

[0066] Figure 6The working principle of the device shown is as follows: sewage enters the anaerobic tank 210 from the sewage outlet 205, and is further treated through the anoxic tank 220 and the aerobic tank 230. The mud-water mixture at the end of the aerobic tank is respectively returned to the anoxic tank 220 and enters the secondary sedimentation tank 250 through the pipeline 240 in a ratio of 3:1. The effluent obtained after the mud-water separation in the secondary sedimentation tank 250 is discharged through the outlet 295. In this stage, only 95% of the mud-water mixture enters the secondary sedimentation tank 250 or returns to the anoxic tank 220 through the pipeline 240, and the remaining 5% of the mud-water mixture is returned to the side stream anaerobic reactor 280 along the mud inlet pipeline 265 through the pipeline 240. The sludge after anaerobically treated in the side stream anaerobic reactor 280 flows into the aerobic tank 230 through the mud outlet pipeline 290 to continue aerobic treatment. The bottom flow from the secondary sedimentation tank 250 can be fed back to the input end of the anaerobic tank 210 through the output pipeline 255. The underflow may also be the output of the secondary settling tank 250 for further solids processing, such as thickening, stabilization, conditioning, dewatering, sludge handling, etc., as known to those of ordinary skill in the art.

[0067] Will Figure 6 The specific implementation steps of the device shown in the figure for sludge reduction are as follows:

[0068] S1: Pre-processing:

[0069] In order to reflect the acclimation and strengthening effect of the side stream anaerobic reactor 280, a device including a mainstream anaerobic tank 210, an aerobic tank 230 and a secondary sedimentation tank 250 and corresponding supporting pipelines is provided. Figure 6 ) as the experimental group (AS), and the mainstream anaerobic tank 210, aerobic tank 230 and secondary sedimentation tank 250 without the side stream anaerobic reactor 280 and the corresponding supporting pipelines were set as the control group (CK). Both groups were equipped with the same sewage to simulate the influent water quality of urban domestic sewage to ensure its low carbon source characteristics, in which the influent COD was 170 mg / L, NH4 + -N: 10-25mg / L, TP: 1-2mg / L.

[0070] S2: Adjust the mainstream anaerobic / aerobic ratio and select the appropriate microbial population:

[0071] The hydraulic retention time of the anaerobic tank 210, the hydraulic retention time of the anoxic tank 220 and the hydraulic retention time of the aerobic tank 230 are adjusted to 2 hours, wherein the extended retention time of the anaerobic tank is used to screen internal carbon source storage microorganisms with strong adaptability, so as to promote material circulation and energy flow, maintain ecological balance, and effectively degrade environmental pollutants, promote them to fully treat waste, thereby facilitating the separation and enrichment of sludge;

[0072] S3: Optimize mainstream operation adjustments:

[0073] By adjusting the operating conditions such as temperature, pH value, DO, etc., the microorganisms are cultured at different temperatures, different pH values ​​and different residence times to select the temperature most suitable for the growth and reproduction of microorganisms. The final screening results are: pH = 7.5, DO = 2-3 mg / L, T = 25°C;

[0074] S4: Implement synchronous extraction: During the treatment process, regularly extract the activated sludge enriched in the secondary sedimentation tank 250 for resource reuse or treatment and disposal, so that the enriched sludge can be quickly separated and discharged from the system, thereby reducing the retention time of the sludge;

[0075] S5: Adjust the sludge circulation flow system of the side-stream anaerobic reactor 280: Introduce a side-stream anaerobic reactor 280 with a long sludge retention time (12d) into the aerobic tank 230, the hydraulic retention time is 5d, and the daily sludge exchange rate is 15%. The long-term anaerobic starvation environment of the side-stream anaerobic reactor 280 can further screen out denitrifying phosphorus removal bacteria (DPAO) and denitrifying polysaccharide bacteria (DGAO) with internal carbon source storage function, and make them dominant bacteria. The sludge exchange frequency of the side-stream anaerobic reactor 280 is 6 times / d, that is, the first preset exchange frequency and the second preset exchange frequency of the side-stream anaerobic reactor 160 are both 6 times / d. After the sludge enters the side-stream anaerobic reactor 280, aeration is increased once every 3 hours, and each aeration lasts for 2min. The decay rate of DGAO under intermittent aeration conditions is greater than that of DPAO, thereby increasing the proportion of enriched PAO.

[0076] S6: Monitoring and adjustment of the side stream anaerobic reactor 280: Regularly monitor the operating status of the side stream anaerobic reactor 280 and the mainstream bioselector, and timely adjust the operating parameters of the side stream anaerobic reactor 280 to ensure the stability of indicators including sludge concentration (2500-3500 mg / L), microbial activity, pH (7-7.5), DO change (2-3 mg / L), effluent water quality (Grade A standard), etc.

[0077] S7: Research and optimization: With the deepening of practice, keeping other conditions unchanged, the retention time of anaerobic tank 210 was shortened from 2h to 1.7h, and the retention time of aerobic tank 23 was extended from 2h to 2.3h, and the performance of seed sludge enriched with non-endogenous denitrifying functional bacteria (PhaseOL) and endogenous denitrifying functional bacteria (PhaseAL) in sludge reduction was compared.

[0078] Figure 7The carbon source consumption and internal carbon source storage of the anaerobic tank 210 in the control group (CK) and the experimental group (AS) containing the side-flow anaerobic reactor of this embodiment, as well as the relative proportions of polyphosphate bacteria PAO and polysaccharide bacteria GAO. It can be seen that the internal carbon source ratio (91%) in AS (outer circle) is higher than that in CK (inner circle) (80%), indicating that after the side-flow anaerobic reactor 280 is added, the carbon source consumed in the anaerobic tank 210 is more stored by microorganisms as an internal carbon source, which indirectly reflects the increase in the enrichment of internal carbon source bacteria. The PAO ratio of AS (outer circle) is 11% higher than that of CK (inner circle), indicating that the intermittently aerated side-flow anaerobic reactor 280 increases the proportion of DPAO.

[0079] Figure 8 The results of the sludge reduction effect of the mainstream aerobic pool seed sludge enriched with non-endogenous denitrifying functional bacteria (PhaseOL) and endogenous denitrifying functional bacteria (PhaseAL) showed that the sludge reduction effect was 51.92% after shortening the residence time of the anaerobic pool 210 to 1.7h and extending the residence time of the aerobic pool 230 to 2.3h, so that the endogenous denitrifying functional bacteria were enriched (PhaseAL). However, after enriching the non-endogenous denitrifying functional bacteria (PhaseOL), the sludge reduction effect was only 36.79%. Moreover, the death of the return sludge microorganisms in the side stream anaerobic reactor 280 increased under aerobic conditions, which further improved the sludge reduction effect.

[0080] In summary, the denitrifying functional bacteria sludge acclimation device rich in internal carbon source under low carbon source influent provided by the present invention can utilize the mainstream in-situ low dissolved oxygen zone brought by the return sludge of the side-stream anaerobic reactor, and the long-term anaerobic starvation environment of the side-stream anaerobic reactor, and can further screen out denitrifying phosphorus removal bacteria (DPAO) and denitrifying polysaccharide bacteria (DGAO) with internal carbon source storage function, and make them the mainstream dominant bacteria, and the lower energy transfer efficiency of the side-stream anaerobic reactor makes the sludge growth rate slower, so as to achieve the rapid establishment of synchronous nitrification, denitrification and phosphorus removal and the stable operation of sludge reduction. At the same time, the phosphate and ammonia nitrogen released by the high concentration of biomass anaerobically in the side-stream anaerobic reactor ensure the P and N sources of DPAO and DGAO, and the longer hypoxia effect brought to the mainstream anaerobic and aerobic pools can ensure the higher ecological niche of the internal carbon source denitrifying functional bacteria. The side-stream anaerobic reactor eliminates microorganisms that are not suitable for growth in the alternating environment, and its accelerated mainstream microbial death and the hidden growth brought by it achieve an in-situ sludge reduction effect of up to 50%. In addition, the frequency and range of the change in redox potential can be increased by changing the sludge return frequency or adding stirring, aeration and other equipment in the side-stream anaerobic reactor, thereby effectively realizing the differentiation of N and P microorganisms in the process to meet the requirements of denitrification and phosphorus removal under different water inlet conditions. Therefore, the device provided by the present invention and the method for simultaneous sludge reduction by microbial enrichment under low-carbon source water inlet have simple process layout, small land area for transformation, and energy saving. By making full use of the reducing power required for the return sludge of the side-stream anaerobic reactor, the competition of aerobic heterotrophic microorganisms for dissolved oxygen and carbon sources can be avoided, thereby enriching DPAO or DGAO, and finally achieving the enrichment of low-carbon source microorganisms and sludge reduction, and the simultaneous denitrification effect is better.

[0081] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the protection scope of the present invention.

Claims

1. A denitrification functional bacteria sludge acclimation device rich in internal carbon source under low carbon source inlet water, characterized in that: The device comprises a mainstream anaerobic tank, a mainstream aerobic tank and a secondary sedimentation tank which are sequentially connected along the flow direction of sewage; the aerobic tank is connected to a side stream anaerobic reactor, the side stream anaerobic reactor is connected to the water inlet and the water outlet of the aerobic tank; a water outlet is arranged on the side wall of the secondary sedimentation tank, and the bottom of the secondary sedimentation tank is connected to the bottom of the anaerobic tank.

2. The denitrification functional bacteria sludge acclimation device rich in internal carbon source under low carbon source inflow according to claim 1, characterized in that: The device also includes a mainstream anoxic tank, which is arranged between the anaerobic tank and the aerobic tank, and is also connected to the water outlet of the aerobic tank.

3. The denitrification functional bacteria sludge acclimation device rich in internal carbon source under low carbon source inflow according to claim 1 or 2, characterized in that: The side stream anaerobic reactor is a pulse aeration anaerobic reactor, which comprises a stirring mechanism and an aeration device. The stirring mechanism is arranged on the inner top wall of the side stream anaerobic reactor, and the aeration device is arranged on the inner bottom wall of the side stream anaerobic reactor.

4. The denitrification functional bacteria sludge acclimation device rich in internal carbon source under low carbon source inflow according to claim 1 or 2, characterized in that: The side-flow anaerobic reactor is supplied with mud and discharged with mud via a first driving pump and a second driving pump.

5. Application of the denitrification functional bacteria sludge acclimation device rich in internal carbon source under low carbon source influent as described in any one of claims 1 to 4 in reducing the amount of urban domestic sewage sludge.

6. A method for simultaneous sludge reduction by microbial enrichment under low carbon source influent, characterized in that: The low-carbon source sewage is treated by using the denitrification functional bacteria mud acclimation device rich in internal carbon source under low-carbon source inlet water as described in any one of claims 1 to 4: the sewage enters the anaerobic tank and is further treated through the aerobic tank or the anoxic tank and the aerobic tank, the mud-water mixture at the end of the aerobic tank enters the secondary sedimentation tank, or a part of it is returned to the anoxic tank in a ratio of 3:1, and a part of it enters the secondary sedimentation tank, and the effluent is discharged after the mud and water are separated in the secondary sedimentation tank; in this stage, only 95% of the mud-water mixture enters the secondary sedimentation tank or returns to the anoxic tank, and the remaining 5% of the mud-water mixture is returned to the side stream anaerobic reactor, and the sludge after anaerobically treated in the side stream anaerobic reactor flows into the aerobic tank to continue aerobic treatment, and the bottom flow from the secondary sedimentation tank can be fed back to the input end of the anaerobic tank, and the bottom flow can also be the output of the secondary sedimentation tank; The specific operations of the above process include the following steps: S1: Pre-processing: Select appropriate influent water quality to ensure its low carbon source characteristics, where the influent COD is 150-180mg / L, NH4 + -N: 10-40mg / L, TP: 1-4mg / L; S2: Mainstream adjustment of anaerobic / aerobic ratio and selection of appropriate microbial populations: Make the hydraulic retention time ratio of anaerobic tank to aerobic tank ≥1, select internal carbon source microorganisms with strong adaptability to promote material circulation and energy flow, maintain ecological balance, and effectively degrade environmental pollutants and treat waste, which is conducive to the separation and enrichment of sludge; S3: Optimize mainstream operation adjustments: By adjusting the temperature, pH value, and DO, the microorganisms are cultured at different temperatures, different pH values, and different residence times, and the temperature, pH value, and residence time that are most suitable for the growth and reproduction of microorganisms are selected, thereby promoting the growth and reproduction of microorganisms that store internal carbon sources and adjusting the distribution of carbon sources; S4: Implement synchronous extraction: During the treatment process, regularly extract the activated sludge enriched in the secondary sedimentation tank for resource reuse or treatment and disposal, so that the enriched sludge can be quickly separated and discharged from the system, thereby reducing the retention time of the sludge; S5: Adjust the circulation system of the side stream anaerobic reactor: Adjust the sewage flow of the side stream anaerobic reactor Mud residence time The sludge circulation rate of the side stream anaerobic reactor is 4-6 times / day to ensure the abundance of DPAO and DGAO and the stability of the system. S6: Side stream anaerobic reactor monitoring and adjustment: Regularly monitor the operating status of the side stream anaerobic reactor and the mainstream bioselector, including the concentration of organic matter in the sewage, microbial activity, ORP, pH, DO changes, and effluent quality, and adjust the operating parameters of the side stream anaerobic reactor in time to ensure the abundance of DPAO and DGAO and the stability of the system.

7. The method for microbial enrichment and simultaneous sludge reduction under low-carbon source influent according to claim 6, characterized in that: In S2, the hydraulic retention time of the anaerobic tank is adjusted to 2.7 hours, and the hydraulic retention time of the aerobic tank is adjusted to 2.3 hours; or the hydraulic retention time of the anaerobic tank is adjusted to 2 hours, the hydraulic retention time of the anoxic tank is adjusted to 2 hours, and the hydraulic retention time of the aerobic tank is adjusted to 2 hours.

8. The method for simultaneous sludge reduction by microbial enrichment under low carbon source influent according to claim 6, characterized in that: In S3, pH = 7.5, DO = 2-3 mg / L, T = 25°C.

9. The method for simultaneous sludge reduction by microbial enrichment under low carbon source influent according to claim 6, characterized in that: In S5, aeration was increased every 2-3 hours after the sludge entered the side stream anaerobic reactor, and the aeration duration was 2 minutes.

10. The method for simultaneous sludge reduction by microbial enrichment under low carbon source influent according to claim 6, characterized in that: In S6, adjusting the operating parameters of the side flow anaerobic reactor includes adjusting a first preset exchange frequency and a second preset exchange frequency of the side flow anaerobic reactor, wherein the first preset exchange frequency and the second preset exchange frequency of the side flow anaerobic reactor are both 4-6 times / d; The basis for adjusting the operating parameters of the side stream anaerobic reactor includes sludge concentration of 2500-3500 mg / L, pH=7-7.5, DO change of 2-3 mg / L, and effluent water quality of Class A standard.

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