A low pollution water efficient bioaugmentation treatment and toxicity reduction system and method of operation

Abstract

The application provides a low-pollution water efficient biological reinforcement treatment and toxicity reduction system and an operating method, comprising a pre-warning control system, a tail water treatment system, a receiving water body and a backflow system, characterized in that the tail water treatment system comprises, which are connected in sequence, an adjusting pond, an ecological pond, a drum microfilter, an anoxic tank, an MBBR tank, a secondary sedimentation tank and a clear water tank; the drum microfilter and the secondary sedimentation tank are connected with a sludge digestion tank respectively, and the sludge digestion tank is also connected with the anoxic tank. The application realizes the modularization of the treatment facility, improves the purification efficiency of the low-pollution tail water, solves the problems of the total amount of the tail water pollutant emission and the total amount of the toxicity reduction safe emission of the sewage treatment plant, and has the advantages of convenient detection, high sensitivity, convenient operation, low investment, environmental friendliness and the like, and can be adjusted to adapt to low C / N. When the system C / N is insufficient, the sludge digestion tank backflow supernatant is supplemented through a side flow to make up the carbon source of the system, so that the low C / N sewage treatment is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water body treatment, in particular to a low-pollution efficient biological reinforcement treatment and toxicity reduction system and operation method. BACKGROUND

[0002] Developing advanced treatment and reuse of tail water from municipal wastewater treatment plants can not only reduce environmental pollution load, but also open up new water sources for towns.

[0003] The treatment device in the prior art generally uses a screen filtration interception method to filter floating and suspended solids in the tail water during primary treatment of low-pollution water. Since the content of floating and suspended solids in the tail water that has not been treated is high, the phenomenon of clogging the filter screen often occurs due to too much aggregated floating and suspended solids during the filtration process of the tail water in the primary treatment. The impurities on the filter screen need to be manually cleaned, which is time-consuming and labor-intensive and has poor cleaning effect, thereby reducing the working efficiency of the entire treatment device.

[0004] Polyurethane fillers have high porosity, large specific surface area, and fast biofilm formation speed, and are the preferred filler for MBBR and other processes. For example, Chinese Patent Application No. CN201910542399.9 discloses a new MBBR filler structure and its preparation technology method, which realizes rapid biofilm formation of polyurethane fillers, and the process effect of polyurethane fillers needs to be investigated in actual operation. Chinese Patent Application No. CN201910443516.6 discloses a denitrification and phosphorus removal process based on an AA-MBBR device, which improves the low-temperature treatment effect of the device by adding powdered activated carbon and improves the low carbon-nitrogen ratio treatment effect by inverting operation. However, the system is complex to construct and cannot completely solve the problems of low temperature and low carbon-nitrogen ratio. Chinese Patent Application No. CN202010555017.9 discloses an integrated sewage treatment equipment and method based on A / O-MBBR process, which realizes convenient operation and maintenance and cost reduction of A / O-MBBR process. However, the system still needs to improve its resistance to impact load, and the residual sludge has not been resourceized. To solve this problem, there is an urgent need for a high-efficiency, time-saving, and labor-saving tail water treatment device for sewage plants, which can adapt to low temperature, low carbon-nitrogen ratio, and other working conditions through technical compensation. SUMMARY

[0005] Invention purposes: In view of the prominent problems of large discharge amount and high toxicity of low pollution water body, the present application provides a low pollution efficient biological strengthening treatment and toxicity reduction system and operation method, and proposes a running method for treating low pollution water by using the above device. The present application realizes the modularization of the treatment facility, improves the purification efficiency of the low pollution tail water, solves the problems of total amount of pollutant discharge and total amount of toxicity reduction of tail water in sewage treatment plant, and has the advantages of convenient detection, high sensitivity, convenient operation, low investment, environmental friendliness and the like, and can adapt to low C / N by adjustment. When the C / N of the system is insufficient, the supernatant of the sludge digestion tank is supplemented by side flow reflux, the carbon source of the system is made up, and low C / N sewage treatment is realized.

[0006] In order to solve the above technical problems, the present application discloses a low pollution water efficient biological strengthening treatment and toxicity reduction system, which comprises a pre-warning control system (1), a tail water treatment system (2), a receiving water body (3) and a reflux system (4), characterized in that the tail water treatment system (2) comprises a regulating pond (2-1), an ecological pond (2-2), a drum microfilter (2-3), an anoxic tank (2-4), an MBBR tank (2-5), a secondary sedimentation tank (2-6) and a clear water tank (2-7) connected in sequence; the drum microfilter (2-3) and the secondary sedimentation tank (2-6) are connected with a sludge digestion tank (2-8) respectively, so as to facilitate the discharge of the treated sludge, and the sludge digestion tank (2-8) is also connected with the anoxic tank (2-4), so as to supplement the carbon source.

[0007] The ecological pond (2-2) is provided with an ecological floating island (2-2-21) and aquatic plants (2-2-2), the ecological floating island (2-2-1) comprises a bed body, a floating island carrier arranged on the bed body and floating island plants, the bed body is made of a PVC pipe, the floating island carrier is bound by a high-strength nylon fishing net, and the floating island plants are in the form of a combination of round coin grass and Myriophyllum propinquum.

[0008] The MBBR tank (2-5) is provided with a sludge discharge pipe (2-5-1), a flow guide cylinder (2-5-2) and an MBBR tank water inlet pipe (2-5-3), the flow guide cylinder (2-5-2) is used for guiding the flow of sewage entering the MBBR tank, improving the contact effect of the sewage and the porous gel suspended filler, and then efficiently treating the pollutants in the sewage; the MBBR tank (2-5) is internally provided with a porous gel suspended filler, the porous gel suspended filler is made of polyurethane material, has a specific surface area of 2500-3500 m 2 / m 3 , a porosity of ≥98%, and a reaction tank filling rate of 15-30%; the active sludge is used to complete the film formation time of the porous gel suspended filler for 7-10 days; and the service life is >10 years.

[0009] The early warning control system (1) comprises a flow and water quality early warning device (1-1) and a toxicity early warning device (1-2), the early warning devices are connected to early warning monitoring points through sensors, the flow and water quality early warning device (1-1) can detect flow and conventional water quality data at the same time, and the toxicity early warning device (1-2) is used for monitoring the content change of characteristic pollutants.

[0010] The application further provides an operation method of the low-pollution high-efficiency biological strengthening treatment and toxicity reduction system.

[0011] Step 1: The tail water of the sewage plant enters the ecological pond (2-2) from the adjusting pond (2-1) through a pipeline or the like, and the micro-ecological purifying agent is added into the ecological pond (2-2) at the same time;

[0012] Step 2: The wastewater in the ecological pond (2-2) is pumped into the rotary drum micro-filter (2-3) by a water pump to perform SS and COD filtration treatment, and the treated sludge is discharged into the sludge digestion tank (2-8) for further digestion treatment, and the digestion supernatant is returned to the anoxic tank (2-4) as a supplementary carbon source;

[0013] Step 3: After the wastewater is filtered by the rotary drum micro-filter (2-3), the wastewater enters the anoxic tank (2-4) and the MBBR tank (2-5) to perform aeration treatment, so as to remove total nitrogen, COD and ammonia nitrogen pollutants respectively, the flow and water quality early warning device (1-1) detects the water quality before and after purification, the internal reflux tail water amount is determined according to the treatment efficiency of the pollutants, and the calculation formula is as shown in formula 1:

[0014] (Formula 1)

[0015] Note that alpha is the tail water purification efficiency.

[0016] R : The external reflux ratio is generally controlled to be (30-50%).

[0017] r : The internal reflux ratio.

[0018] According to the calculation result, part of the tail water reenters the anoxic tank (2-4) through the reflux system (4) to perform secondary purification treatment.

[0019] Step 4: The tail water not entering the reflux system (4) passes through the MBBR tank (2-5) and enters the secondary sedimentation tank (2-6) in which coagulants are reserved, the sludge is discharged into the sludge digestion tank (2-8) after sedimentation, the flow and water quality early warning device (1-1) detects the water quality before and after purification, and part of the sludge is added into the anoxic tank (2-4) through the reflux system (4) to perform tertiary purification treatment according to the external reflux ratio R.

[0020] The fifth step: the last tail water enters the clean water pool (2-7) for disinfection treatment, and the flow and water quality early warning device (1-1) and the toxicity early warning device (1-2) check the tail water to determine whether the purification meets the standard, if it meets the standard, the tail water of the sewage plant can enter the receiving water body (3), otherwise it needs to enter the tail water treatment system (2) for reprocessing through the backflow system (4).

[0021] In step (5), the determination formula of whether it meets the standard is as follows (formula 2):

[0022] ; ; ; ; ; (formula 2)

[0023] Note: COD concentration in the standard tail water and the discharged tail water, mg;

[0024] Q 0, Q : flow index of the standard tail water and the discharged tail water, m 3 / s;

[0025] I 0, I : toxicity index of the standard tail water and the discharged tail water, mg / m 3 ;

[0026] W 0, W : total amount of pollutants discharged in the standard tail water and the discharged tail water, mg;

[0027] T 0, T : total amount of toxic substances discharged in the standard tail water and the discharged tail water, mg.

[0028] Wherein, the tail water of the sewage treatment plant is detected by the flow and water quality early warning device (1-1), the flow index Q is less than Q 0, the water quality index C is less than C 0, the toxicity index I is less than I 0, and the total amount of pollutants W is less than the set value W 0, the total amount of toxic substances T is less than the set value T 0, then the tail water enters the receiving water body, otherwise it needs to enter the tail water treatment system for reprocessing.

[0029] The MBBR tank (2-5) needs to use activated sludge and wastewater circulation to domesticate sludge at the beginning of commissioning, and gradually domesticates according to the wastewater and sludge ratio from low to high, and domesticates for 2-4 days at each ratio, so that the microorganisms gradually adapt to the water quality and the microorganisms reproduce until the filler surface is covered with biofilm. In a specific embodiment, the activated sludge is first added, and the activated sludge is added at 30%-50% of the volume of the MBBR tank, and the activated sludge concentration is 4000-8000 mg / L, then wastewater is added for domestication, and gradually domesticated according to the wastewater and sludge ratio from low to high (in turn 0.5:1, 1:1, 1.5:1), and domesticated for 2-4 days at each ratio, so that the microorganisms gradually adapt to the water quality and the microorganisms reproduce until the filler surface is covered with biofilm.

[0030] Specifically, when the system C / N is insufficient, the supernatant of the sludge digestion tank is supplemented with backflow, and the required backflow flow is calculated according to formula 3:

[0031] (Formula 3)

[0032] Wherein, Q x : backflow flow, m 3 / s;

[0033] Q : system treatment flow, m 3 / s;

[0034] C 1: COD concentration in the anoxic tank, mg / L;

[0035] N 1: TN concentration in the anoxic tank, mg / L;

[0036] C 2: COD concentration in the digestion liquid, mg / L;

[0037] N 2: TN concentration in the digestion liquid, mg / L;

[0038] k : target C / N ratio, generally 20-25, dimensionless.

[0039] The supernatant of the sludge digestion tank is generated by the sludge discharge of the rotating microfilter (2-3), the sludge discharge of the secondary sedimentation tank (2-6) and the cooperative fermentation digestion of external sludge, and the main components are cellulose, protein, acetic acid, heavy metals and the like, and the COD concentration is about 3000-6000 mg / L, and the TN concentration is about 300-800 mg / L; the external sludge is aquaculture sediment or landfill leachate treatment sludge

[0040] Advantages: Compared with the prior art, the advantages of the present application are:

[0041] (1) The present application mainly aims at low sewage for layer-by-layer circulation treatment, realizes the modularization of treatment facilities, and effectively solves the problems of total amount of low sewage pollutant emission and toxic substance reduction safety emission.

[0042] (2) In view of the problem of large water quantity of low sewage, the present application adopts an ecological-biological strong combination treatment mode to ensure the purification efficiency of low sewage.

[0043] (3) According to different water qualities, the present application adopts different proportions of sludge wastewater ratio to domesticate and film treat microorganisms, strengthens the purification capacity of polyurethane filler pool, and realizes efficient purification treatment of tail water of sewage plant. BRIEF DESCRIPTION OF DRAWINGS

[0044] The above and / or other aspects of the present application will become apparent from the following detailed description of the application taken in conjunction with the accompanying drawings.

[0045] Figure 1 It is a process plan view of a low pollution water treatment modular device;

[0046] Figure 2 It is a sectional view a-a of a low pollution water treatment modular device;

[0047] Figure 3 It is a sectional view b-b of a low pollution water treatment modular device;

[0048] Figure 4 It is a sectional view c-c of a low pollution water treatment modular device;

[0049] Figure 5 It is a sectional view d-d of a low pollution water treatment modular device;

[0050] Figure 6 It is a principle view of a low pollution water treatment modular device;

[0051] Among them, 1-prewarning control system, 2-tail water treatment system, 3-receiving water body, 4-backflow system;

[0052] 1-1-flow and water quality prewarning device, 1-2-toxicity prewarning device;

[0053] 2-1-adjustment pond, 2-2-ecological pond, 2-3-rotary drum microfilter, 2-4-anoxic tank, 2-5-MBBR tank, 3-6-secondary sedimentation tank, 2-7-clean water tank, 2-8-sludge digestion tank;

[0054] 2-2-1-ecological floating island, 2-2-2-aquatic plant;

[0055] 2-4-1-Agitator, 2-4-2-Return pipe, 2-4-3-Anoxic tank outlet pipe;

[0056] 2-5-1-Sludge discharge pipe, 2-5-2-Flow guide tube, 2-5-3-MBBR tank inlet pipe. Detailed Implementation

[0057] The technical solution of the present invention is further described below through specific embodiments. The present invention focuses on a low-pollution water treatment system; therefore, the embodiments specifically illustrate the steps and methods of wastewater treatment.

[0058] Example 1

[0059] like Figures 1-6 The low-pollution water modular device shown includes four subsystems: an early warning control system (1), a tailwater treatment system (2), a receiving water body (3), and a return system (4).

[0060] The early warning control system (1) includes a flow and water quality early warning device (1-1) and a toxicity early warning device (1-2).

[0061] The wastewater treatment system (2) includes a regulating pond (2-1), an ecological pond (2-2), a rotary drum microfilter (2-3), an anoxic tank (2-4), an MBBR tank (2-5), a secondary sedimentation tank (2-6), and a clear water tank (2-7) connected in sequence. The rotary drum microfilter (2-3) and the secondary sedimentation tank (2-6) are respectively connected to the sludge digestion tank (2-8) to facilitate the discharge of treated sludge. The sludge digestion tank (2-8) is also connected to the anoxic tank (2-4) to supplement the carbon source.

[0062] The ecological pond (2-2) is equipped with ecological floating islands (2-2-1) and aquatic plants (2-2-2). The ecological floating island (2-2-1) includes a bed, a floating island carrier set on the bed, and floating island plants. The bed is made of PVC pipe, and the floating island carrier is tied with high-strength nylon fishing net. The floating island plants are a combination of round coin grass and pink green foxtail algae. The aquatic plants (2-2-2) are calamus, cattail, and canna.

[0063] The rotary drum microfilter (2-3) is located between the anoxic pond (2-4) and the ecological pond (2-2) and is used for the SS and COD filtration treatment of the effluent.

[0064] Figure 4 and Figure 5 The diagram shows the internal structure of the wastewater entering the anoxic tank (2-4). First, the wastewater is stirred by the agitator (2-4-1) to ensure that the wastewater and sludge are fully mixed. Then, the wastewater is discharged through the effluent pipe of the anoxic tank (2-4-3). Part of the wastewater and sludge mixture is recycled through the return pipe (2-4-2) to improve the denitrification effect.

[0065] The wastewater from the anoxic tank (2-4) enters the MBBR tank (2-5), and first, the wastewater enters the 2-5-2 flow guide cylinder through the 2-5-3-MBBR tank water inlet pipe for rectification and mixing, and the sludge in the MBBR tank (2-5) is discharged through the 2-5-1 sludge discharge pipe.

[0066] The residual sludge in the secondary sedimentation tank (2-6) is externally returned to the drum microfilter (2-3) through the return system (4), and is internally returned to the anoxic tank (2-4) from the secondary sedimentation tank (2-6).

[0067] The MBBR tank (2-5) is provided with a sludge discharge pipe (2-5-1), a flow guide cylinder (2-5-2), and an MBBR tank water inlet pipe (2-5-3), and the inside of the MBBR tank (2-5) is provided with porous gel suspension filler, which is polyurethane material, with a specific surface area of 2500-3500 m 2 / m 3 ; porosity ≥98%; reaction tank filling rate 15-30%; at the beginning of operation, active sludge and wastewater are circulated to acclimate the sludge, and the wastewater and sludge ratio is gradually acclimated from low to high, each ratio acclimation for 2-4 days, so that the microorganisms gradually adapt to the water quality and the microorganisms reproduce until the filler surface is covered with a biofilm. The completion of the biofilm formation time is 7-10 days; the service life is >10 years.

[0068] The acclimation steps are: first, adding active sludge, the active sludge is added at a concentration of 4000-8000 mg / L, and then wastewater is added for acclimation, and the wastewater and sludge ratio is gradually acclimated from low to high (wastewater and sludge ratio is 0.5:1, 1:1, 1.5:1).

[0069] The sludge digestion tank (2-8) is connected to the drum microfilter (2-3) and the secondary sedimentation tank (2-6) through a pipeline, facilitating the discharge of treated sludge, and the sludge digestion tank (2-8) is also connected to the anoxic tank (2-4), which can supplement the carbon source.

[0070] The method for treating tail water in a sewage plant using the above device is as follows:

[0071] Step 1) The tail water of the sewage plant enters the ecological pond (2-2) from the regulation pond (2-1) through a pipeline or the like, and at the same time, a micro-ecological purification agent (EM bacteria are used in this embodiment, and the dosage is 50-200 mg / L of sewage) is added into the ecological pond (2-3);

[0072] Step 2) The wastewater of the ecological pond (2-2) is pumped into the combined drum microfilter (2-3) by a water pump for SS and COD filtration treatment, and the treated sludge is discharged into the sludge digestion tank (2-8), and the mixed sludge is further digested in the sludge digestion tank (2-8), and the digested supernatant is returned to the anoxic tank (2-4) as a supplemental carbon source;

[0073] Step 3) After the wastewater is filtered by the drum microfilter (2-3), it enters the anoxic tank (2-4) and the MBBR tank (2-5) for aeration treatment to remove total nitrogen, COD, ammonia nitrogen and other pollutants. The water quality before and after purification is detected by the flow and water quality early warning device (1-1) (as shown in Table 1), and the internal reflux tail water quantity is determined according to the treatment efficiency of the pollutants, and the calculation formula is as formula 1:

[0074]

[0075] (Formula 1)

[0076] Note:

[0077] α: tail water purification efficiency;

[0078] R : external reflux ratio, generally controlled at (30-50%, which is the test summary data);

[0079] r : internal reflux ratio;

[0080] After calculation, take R=0.4, r=0.2, and re-enter the anoxic tank (2-4) through the reflux system (4) for secondary purification treatment.

[0081] Step 4) The tail water that does not enter the reflux system (4) passes through the MBBR tank (2-5) and enters the secondary sedimentation tank (2-6) reserved with coagulant, and after sedimentation, the sludge is discharged into the sludge digestion tank (2-8), and part of the sludge is discharged into the anoxic tank (2-4) through the reflux system (4) according to the external reflux ratio R=0.4 for three times purification treatment.

[0082] Step 5) Finally, the tail water enters the clear water tank (2-7) for disinfection treatment, and the flow and water quality early warning device (1-1) and the toxicity early warning device (1-2) check the tail water to determine whether the purification meets the standard, and the determination formula is as formula 2:

[0083] ; ; ; ; (Formula 2)

[0084] Note: COD concentration of the standard tail water and the discharge tail water, mg;

[0085] Q 0, Q : flow index of the standard tail water and the discharge tail water, m 3 / s;

[0086] I 0, I : toxicity index of the standard tail water and the discharge tail water, mg / m 3 ;

[0087] W 0, W : total pollutant emission of the standard tail water and the discharge tail water, mg;

[0088] T 0, T : total toxicity substance emission of the standard tail water and the discharge tail water, mg.

[0089] Generally, the index selection can be selected as: COD 50 mg / L, NH3-N 5.0 mg / L, TN 15.0 mg / L, I 0 The toxicity concentration is measured by the luminescent bacteria method, mg / L, and the toxicity emission limit value I0 follows the international standard ISO-11348-3.

[0090] It is determined that the effluent meets formula 2, and the tail water of the sewage plant can enter the receiving water body (3).

[0091] Through these steps, the purification of the tail water is completed.

[0092] Example 2

[0093] All the step conditions are the same as those in Example 1, only the environmental temperature is 5-15℃.

[0094] After the treatment process, the tail water purification conditions are shown in Table 2.

[0095]

[0096] The results show that the system still has high treatment efficiency at low temperature.

[0097] Example 3

[0098] All the step conditions are the same as those in Example 1, only the system C / N is 5;

[0099] When the system C / N is insufficient, the supernatant of the sludge digestion tank is supplemented, and the required reflux flow is calculated according to formula 3:

[0100] (Formula 3)

[0101] Note: Q x : reflux flow, m 3 / s;

[0102] Q : system processing flow, take 0.1 m 3 / s;

[0103] C 1: COD concentration in the anoxic tank, take 300 mg / L;

[0104] N 1: TN concentration in the anoxic tank, take 60 mg / L;

[0105] C 2: COD concentration in the digestion liquid, take 5000 mg / L;

[0106] N 2: TN concentration in the digestion liquid, take 300 mg / L;

[0107] k : target C / N ratio, take 20, dimensionless.

[0108] The reflux flow is calculated Q x = 0.09 m 3 / s, and the sewage after carbon source compensation can achieve the treatment effect in Embodiment 1.

[0109] The above is the preferred embodiment of the present application, it should be pointed out that, for the ordinary skilled in the art, without departing from the principles of the present application, can also make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for operating a low pollution water high efficient bioaugmented treatment and toxicity reduction system, characterized in that, Comprising the following steps: Step 1: The tail water of the sewage plant enters the ecological pond (2-2) from the adjusting pond (2-1) through a pipeline or the like, and a micro-ecological purification agent is added into the ecological pond (2-2) at the same time, wherein the ecological pond (2-2) is provided with an ecological floating island (2-2-1) and aquatic plants (2-2-2); Step 2: The wastewater in the ecological pond (2-2) is pumped into the rotary drum micro-filter (2-3) by a water pump for SS and COD filtration treatment, and the treated sludge is discharged into a sludge digestion tank (2-8) for further digestion treatment, and the digestion supernatant is returned to the anoxic tank (2-4) as a supplemental carbon source; Step 3: After the wastewater is filtered by the rotary drum micro-filter (2-3), it enters the anoxic tank (2-4) and the MBBR tank (2-5) for aeration treatment to remove total nitrogen, COD and ammonia nitrogen pollutants, respectively; the flow and water quality early warning device (1-1) detects the water quality before and after purification, and the internal reflux tail water quantity is determined according to the treatment efficiency of the pollutants, and the calculation formula is as shown in formula 1: (Formula 1) Note: α: tail water purification efficiency; R : external reflux ratio, controlled at (30-50%); r : internal reflux ratio; According to the calculation result, part of the tail water reenters the anoxic tank (2-4) through the reflux system (4) for secondary purification treatment; Step 4: The tail water not entering the reflux system (4) passes through the MBBR tank (2-5) and enters the secondary sedimentation tank (2-6) reserved with a coagulant, and after sedimentation, the sludge is discharged into the sludge digestion tank (2-8); the flow and water quality early warning device (1-1) detects the water quality before and after purification, and part of the sludge is put into the anoxic tank (2-4) through the reflux system (4) for tertiary purification treatment according to the external reflux ratio R; Step 5: Finally, the tail water enters the clean water tank (2-7) for disinfection treatment; the flow and water quality early warning device (1-1) and the toxicity early warning device (1-2) check the tail water to determine whether the purification meets the standard; if it meets the standard, the tail water of the sewage plant can enter the receiving water body (3); otherwise, it needs to be treated again through the reflux system (4) and the tail water treatment system (2).

2. The method of claim 1, wherein, In step (5), the determination formula whether it meets the standard is as shown in formula (2): ； ； ； ； ； (Formula 2) Note: COD concentration in the standard effluent, mg; Q 0、 Q : flow rate of the compliance effluent, m 3 / s; I 0、 I : Toxicity index of compliance effluent, mg / m 3 ; W 0、 W : total pollutant discharge amount of the standard tail water and the discharge tail water, mg; T 0、 T : Total amount of toxic substances discharged in the standard effluent and the discharge effluent, mg.

3. The method of claim 1, wherein, The tail water of the sewage treatment plant is detected by the flow and water quality early warning device (1-1), the flow index Q Less than Q 0, the water quality index is detected C Less than C 0, the toxicity index is detected I Less than I 0, and the total amount of pollutants discharged W Less than the set value W 0, the total amount of toxic substances discharged T Less than the set value T 0, the tail water enters the receiving water body, otherwise it needs to enter the tail water treatment system for further treatment.

4. The method of claim 1, wherein, When the MBBR tank (2-5) is just put into operation, the activated sludge and wastewater are circulated to acclimate the sludge, and the wastewater and sludge ratio is gradually acclimated from low to high, and each ratio is acclimated for 2-4 days, so as to gradually adapt the water quality for the microorganisms and make the microorganisms reproduce until the filler surface is covered with a biofilm.

5. The method of claim 1, wherein, When the system C / N is insufficient, the supernatant of the sludge digestion tank is supplemented, and the required reflux flow is calculated according to formula 3: (Formula 3) wherein, Q x : reflux flow rate, m 3 / s; Q : system handles traffic, m 3 / s; C 1: COD concentration in the anoxic tank, mg / L; N 1: TN concentration in the anoxic tank, mg / L; C 2: COD concentration in the digestive juice, mg / L; N 2: TN concentration in digestive juice, mg / L; k : Target C / N ratio, dimensionless, 20-25 The supernatant of the sludge digestion tank is generated by the sludge discharge of the rotary drum micro-filter (2-3), the sludge discharge of the secondary sedimentation tank (2-6) and the cooperative fermentation digestion of external sludge, and the main components are cellulose, protein, acetic acid, heavy metals and the like, with a COD concentration of 3000-6000 mg / L and a TN concentration of 300-800 mg / L; the external sludge is aquaculture bottom mud or landfill leachate treatment sludge.

6. A low pollution water high efficient bioaugmented treatment and toxicity reduction system for implementing the method according to any one of claims 1-5, comprising an early warning control system (1), a tail water treatment system (2), a receiving water body (3) and a backflow system (4), characterized in that, The tail water treatment system (2) comprises a regulating pond (2-1), an ecological pond (2-2), a drum microfilter (2-3), an anoxic tank (2-4), an MBBR tank (2-5), a secondary sedimentation tank (2-6) and a clear water tank (2-7) connected in sequence; the drum microfilter (2-3) and the secondary sedimentation tank (2-6) are connected with a sludge digestion tank (2-8) respectively, and the sludge digestion tank (2-8) is also connected with the anoxic tank (2-4).

7. The system of claim 6, wherein, The ecological pond (2-2) is provided with an ecological floating island (2-2-1) and aquatic plants (2-2-2), the ecological floating island (2-2-1) comprises a bed body, a floating island carrier arranged on the bed body and floating island plants; the bed body is made of a PVC pipe, the floating island carrier is bound by a high-strength nylon fishing net; the floating island plants are in the form of a combination of round coin grass and Myriophyllum propinquum; the aquatic plants (2-2-2) are Acorus calamus, Typha angustifolia and Canna indica.

8. The system of claim 6, wherein, The MBBR tank (2-5) is provided with a sludge discharge pipe (2-5-1), a flow guide cylinder (2-5-2) and an MBBR tank water inlet pipe (2-5-3), and a porous gel suspension filler is arranged in the MBBR tank (2-5); the porous gel suspension filler is made of polyurethane material, has a specific surface area of 2500-3500 m2 / m3, a porosity of greater than or equal to 98%, and a reaction tank filling rate of 15-30%; the active sludge is used to complete the film formation on the porous gel suspension filler for 7-10 days; and the service life is greater than 10 years.

9. The system of claim 6, wherein, The early warning control system (1) comprises a flow and water quality early warning device (1-1) and a toxicity early warning device (1-2); the early warning devices are connected to early warning monitoring points through sensors; the flow and water quality early warning device (1-1) can detect flow and conventional water quality data simultaneously; and the toxicity early warning device (1-2) is used for monitoring the content change of characteristic pollutants.

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