A method and apparatus for combined treatment of landfill leachate and domestic sewage

Abstract

The application relates to a method and device for jointly treating landfill leachate and domestic sewage, belonging to the technical field of sewage treatment, which mainly comprises a domestic sewage treatment system, a landfill leachate treatment system, a joint treatment system and a sludge treatment system. Organic matters and phosphates are removed and ammonia nitrogen is reserved after the domestic sewage is treated by the domestic sewage treatment system; organic matters and phosphates are removed and ammonia nitrogen is converted into nitrous nitrogen after the landfill leachate is treated by the landfill leachate treatment system. Then, the effluent of the domestic sewage treatment system and the effluent of the landfill leachate treatment system are mixed into the joint treatment system, nitrogen is removed through an anaerobic ammonia oxidation unit, the effluent of the anaerobic ammonia oxidation unit is treated through an AO-MBR enhanced denitrification unit, and the hydrolysate generated by the sludge treatment system is used as a carbon source for denitrification, so that the removal of nitrogen and organic matters is further intensified. The application has low operation cost, low sludge yield and good effluent water quality.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically to a method and apparatus for the combined treatment of landfill leachate and domestic sewage. Background Technology

[0002] With the rapid development of my country's economy and the ongoing urbanization process, the amount of urban domestic waste generated, collected, and treated has been increasing year by year. According to research, each ton of urban domestic waste generates 0.05-0.2 tons of leachate during its transfer and treatment. In 2020, the amount of leachate generated by various urban domestic waste facilities in my country reached approximately 50 million tons. Leachate is characterized by its pungent odor, high content of organic matter and ammonia nitrogen, nutrient imbalance, and wide range of water quality variations. It also has a complex composition, containing various trace pollutants such as heavy metals, endocrine disruptors, pesticides, plasticizers, chlorinated and halogenated organic compounds, etc., exhibiting biotoxicity. If left untreated, it can cause serious environmental pollution problems. Currently, great importance is attached to the treatment and disposal of landfill leachate. In 2008, a new emission standard, "Pollution Control Standard for Municipal Solid Waste Landfills" (GB 16889-2008), was promulgated, imposing stricter emission standards for TN, TP, and ammonia nitrogen, further increasing the difficulty of leachate treatment. At present, landfill leachate is mainly treated by setting up separate wastewater treatment plants. The treatment process mainly adopts "pretreatment + biological treatment + advanced treatment". Due to the influence of water quality, there are many problems in treating landfill leachate separately. (1) In order to reduce the biological toxicity of pollutants, a large amount of effluent is generally required for dilution, which increases the operating cost. (2) The biological treatment section requires high-efficiency denitrification capacity, which requires high-energy aeration and a large amount of external carbon source. (3) The advanced treatment section mostly adopts high-cost treatment processes such as nanofiltration and reverse osmosis.

[0003] In recent years, with the large-scale construction of urban sewage treatment plants, as of 2020, there were a total of 4,326 urban and county sewage treatment plants, of which 2,618 were urban sewage treatment plants. The annual sewage treatment volume reached 5,572,782 cubic meters, and the sewage treatment rate reached 97.53%, effectively solving the environmental problems caused by urban sewage. However, as the national standards for effluent discharge become increasingly stringent, the operating costs of urban sewage treatment plants using traditional treatment processes are constantly increasing in order to meet the requirements of national and local discharge standards. Among them, the key issues are energy consumption and chemical consumption: (1) The aerobic treatment section of urban sewage treatment plants requires aeration and oxygenation to meet the requirements for pollutant removal, and a large amount of residual sludge needs to be treated and disposed of. The energy consumption required for aeration and sludge treatment accounts for 60% to 80% of the total energy consumption of the sewage treatment plant; (2) More than 70% of urban sewage in China has a low carbon-nitrogen ratio, and a large amount of external carbon sources are required to meet the requirements of the discharge standards for nitrogen and phosphorus effluent.

[0004] In summary, current landfill leachate and domestic sewage treatment both suffer from high costs and unsustainability. The introduction of anaerobic ammonium oxidation (ANAO) technology makes low-energy, sustainable sewage treatment possible. This process first oxidizes a portion of ammonia nitrogen into nitrite nitrogen through short-cut nitrification, and then oxidizes the remaining ammonia nitrogen with the nitrite nitrogen, thus achieving wastewater denitrification. Compared to traditional nitrification-denitrification biological denitrification processes, ANAO autotrophic denitrification technology can save 60% of aeration volume, consume 100% of organic carbon sources, and produce less sludge, thereby reducing direct energy consumption and operating costs. However, the stable achievement of short-cut nitrification is a bottleneck for the widespread application of ANAO technology. Previous studies have shown that short-cut nitrification can be achieved by using free ammonia (FA) and free nitrite (FNA) to inhibit NOB activity. However, because domestic sewage has a lower ammonia nitrogen concentration compared to landfill leachate with its higher ammonia nitrogen concentration, it cannot produce a higher concentration of FA or FNA to inhibit NOB growth, making stable short-cut nitrification difficult to achieve. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a method and apparatus for the combined treatment of landfill leachate and domestic sewage, which can treat domestic sewage and landfill leachate efficiently and with low consumption.

[0006] The technical solution of this invention is:

[0007] An apparatus for the combined treatment of landfill leachate and domestic sewage is characterized by comprising a domestic sewage treatment system (1), a landfill leachate treatment system (2), a combined treatment system (3), and a sludge treatment system (4) that are interconnected.

[0008] The domestic sewage treatment system (1) includes an interconnected domestic sewage storage tank (11) and an AO biological phosphorus and carbon removal unit I (12). The AO biological phosphorus and carbon removal unit I (12) is equipped with an influent pump I (121), an AO biological phosphorus and carbon removal tank I (122), a secondary sedimentation tank I (123), a mixer I (124), a blower I (125), an aerator I (126), a sludge return pump I (127), and a waste sludge pump I (128).

[0009] The landfill leachate treatment system (2) includes interconnected landfill leachate storage tank (21), UASB treatment unit (22), intermediate tank I (23), AO biological phosphorus and carbon removal unit II (24), intermediate tank II (25), and short-cut nitrification unit (26); the UASB treatment unit (22) is equipped with influent pump II (221), UASB tank (222), and excess sludge pump II (223); the AO biological phosphorus and carbon removal unit II (24) is equipped with influent pump III (241), AO biological phosphorus removal unit II (243), and AO biological phosphorus removal unit II (244). Carbon removal tank II (242), secondary sedimentation tank II (243), agitator II (244), blower II (245), aerator II (246), sludge return pump II (247), and waste sludge pump III (248); the short-cut nitrification unit (26) is equipped with influent pump IV (261), short-cut nitrification tank (262), secondary sedimentation tank III (263), blower III (264), aerator III (265), sludge return pump III (266), and waste sludge pump IV (267);

[0010] The combined treatment system (3) includes an interconnected mixing tank (31), an anaerobic ammonia oxidation unit (32), an intermediate tank III (33), an AO-MBR enhanced denitrification unit (34), and an effluent tank (35); the anaerobic ammonia oxidation unit (32) is equipped with an influent pump V (321), an anaerobic ammonia oxidation tank (322), and a waste sludge pump V (323); the intermediate tank III (33) is equipped with a wastewater return pump (331); the AO-MBR enhanced denitrification unit (34) is equipped with an influent pump VI (341), an AO-MBR enhanced denitrification tank (342), a mixer III (343), a blower IV (344), an aerator IV (345), an MBR membrane unit (346), a sludge return pump IV (347), a permeate pump (348), and a waste sludge pump VI (349);

[0011] The sludge treatment system (4) includes a sludge mechanical thickening room (41), a sludge transfer pump (42), a sludge hydrolysis tank (43), a sludge hydrolysate addition pump (44), a NaOH addition system (45), and a supernatant return pump (46).

[0012] The domestic sewage storage tank (11) is connected to the inlet of the AO biological phosphorus removal and decarbonization tank I (122) via the inlet pump I (121). The outlet of the AO biological phosphorus removal and decarbonization tank I (122) is connected to the inlet of the secondary sedimentation tank I (123). A stirrer I (124) is installed in the anaerobic section at the front of the AO biological phosphorus removal and decarbonization tank I (122), and an aerator I (126) is installed in the aerobic section at the rear of the AO biological phosphorus removal and decarbonization tank I (122). Connected to blower I (125), the sludge outlet of secondary sedimentation tank I (123) is connected to the anaerobic section in front of AO biological phosphorus removal and decarbonization tank I (122) via sludge return pump I (127). At the same time, the sludge outlet of secondary sedimentation tank I (123) is connected to the sludge mechanical thickening room (41) in sludge treatment system (4) via excess sludge pump I (128). The outlet of secondary sedimentation tank I (123) is connected to the mixing tank (31) in combined treatment system (3).

[0013] The landfill leachate storage tank (21) is connected to the UASB tank (222) via inlet pump II (221), and the outlet of the UASB tank (222) is connected to the intermediate tank I (23). The intermediate tank I (23) is connected to the inlet of the AO biological phosphorus and carbon removal tank II (242) via inlet pump III (241), and the outlet of the AO biological phosphorus and carbon removal tank II (242) is connected to the inlet of the secondary sedimentation tank II (243). The anaerobic section at the front is equipped with a stirrer II (244), and the aerobic section at the rear of the AO biological phosphorus removal and decarbonization tank II (242) is equipped with an aerator II (246). The aerator II (246) is connected to the blower II (245). The sludge outlet of the secondary sedimentation tank II (243) is connected to the anaerobic section of the AO biological phosphorus removal and decarbonization tank II (242) through a sludge return pump II (247). The outlet of the secondary sedimentation tank II (243) is connected to the intermediate tank II (25). Tank II (25) is connected to the inlet of the short-cut nitrification tank (262) via inlet pump IV (261). The outlet of the short-cut nitrification tank (262) is connected to the inlet of the secondary sedimentation tank III (263). An aerator III (265) is installed in the short-cut nitrification tank (262), and the aerator III (265) is connected to the blower III (264). The sludge outlet of the secondary sedimentation tank III (263) is connected to the short-cut nitrification tank (262) via sludge return pump III (266). The outlet of the secondary sedimentation tank III (263) is connected to the mixing tank (31) in the combined treatment system (3); the sludge outlet of the UASB tank (222), the sludge outlet of the secondary sedimentation tank II (243), and the sludge outlet of the secondary sedimentation tank III (263) are respectively connected to the sludge mechanical thickening room (41) in the sludge treatment system (4) through the excess sludge pump II (223), the excess sludge pump III (248), and the excess sludge pump IV (267);

[0014] The mixing tank (31) is connected to the inlet of the anaerobic ammonia oxidation tank (322) via the inlet pump V (321). The outlet of the anaerobic ammonia oxidation tank (322) is connected to the intermediate tank III (33). The intermediate tank III (33) is connected to the intermediate tank II (25) via the wastewater return pump (331). The intermediate tank III (33) is connected to the inlet of the AO-MBR enhanced denitrification tank (342) via the inlet pump VI (341). The anoxic section at the front of the AO-MBR enhanced denitrification tank (342) is equipped with a stirrer III (343). The aerobic section at the rear of the AO-MBR enhanced denitrification tank (342) is equipped with an aerator IV (345). The aerator IV (345) is connected to the blower IV. (344) Connecting, an MBR membrane unit (346) is installed in the aerobic section of the AO-MBR enhanced denitrification tank (342). The MBR membrane unit (346) is connected to the effluent tank (35) through a product water pump (348). The aerobic section in the AO-MBR enhanced denitrification tank (342) is connected to the anoxic section in the AO-MBR enhanced denitrification tank (342) through a sludge return pump IV (347). The sludge outlet end of the anaerobic ammonia oxidation tank (322) and the sludge outlet end of the AO-MBR enhanced denitrification tank (342) are respectively connected to the sludge mechanical thickening room (41) in the sludge treatment system (4) through a waste sludge pump V (323) and a waste sludge pump VI (349).

[0015] The sludge mechanical thickening room (41) is connected to the secondary sedimentation tank (123), UASB tank (222), secondary sedimentation tank II (248), secondary sedimentation tank III (267), anaerobic ammonia oxidation tank (322), and AO-MBR enhanced denitrification tank (349) via waste sludge pumps I (128), II (223), III (243), IV (267), V (323), and VI (349), respectively. 2) Sludge outlet connection; The sludge mechanical thickening room (41) is connected to the sludge hydrolysis tank (43) through the sludge transfer pump (42), the sludge hydrolysis tank (43) is connected to the anoxic section of the AO-MBR enhanced denitrification tank (342) through the sludge hydrolysis liquid addition pump (44), the NaOH addition system (45) is connected to the sludge hydrolysis tank (43), and the sludge mechanical thickening room (41) returns the supernatant of the sludge thickening room to the intermediate tank III (33) through the supernatant return pump (46);

[0016] The method for jointly treating landfill leachate and domestic sewage using the above-mentioned apparatus includes the following processes:

[0017] (1) Start-up and operation of the domestic sewage treatment system: During the start-up period, activated sludge from the municipal sewage treatment plant was inoculated into the AO biological phosphorus and carbon removal tank I (122). The activated sludge concentration was 3000-4000 mg / L. After aeration for 2-3 days, domestic sewage was introduced. The sludge load was 0.2-0.3 kg BOD5 / (kg MLSS.d), dissolved oxygen was controlled at 2-3 mg / L, sludge return ratio was 100%, sludge age was 5-7 days, COD removal rate reached more than 60% under the current sludge load, TP removal rate reached more than 50%, and ammonia nitrogen oxidation rate was less than 5%. The system was stable for more than 7 days, and the system was successfully started up. During operation, domestic sewage was introduced from the domestic sewage storage tank into the AO biological phosphorus and carbon removal tank via influent pump I (121). In the anaerobic section of carbon tank I (122), activated sludge is mixed with activated sludge returned from secondary sedimentation tank I (123) under the action of stirrer I. Polyphosphate-accumulating bacteria in activated sludge absorb organic matter to release phosphorus. Then, the sludge mixture enters the aerobic section to complete the phosphorus absorption reaction and remove organic matter. At the same time, by controlling the sludge load at 0.2-0.3 kg BOD5 / (kg MLSS.d) and the sludge age at 5-7 days, the growth of nitrifying bacteria is inhibited, and the oxidation rate of ammonia nitrogen is controlled within 5%. After the mixture treated in the aerobic section enters the secondary sedimentation tank I (123) for sedimentation for 2-3 hours, the supernatant containing ammonia nitrogen enters the mixing tank (31). The sludge return ratio of secondary sedimentation tank I (123) is controlled at 50-100%, and the excess sludge is discharged to the mechanical sludge thickening room (41) by the excess sludge pump I (128).

[0018] (2) Start-up and operation of landfill leachate treatment system: 1) Start-up of UASB treatment unit: Inoculate granular sludge into UASB tank (222) at a rate of 10-15 kg VSS / m³. 3 By gradually increasing the leachate flow rate, the volumetric loading rate is set at 3 kg COD / m³. 3 .d、5kgCOD / m 3 .d、8kgCOD / m 3 The COD removal rate is gradually increased. Once the COD removal rate reaches over 60% at the current volumetric load, the rate is increased to the next volumetric load until it reaches 8 kg COD / m³. 3.d, UASB treatment unit started successfully; 2) AO biological phosphorus and carbon removal unit II started: Inoculate activated sludge from the municipal wastewater treatment plant into AO biological phosphorus and carbon removal tank II (242), the activated sludge concentration is 3000-4000 mg / L, add effluent from UASB unit and aerate for 2-3 days, then start continuous influent, gradually increase the water volume, the sludge load is 0.2 kg BOD5 / (kg MLSS.d), 0.4 kg BOD5 / (kg MLSS.d), 0.6 kg BOD5 / (kg MLSS.d), 0.6 kg BOD5 / (kg MLSS.d), 0.6 kg BOD5 / (kg MLSS.d), 0.4 ...5 kg BOD5 / (kg MLSS.d), 0.4 kg BOD5 / (kg MLSS.d), 0.5 kg BOD5 / (kg MLSS.d), 0.5 kg BOD5 / (kg MLSS.d), 0.5 kg BOD5 / (kg MLSS.d), 0.5 kg BOD5 / (kg MLSS.d), 0.5 kg BOD5 / (kg MLSS.d), 0.5 kg BOD5 / (kg MLSS.d), 0.5 kg BOD5 / (kg MLSS.d), 0 The sludge load is gradually increased in three gradients (D5 / (kgMLSS.d)). Dissolved oxygen is controlled at 2-3 mg / L, sludge return ratio is 100%, sludge age is 4-5 days, and when the COD removal rate reaches over 60% and the TP removal rate reaches over 50% under the current sludge load and operates stably for over 7 days, the load is increased to the next sludge load gradient until the sludge load reaches 0.6 kg BOD5 / (kgMLSS.d). Under this 0.6 kg BOD5 / (kgMLSS.d) sludge load, the COD removal rate reaches over 60%. The system is considered successfully started when the TP removal rate reaches over 50%, the ammonia nitrogen oxidation rate is less than 5%, and the system has been running stably for over 7 days; 3) Start-up of the short-cut nitrification unit: Inoculate activated sludge from the municipal wastewater treatment plant into the short-cut nitrification tank (262), with an activated sludge concentration of 3000-4000 mg / L. After aeration for 2-3 days, start adding AO biological phosphorus and carbon removal unit II effluent. Control the total nitrogen load at 0.04-0.05 kgTN / (kgMLSS.d) and dissolved oxygen at 1.5-3 mg / L by controlling the influent flow rate. The sludge recirculation ratio is 300-400%, the sludge age is 10-15 days, and the system is successfully started when the ammonia nitrogen removal rate reaches 80%, the nitrite accumulation rate reaches 85%, and the system has been running stably for more than 7 days. After the UASB treatment unit, AO biological phosphorus and carbon removal unit II and short-cut nitrification unit are all successfully started, the three units are connected in series. The landfill leachate enters the UASB tank (222) from the landfill leachate storage tank (21) through the influent pump II (221). The volumetric loading of the UASB is kept at 6-8 kg COD / m³ by controlling the influent flow rate. 3After the removal of easily degradable organic matter from the landfill leachate in the UASB, the effluent enters intermediate tank I (23). The water in intermediate tank I (23) is pumped by inlet pump III (241) into the anaerobic section of AO biological phosphorus and carbon removal tank II (242). Under the action of stirrer II, it mixes with the activated sludge returned from secondary sedimentation tank II (243). The activated sludge absorbs organic matter and releases phosphorus. Then, the sludge mixture enters the aerobic section to complete the phosphorus absorption reaction and remove organic matter. During operation, the process is controlled by... The sludge loading rate is 0.5-0.6 kg BOD5 / (kg MLSS.d), the sludge age is 4-5 days, the growth of nitrifying bacteria is inhibited, and the ammonia nitrogen oxidation rate is controlled within 5%. Then, the aerobic mixed liquor enters the secondary sedimentation tank II (243) for sedimentation for 2-3 hours. The ammonia nitrogen-containing supernatant then enters the intermediate tank II (25). The sludge return ratio of the secondary sedimentation tank II (243) is controlled at 50-100%. The effluent from the anaerobic ammonia oxidation tank, i.e., the intermediate tank III (33), is pumped through the sewage return pump (331). In the water and landfill leachate treatment system, the effluent from the AO biological phosphorus and carbon removal tank II is mixed in intermediate tank II (25) at a volume ratio of 3-4:1. The ammonia nitrogen concentration in intermediate tank II (25) is controlled at 300-400 mg / L. The wastewater in intermediate tank II is pumped into the short-cut nitrification tank (262) by influent pump IV (261). The total nitrogen load in the short-cut nitrification tank (262) is controlled at 0.04-0.05 kgTN / (kgMLSS.d), and the dissolved oxygen is 1.5-3 m³ / kg. g / L, sludge return ratio 100-200%, sludge age 10-15d, after the ammonia nitrogen in the mixed liquor is converted into nitrite nitrogen in the short-cut nitrification tank (262), it enters the secondary sedimentation tank III (263) for sedimentation for 2-3h, and then the supernatant enters the mixing tank (31); the excess sludge from the UASB tank (222), secondary sedimentation tank II (243) and secondary sedimentation tank III (263) enters the sludge mechanical thickening room (41) through excess sludge pump II, excess sludge pump III and excess sludge pump IV respectively.

[0019] (3) Start-up and operation of the combined treatment system: 1) Start-up of the anaerobic ammonia oxidation unit: Inoculate the packing material with a relative abundance of anaerobic ammonia oxidizing bacteria greater than 10%, and the packing material filling ratio is 20-30%; First, start-up is carried out using nitrogen-containing wastewater prepared with tap water, with ammonia nitrogen concentration of 60 mg / L, nitrite nitrogen concentration of 80 mg / L, and hydraulic retention time of 12-15 h. When the TN removal rate reaches more than 80% and is maintained for more than 7 days, the next stage is entered; The next stage is: to mix the nitrogen-containing wastewater and the water in the mixing tank (31) according to the requirements of the mixing tank (31). The anaerobic ammonia oxidation unit was started by mixing the influent in volume ratios of 2:1, 1:1, 1:2, and 0:1. The hydraulic retention time of the system was 12 hours. After the TN removal rate reached more than 70% and the system operated stably for 7 days, the proportion of water in the mixing tank in the influent was gradually increased until all the influent was water from the mixing tank, and the system was successfully started. 2) Start-up of the AO-MBR enhanced denitrification unit: Activated sludge from the municipal wastewater treatment plant was inoculated into the AO-MBR enhanced denitrification tank (342) with an activated sludge concentration of 5%. After adding 000-6000 mg / L of anaerobic ammonia oxidation unit effluent and allowing it to aerate for 2-3 days, continuous influent is introduced. The sludge loading is gradually increased according to four sludge loading gradients: 0.01 kg TN / (kg MLSS.d), 0.02 kg TN / (kg MLSS.d), 0.03 kg TN / (kg MLSS.d), and 0.04 kg TN / (kg MLSS.d). Dissolved oxygen is controlled at 2-3 mg / L, and the internal recirculation ratio is 50-100%. Ammonia nitrogen removal under the current sludge loading is achieved. When the sludge loading rate reaches 80% or higher and operates stably for more than 7 days, the sludge loading is increased to the next sludge loading gradient until the sludge loading reaches 0.04 kgTN / kg (MLSS.d), indicating successful unit startup. After the successful startup of the anammox unit and the AO-MBR enhanced denitrification unit, the two units are connected in series. Water in the mixing tank (31) enters the anammox tank (322) via the influent pump V (321). The influent flow rate is adjusted to make the volumetric loading of the anammox tank 0.2-0.3 kgTN / (m³) 3.d), anaerobic ammonia-oxidizing bacteria utilize ammonia nitrogen and nitrite nitrogen in the water of the mixing tank (31) to carry out anaerobic ammonia oxidation reaction to remove nitrogen, and the effluent enters the intermediate tank III (33); at the same time, the supernatant of the sludge mechanical thickening room (41) is also returned to the intermediate tank III (33); due to insufficient anaerobic ammonia oxidation reaction, or an uncoordinated ratio of ammonia nitrogen and nitrite nitrogen, ammonia nitrogen, nitrite nitrogen and nitrite nitrogen may be present in the wastewater of the intermediate tank III (33); part of the wastewater in the intermediate tank III enters the intermediate tank II (25) through the wastewater return pump (331) to dilute the concentration of ammonia nitrogen in the effluent of the AO biological phosphorus and carbon removal unit II to 300-400 mg / L, and the other part of the intermediate tank III enters the anoxic section of the AO-MBR enhanced denitrification tank through the influent pump VI (341); under the action of the stirrer III, the activated sludge utilizes Nitrate and nitrite nitrogen in the sludge returned by intermediate tank III (33) and internal reflux mixed liquor, i.e., sludge return pump (347), and carbon source in sludge hydrolysate added by sludge hydrolysate addition pump (44) are used for denitrification. Then the mixed liquor enters the aerobic section for further removal of ammonia nitrogen and organic matter, and is finally filtered by the MBR membrane unit and discharged into the effluent tank. During operation, the activated sludge concentration in the AO-MBR enhanced denitrification tank (342) is 5000-6000 mg / L, the sludge nitrogen load is controlled at 0.03-0.04 kgTN / (kgMLSS.d), the HRT in the anoxic section is 2-3 h, the HRT in the aerobic section is 4-6 h, the sludge age is 20-25 d, the dissolved oxygen is controlled at 2-3 mg / L, the sludge return ratio is 100-150%, and the MBR membrane flux is 40-50 L / m 2 The excess sludge from the anaerobic ammonia oxidation tank (322) and the AO-MBR enhanced denitrification tank (342) is discharged to the sludge mechanical thickening room via excess sludge pump V (323) and excess sludge pump VI (349), respectively.

[0020] (4) Start-up and operation of the sludge treatment system: Start-up of the sludge hydrolysis tank: After the remaining sludge of the entire system is concentrated in the sludge mechanical thickening chamber (41), it is injected into the sludge hydrolysis tank (43) by the sludge transfer pump (42) until it is full. The concentration of the concentrated sludge in the sludge hydrolysis tank (43) is 10000-15000 mg / L. NaOH is added to the sludge hydrolysis tank by the NaOH dosing system to control the fermentation pH value at 10±0.5. The sludge is fermented in a closed system for 6-8 days. Then, 1 / 8 to 1 / 6 of the fermented sludge volume of the sludge hydrolysis tank is discharged every day, and the same volume of concentrated sludge is introduced at the same time. The NaOH dosing system controls the pH value of the sludge hydrolysis tank at 10±0.5. When the acid production of the sludge reaches 200-300 mg (COD) / g (VSS) and stabilizes for 10 days, the system Start-up successful; After successful start-up, the excess sludge discharged from the domestic sewage treatment system, landfill leachate treatment system and combined treatment system enters the sludge mechanical thickening room for thickening. The supernatant in the mechanical thickening room (41) is returned to the intermediate water tank III (33) by the supernatant return pump (46). The sludge hydrolysis liquid addition pump continuously draws hydrolyzed sludge from the sludge hydrolysis tank (43) every day and sends it to the anoxic section of the AO-MBR enhanced denitrification tank (342). The volume drawn every day is 1 / 8 to 1 / 6 of the volume of the sludge hydrolysis tank. Then, the same volume of thickened excess sludge is sent to the sludge hydrolysis tank (43) once by the sludge transfer pump (42). The sludge retention time is 6-8 days. At the same time, the NaOH addition system adds NaOH to the sludge fermentation tank to control the pH value of the entire fermentation process at 10±0.5.

[0021] The operation of the aforementioned domestic sewage treatment system, landfill leachate treatment system, combined treatment system, and sludge treatment system can occur simultaneously. That is, the materials used in the operation of any one of these four systems are the same materials used in the operation of the other three systems.

[0022] This invention couples domestic sewage treatment and landfill leachate treatment into one system, and has the following characteristics and advantages:

[0023] 1. By utilizing the high ammonia nitrogen concentration in landfill leachate, which makes short-cut nitrification relatively easy, nitrite nitrogen is provided for anaerobic ammonia oxidation, thus solving the problems of unstable short-cut nitrification of domestic sewage and difficulty in obtaining nitrite nitrogen from anaerobic ammonia oxidation treatment of domestic sewage.

[0024] 2. By utilizing the characteristics of balanced nutrients and low pollutant concentration in domestic sewage, the biotoxicity of landfill leachate is reduced and the problem of nutrient imbalance in landfill leachate treatment is solved.

[0025] 3. The combined treatment system produces low sludge output because it ferments the residual sludge from both the domestic sewage treatment system and the landfill leachate treatment system, resulting in a low overall sludge output.

[0026] 4. The denitrification effect of the system is enhanced by utilizing the carbon source generated by sludge fermentation, which reduces the cost of adding carbon source.

[0027] 5. An AO-MBR enhanced denitrification unit was installed to further treat the effluent from the anaerobic ammonia oxidation unit, ensuring that the effluent meets the standards. Attached Figure Description

[0028] Figure 1 Structural diagram of the present invention

[0029] 1-Domestic wastewater treatment system; 2-Landfill leachate treatment system; 3-Combined treatment system; 4-Sludge treatment system; 11-Domestic wastewater storage tank; 12-AO biological phosphorus and carbon removal unit I; 121-Inlet pump I; 122-AO biological phosphorus and carbon removal tank I; 123-Secondary sedimentation tank I; 124-Agitator I; 125-Blower I; 126-Aerator I; 127-Sludge return pump I; 128-Excess sludge pump I; 21-Landfill leachate storage tank; 22-UAS B Treatment Unit; 23-Intermediate Tank I; 24-AO Biological Phosphorus and Carbon Removal Unit II; 25-Intermediate Tank II; 26-Short-cut Nitrification Unit; 221-Influent Pump II; 222-UASB Tank; 223-Excess Sludge Pump II; 241-Influent Pump III; 242-AO Biological Phosphorus and Carbon Removal Tank II; 243-Secondary Settling Tank II; 244-Agitator II; 245-Blower II; 246-Aerator II; 247-Sludge Return Pump II; 248-Excess Sludge Pump III; 261-Influent Pump IV; 262-Short-cut Nitrification Tank; 263-Secondary Settling Tank III; 264-Blower III; 265-Aeration Head III; 266-Sludge Return Pump III; 267-Residue Sludge Pump IV; 31-Mixing Tank; 32-Anaerobic Ammonium Oxidation Unit; 33-Intermediate Tank III; 34-AO-MBR Enhanced Denitrification Unit; 35-Effluent Tank; 321-Influent Pump V; 322-Anaerobic Ammonium Oxidation Tank; 323-Residue Sludge Pump V; 331 - Wastewater return pump; 341 - Inlet pump VI; 342 - AO - MBR enhanced denitrification tank; 343 - Agitator III; 344 - Blower IV; 345 - Aerator IV; 346 - MBR membrane unit; 347 - Sludge return pump IV; 348 - Permeate pump; 349 - Waste sludge pump VI; 41 - Mechanical thickening room; 42 - Sludge transfer pump; 43 - Sludge hydrolysis tank; 44 - Sludge hydrolysate dosing pump; 45 - NaOH dosing system; 46 - Supernatant return pump. Detailed implementation method:

[0030] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0031] A certain amount of domestic sewage has a flow rate of 1000L / d and the following properties: pH 6.5-7.5, COD 300-400mg / L, BOD5 150-200mg / L, NH4+ + -N 40-50mg / L, TN 50-65mg / L, SS 200-300mg / L, TP 6-8mg / L. A landfill leachate volume of 60L / d has the following properties: pH 7.5-8.5, COD 5000-6000mg / L, BOD5 2400-3000mg / L, NH4+ + -N 1000-1200mg / L, TN 1200-1500mg / L, SS 500-600mg / L, TP 10-15mg / L. Use Figure 1 The landfill leachate and domestic sewage combined treatment device shown is used for treatment. The device includes a domestic sewage treatment system (1), a landfill leachate treatment system (2), a combined treatment system (3), and a sludge treatment system (4) that are interconnected.

[0032] The domestic sewage treatment system (1) includes an interconnected domestic sewage storage tank (11) and an AO biological phosphorus and carbon removal unit I (12). The AO biological phosphorus and carbon removal unit I (12) is equipped with an influent pump I (121), an AO biological phosphorus and carbon removal tank I (122), a secondary sedimentation tank I (123), a mixer I (124), a blower I (125), an aerator I (126), a sludge return pump I (127), and a waste sludge pump I (128).

[0033] The landfill leachate treatment system (2) includes interconnected landfill leachate storage tank (21), UASB treatment unit (22), intermediate tank I (23), AO biological phosphorus and carbon removal unit II (24), intermediate tank II (25), and short-cut nitrification unit (26). The UASB treatment unit (22) is equipped with influent pump II (221), UASB tank (222), and waste sludge pump II (223). The AO biological phosphorus and carbon removal unit II (24) is equipped with influent pump III (241), AO biological phosphorus and carbon removal tank II (242), secondary sedimentation tank II (243), agitator II (244), blower II (245), aerator II (246), sludge return pump II (247), and waste sludge pump III (248). The short-cut nitrification unit (26) is equipped with an influent pump IV (261), a short-cut nitrification tank (262), a secondary sedimentation tank III (263), a blower III (264), an aeration head III (265), a sludge return pump III (266), and a waste sludge pump IV (267).

[0034] The combined treatment system (3) includes an interconnected mixing tank (31), an anaerobic ammonia oxidation unit (32), an intermediate tank III (33), an AO-MBR enhanced denitrification unit (34), and an effluent tank (35). The anaerobic ammonia oxidation unit (32) is equipped with an influent pump V (321), an anaerobic ammonia oxidation tank (322), and a waste sludge pump V (323). The intermediate tank III (33) is equipped with a wastewater return pump (331). The AO-MBR enhanced denitrification unit (34) is equipped with an influent pump VI (341), an AO-MBR enhanced denitrification tank (342), a mixer III (343), a blower IV (344), an aerator IV (345), an MBR membrane unit (346), a sludge return pump IV (347), a permeate pump (348), and a waste sludge pump VI (349).

[0035] The sludge treatment system (4) includes a sludge mechanical thickening room (41), a sludge transfer pump (42), a sludge hydrolysis tank (43), a sludge hydrolysate addition pump (44), a NaOH addition system (45), and a supernatant return pump (46).

[0036] The domestic sewage storage tank (11) is connected to the inlet of the AO biological phosphorus removal and decarbonization tank I (122) via the inlet pump I (121). The outlet of the AO biological phosphorus removal and decarbonization tank I (122) is connected to the inlet of the secondary sedimentation tank I (123). The anaerobic section of the AO biological phosphorus removal and decarbonization tank I (122) is equipped with a stirrer I (124), and the aerobic section of the AO biological phosphorus removal and decarbonization tank I (122) is equipped with an aerator I (126). The sludge outlet of the secondary sedimentation tank I (123) is connected to the anaerobic section of the AO biological phosphorus removal and decarbonization tank I (122) via the sludge return pump I (127). At the same time, the sludge outlet of the secondary sedimentation tank I (123) is connected to the sludge mechanical thickening room (41) in the sludge treatment system (4) via the excess sludge pump I (128). The outlet of the secondary sedimentation tank I (123) is connected to the mixing tank (31) in the combined treatment system (3).

[0037] The landfill leachate storage tank (21) is connected to the UASB tank (222) via inlet pump II (221), and the outlet of the UASB tank (222) is connected to the intermediate tank I (23); the intermediate tank I (23) is connected to the inlet of the AO biological phosphorus and carbon removal tank II (242) via inlet pump III (241), and the outlet of the AO biological phosphorus and carbon removal tank II (242) is connected to the inlet of the secondary sedimentation tank II (243). In the anaerobic section of 42), a stirrer II (244) is installed. In the aerobic section of AO biological phosphorus removal and decarbonization tank II (242), an aerator II (246) is installed. The aerator II (246) is connected to the blower II (245). The sludge outlet of the secondary sedimentation tank II (243) is connected to the anaerobic section of AO biological phosphorus removal and decarbonization tank II (242) through the sludge return pump II (247). The outlet of the secondary sedimentation tank II (243) is connected to the intermediate tank II (25). Intermediate tank II (25) is connected to the inlet of short-cut nitrification tank (262) via inlet pump IV (261). The outlet of short-cut nitrification tank (262) is connected to the inlet of secondary sedimentation tank III (263). Aerator III (265) is installed in short-cut nitrification tank (262). Aerator III (265) is connected to blower III (264). The sludge outlet of secondary sedimentation tank III (263) is connected to short-cut nitrification tank (262) via sludge return pump III (266). The outlet of secondary sedimentation tank III (263) is connected to mixing tank (31) in combined treatment system (3). The sludge outlets of the UASB tank (222), the secondary sedimentation tank II (243), and the secondary sedimentation tank III (263) are respectively connected to the sludge mechanical thickening room (41) in the sludge treatment system (4) via the residual sludge pumps II (223), III (248), and IV (267).

[0038] The mixing tank (31) is connected to the inlet of the anaerobic ammonia oxidation tank (322) via the inlet pump V (321), and the outlet of the anaerobic ammonia oxidation tank (322) is connected to the intermediate tank III (33). The intermediate tank III (33) is connected to the intermediate tank II (25) via the sewage return pump (331). Intermediate tank III (33) is connected to the inlet of AO-MBR enhanced denitrification tank (342) via inlet pump VI (341). An agitator III (343) is installed in the anoxic section of AO-MBR enhanced denitrification tank (342). An aerator IV (345) is installed in the aerobic section of AO-MBR enhanced denitrification tank (342), and a blower IV (344) is connected to a blower IV (344). An MBR membrane unit (346) is installed in the aerobic section of AO-MBR enhanced denitrification tank (342), and the MBR membrane unit (346) is connected to the effluent tank (35) via a permeate pump (348). The aerobic section of AO-MBR enhanced denitrification tank (342) is connected to the anoxic tank of AO-MBR enhanced denitrification tank (342) via a sludge return pump IV (347). The sludge outlet of the anaerobic ammonia oxidation tank (322) and the sludge outlet of the AO-MBR enhanced denitrification tank (342) are respectively connected to the sludge mechanical thickening room (41) in the sludge treatment system (4) through the excess sludge pump V (323) and the excess sludge pump VI (349).

[0039] The sludge mechanical thickening room (41) is connected to the sludge outlet of the secondary sedimentation tank (123), UASB tank (222), secondary sedimentation tank II (243), secondary sedimentation tank III (263), anaerobic ammonia oxidation tank (322), and AO-MBR enhanced denitrification tank (342) via the waste sludge pumps I (128), II (223), III (248), IV (267), V (323), and VI (349). The sludge mechanical thickening room (41) is connected to the sludge hydrolysis tank (43) via the sludge transfer pump (42). The sludge hydrolysis tank (43) is connected to the anoxic section of the AO-MBR enhanced denitrification tank (342) via the sludge hydrolysate addition pump (44). The NaOH addition system (45) is connected to the sludge hydrolysis tank (43). The sludge mechanical thickening room (41) returns the supernatant of the sludge thickening room to the intermediate tank III (33) via the supernatant return pump (46).

[0040] The above-mentioned device is used for the combined treatment of landfill leachate and domestic sewage. The specific treatment process is as follows:

[0041] 1. System startup

[0042] (1) Start-up of domestic sewage treatment system

[0043] Activated sludge from a municipal wastewater treatment plant was inoculated into the AO biological phosphorus and carbon removal tank I at a concentration of 3500 mg / L. After aeration for 2-3 days, domestic sewage was introduced. The sludge load was set at 0.2-0.3 kg BOD5 / (kg MLSS.d), dissolved oxygen was controlled at 2-3 mg / L, sludge return ratio was 100%, and sludge age was 5-7 days. Under the current sludge load, the COD removal rate reached 80%, the TP removal rate reached 70%, and the ammonia nitrogen oxidation rate was 2%. The system operated stably for 7 days, and the system startup was successful.

[0044] (2) Start-up of landfill leachate treatment system

[0045] 1) Start-up of the UASB treatment unit: Inoculate granular sludge into the UASB tank at a rate of 15 kg VSS / m³. 3 By gradually increasing the leachate flow rate, the volumetric loading rate is set at 3, 5, and 8 kg COD / m³. 3 The COD removal rate will be gradually increased until it reaches over 60% at the current volumetric loading level, then increased to the next sludge loading gradient until it reaches 8 kg COD / m³. 3 .d, UASB processing unit started successfully.

[0046] 2) Start-up of AO biological phosphorus and carbon removal unit II: Inoculate activated sludge from the municipal wastewater treatment plant into AO biological phosphorus and carbon removal tank II. The activated sludge concentration is 3500 mg / L. After entering the UASB unit effluent, allow it to aerate for 2-3 days, then start continuous influent. Gradually increase the sludge load in three gradients: 0.2, 0.4, and 0.6 kg BOD5 / (kg MLSS.d). Control dissolved oxygen at 2-3 mg / L, sludge return ratio at 100%, sludge age at 4-5 days. Under the current sludge load, the COD removal rate reaches over 60%, the TP removal rate reaches over 50%, and the system operates stably for over 7 days. Increase to the next sludge load gradient until the sludge load reaches 0.6 kg BOD5 / (kg MLSS.d). Under this sludge load, the COD removal rate reaches over 60%, the TP removal rate reaches over 50%, and the ammonia nitrogen oxidation rate is less than 5%, and the system operates stably for over 7 days. The system start-up is successful.

[0047] 3) Start-up of the short-cut nitrification unit: Inoculate the municipal wastewater treatment plant's activated sludge into the short-cut nitrification tank. The activated sludge concentration is 3500 mg / L. After aeration for 2-3 days, start feeding the effluent from the AO biological phosphorus and carbon removal unit II. Control the total nitrogen load at 0.04-0.05 kgTN / (kgMLSS.d), dissolved oxygen at 1.5-3 mg / L, sludge return ratio at 300-400%, and sludge age at 10-15 days. When the ammonia nitrogen removal rate reaches 80% and the nitrite accumulation rate reaches 85%, and the system has been running stably for more than 7 days, the system is considered successfully started up.

[0048] (3) Start-up of the combined processing system

[0049] 1) Start-up of the anaerobic ammonia oxidation unit: Inoculate the packing material with a relative abundance of anaerobic ammonia oxidizing bacteria greater than 10%, with a packing material filling ratio of 20-30%. First, start-up is performed using nitrogen-containing wastewater prepared with tap water. The wastewater concentration is 60 mg / L for ammonia nitrogen and 80 mg / L for nitrite nitrogen, with a hydraulic retention time of 12-15 hours. When the total nitrogen (TN) removal rate reaches over 80% and is maintained for over 7 days, proceed to the next stage. The prepared water and water from the mixing tank are mixed sequentially at volume ratios of 2:1, 1:1, 1:2, and 0:1 to prepare the influent for system startup. The system hydraulic retention time is 12 hours. When the TN removal rate reaches over 70% and operates stably for 7 days, gradually increase the proportion of water from the mixing tank in the influent until the influent is entirely from the mixing tank, indicating successful system startup.

[0050] 2) Start-up of the AO-MBR enhanced denitrification unit: Inoculate the AO-MBR enhanced denitrification tank with activated sludge from the municipal wastewater treatment plant at a concentration of 6000 mg / L. After adding effluent from the anaerobic ammonia oxidation unit and allowing it to aerate for 2-3 days, start feeding water. Gradually increase the sludge load according to four gradients: 0.01, 0.02, 0.03, and 0.04 kgTN / (kgMLSS.d). Control the dissolved oxygen at 2-3 mg / L and the internal recirculation ratio at 50-100%. Once the ammonia nitrogen removal rate reaches over 80% under the current sludge load and remains stable for over 7 days, increase to the next sludge load gradient until the sludge load reaches 0.04 kgTN / kg(MLSS.d). The unit is then successfully started up.

[0051] (4) Start-up of sludge treatment system

[0052] The remaining sludge from the entire system is concentrated in the sludge mechanical thickening chamber and then injected into the sludge hydrolysis tank by the sludge transfer pump until it is full. The concentration of the concentrated sludge is 12000 mg / L. NaOH is added to the sludge hydrolysis tank by the NaOH dosing system to control the fermentation pH value at 10±0.5. The sludge is fermented in a closed system for 6 days. Then, 1 / 6 of the fermented sludge volume of the sludge hydrolysis tank is discharged daily, and the same volume of concentrated sludge is introduced at the same time. The NaOH dosing system controls the pH value of the sludge hydrolysis tank at 10±0.5. When the acid production of the sludge reaches 200-300 mg (COD) / g (VSS) and stabilizes for 10 days, the system is considered to have started up successfully.

[0053] 2. System Operation

[0054] After each system is successfully started, it is connected in series to begin operation. Domestic sewage enters the anaerobic section of the AO biological phosphorus and carbon removal tank I via influent pump I from the sewage storage tank. Under the action of stirrer I, it mixes with activated sludge returned from the secondary settling tank I. Polyphosphate-accumulating bacteria in the activated sludge absorb organic matter and release phosphorus. The sludge mixture then enters the aerobic section to complete the phosphorus uptake reaction and remove organic matter. Simultaneously, by controlling the sludge load at 0.2-0.3 kg BOD5 / (kg MLSS.d) and the sludge age at 5-7 days, the growth of nitrifying bacteria is inhibited, and the ammonia nitrogen oxidation rate is around 2%. The mixed liquor treated in the aerobic section enters the secondary settling tank I for sedimentation for 2-3 hours. The ammonia nitrogen-containing supernatant then enters the mixing tank. The sludge return ratio in the secondary settling tank I is controlled at 50-100%. The excess sludge is discharged to the mechanical sludge thickening room by the waste sludge pump I. After treatment by the domestic sewage treatment system, the effluent quality is as follows: COD 60-80 mg / L, BOD5 15-20 mg / L, NH4+ + -N 39.2-49mg / L, TN48-62mg / L, SS20-30mg / L, TP0.6-0.8mg / L.

[0055] Landfill leachate enters the UASB tank from the leachate storage tank via influent pump II. The influent flow rate is controlled to maintain the UASB volumetric loading rate at 8 kg COD / m³. 3 After the removal of easily degradable organic matter from the landfill leachate in the UASB tank, the effluent quality of the UASB tank is COD 2000-2400 mg / L, BOD5 240-300 mg / L, and NH4+. + -N 1150-1350mg / L, TN 1200-1500mg / L, SS 200-240mg / L, TP 10-15mg / L. The effluent enters intermediate tank I, and the water in intermediate tank I is pumped by inlet pump III into the anaerobic section of AO biological phosphorus and carbon removal tank II. Under the action of stirrer II, it mixes with the activated sludge returned from secondary sedimentation tank II. The activated sludge absorbs organic matter and releases phosphorus. Then, the sludge mixture enters the aerobic section to complete the phosphorus absorption reaction and remove organic matter. During operation, the sludge load is controlled at 0.5-0.6kgBOD5 / (kgMLSS.d), the sludge age is 4-5 days, the growth of nitrifying bacteria is inhibited, and the ammonia nitrogen oxidation rate is controlled below 5%. After the aerobic section mixture enters secondary sedimentation tank II for 2-3 hours of sedimentation, the effluent quality of the AO biological phosphorus and carbon removal tank is COD 1200-1440mg / L, BOD5 24-30mg / L, NH4+ +-N 1095-1280mg / L, TN 1200-1500mg / L, SS 80-96mg / L, TP 1-1.5mg / L. The effluent from the AO biological phosphorus and carbon removal tank enters intermediate tank II, and the sludge return ratio in the secondary sedimentation tank is controlled at 50-100%. The effluent from the anaerobic ammonia oxidation tank and the effluent from the AO biological phosphorus and carbon removal tank II in the landfill leachate treatment system are mixed in intermediate tank II at a mixing ratio of 3:1. The ammonia nitrogen concentration in intermediate tank II is controlled at 300-400 mg / L. The wastewater from intermediate tank II enters the short-cut nitrification tank via influent pump IV. The total nitrogen load in the short-cut nitrification tank is controlled at 0.04-0.05 kgTN / (kgMLSS.d), dissolved oxygen at 1.5-3 mg / L, sludge return ratio at 100-200%, and sludge age at 10-15 days. After the ammonia nitrogen in the leachate is converted to nitrite in the short-cut nitrification tank, it enters the secondary sedimentation tank III for 2-3 hours of sedimentation. The effluent quality from the short-cut nitrification tank is COD 390-480 mg / L, BOD5 7-9 mg / L, and NH4+. + -N 8-10mg / L, NO2 - -N 260-300mg / L, NO3 - -N 45-50mg / L, TN 310-390mg / L, SS 10-15mg / L, TP 0.7-1mg / L, effluent enters the mixing tank. Residual sludge from the UASB tank, secondary settling tank II, and secondary settling tank III enters the sludge mechanical thickening room via residual sludge pumps II, III, and IV, respectively.

[0056] The effluent from the domestic sewage treatment system and the leachate treatment system are mixed in a mixing tank. The mixed water quality is: COD 124-157 mg / L, BOD5 13-18 mg / L, NH4+... + -N33-41mg / L, NO2 - -N 50-58mg / L, NO3 - -N 10-12 mg / L, TN 100-125 mg / L, SS 18-27 mg / L, TP 0.6-0.8 mg / L. Water from the mixing tank enters the anaerobic ammonia oxidation tank via influent pump V. The influent flow rate is adjusted to make the volumetric loading rate of the anaerobic ammonia oxidation tank 0.2-0.3 kgTN / (m³). 3 .d) Anaerobic ammonia-oxidizing bacteria utilize ammonia nitrogen and nitrite nitrogen in the mixed tank water for anaerobic ammonia oxidation to remove nitrogen. The effluent quality of the anaerobic ammonia oxidation tank is COD 115-140 mg / L, BOD5 10-15 mg / L, and NH4+. + -N 3-4mg / L, NO2 - -N 2-3mg / L, NO3 --N 12-15 mg / L, TN 24-36 mg / L, SS 15-20 mg / L, TP 0.6-0.8 mg / L, the effluent enters intermediate tank III. Simultaneously, the supernatant from the sludge mechanical thickening room is also returned to intermediate tank III. Due to insufficient anaerobic ammonia oxidation, an imbalance in the ratio of ammonia nitrogen to nitrite nitrogen, and the return of supernatant from the sludge mechanical thickening room, ammonia nitrogen, nitrite nitrogen, and nitrite nitrogen may be present in the wastewater in intermediate tank III. Part of the wastewater in intermediate tank III enters intermediate tank II via a wastewater return pump, and part enters the anoxic section of the AO-MBR enhanced denitrification tank via influent pump IV. Under the action of agitator III, the activated sludge utilizes nitrate and nitrite nitrogen from the intermediate tank and internal reflux mixed liquor, as well as carbon sources from the sludge hydrolysate added by the sludge hydrolysate dosing pump, for denitrification. The mixed liquor then enters the aerobic section for further removal of ammonia nitrogen and organic matter. Finally, after filtration by the MBR membrane unit, it enters the effluent tank for discharge. The final effluent quality is COD 60-70 mg / L, BOD5 5-10 mg / L, and NH4+. + -N 1-2mg / L, NO3 - -N 5-7 mg / L, TN 10-15 mg / L, SS 5-10 mg / L, TP 0.5-0.7 mg / L. During operation, the activated sludge concentration in the AO-MBR enhanced denitrification tank is 5000-6000 mg / L, the sludge nitrogen load is controlled at 0.03-0.04 kgTN / (kgMLSS.d), the HRT in the anoxic zone is 2-3 h, the HRT in the aerobic zone is 4-6 h, the sludge age is 20-25 days, the dissolved oxygen is controlled at 2-3 mg / L, the sludge return ratio is 100-150%, and the MBR membrane flux is 40-50 L / m³. 2 The excess sludge from the anaerobic ammonia oxidation tank and the AO-MBR enhanced denitrification tank is discharged to the sludge mechanical thickening room via excess sludge pump V and excess sludge pump VI, respectively.

[0057] The excess sludge discharged from the domestic sewage treatment system, landfill leachate treatment system, and combined treatment system enters the sludge mechanical thickening room for thickening. The supernatant in the thickening room is returned to the intermediate water tank III by the supernatant return pump. The sludge hydrolysis liquid addition pump continuously draws hydrolyzed sludge from the sludge hydrolysis tank every day and sends it to the anoxic section of the AO-MBR enhanced denitrification tank. By controlling the amount of fermented sludge added, the BOD5 / TN ratio of the anoxic section of the AO-MBR enhanced denitrification tank is controlled to be 4-5. The daily volume drawn is 1 / 6 of the volume of the sludge hydrolysis tank. Then, the same volume of thickened excess sludge is sent to the sludge hydrolysis tank in one go by the sludge transfer pump. The sludge retention time is 6 days. At the same time, the NaOH addition system adds NaOH to the sludge fermentation tank to control the pH value of the entire fermentation process at 10±0.5.

Claims

1. An apparatus for the combined treatment of landfill leachate and domestic sewage, characterized in that: It includes an interconnected domestic sewage treatment system (1), a landfill leachate treatment system (2), a combined treatment system (3), and a sludge treatment system (4); The domestic sewage treatment system (1) includes an interconnected domestic sewage storage tank (11) and an AO biological phosphorus removal and decarbonization unit I (12). The AO biological phosphorus removal and decarbonization unit I (12) is equipped with an influent pump I (121), an AO biological phosphorus removal and decarbonization tank I (122), a secondary sedimentation tank I (123), a mixer I (124), a blower I (125), an aerator I (126), a sludge return pump I (127), and a waste sludge pump I (128). The landfill leachate treatment system (2) includes interconnected landfill leachate storage tank (21), UASB treatment unit (22), intermediate tank I (23), AO biological phosphorus and carbon removal unit II (24), intermediate tank II (25), and short-cut nitrification unit (26); the UASB treatment unit (22) is equipped with influent pump II (221), UASB tank (222), and excess sludge pump II (223); the AO biological phosphorus and carbon removal unit II (24) is equipped with influent pump III (241), AO biological phosphorus removal unit II (243), and AO biological phosphorus removal unit II (244). Carbon removal tank II (242), secondary sedimentation tank II (243), agitator II (244), blower II (245), aerator II (246), sludge return pump II (247), and waste sludge pump III (248); the short-cut nitrification unit (26) is equipped with influent pump IV (261), short-cut nitrification tank (262), secondary sedimentation tank III (263), blower III (264), aerator III (265), sludge return pump III (266), and waste sludge pump IV (267); The combined treatment system (3) includes an interconnected mixing tank (31), an anaerobic ammonia oxidation unit (32), an intermediate tank III (33), an AO-MBR enhanced denitrification unit (34), and an effluent tank (35); the anaerobic ammonia oxidation unit (32) is equipped with an influent pump V (321), an anaerobic ammonia oxidation tank (322), and a waste sludge pump V (323); the intermediate tank III (33) is equipped with a wastewater return pump (331); the AO-MBR enhanced denitrification unit (34) is equipped with an influent pump VI (341), an AO-MBR enhanced denitrification tank (342), a mixer III (343), a blower IV (344), an aerator IV (345), an MBR membrane unit (346), a sludge return pump IV (347), a permeate pump (348), and a waste sludge pump VI (349); The sludge treatment system (4) includes a sludge mechanical thickening room (41), a sludge transfer pump (42), a sludge hydrolysis tank (43), a sludge hydrolysate addition pump (44), a NaOH addition system (45), and a supernatant return pump (46). The domestic sewage storage tank (11) is connected to the inlet of the AO biological phosphorus and carbon removal tank I (122) via the inlet pump I (121). The outlet of the AO biological phosphorus and carbon removal tank I (122) is connected to the inlet of the secondary sedimentation tank I (123). A stirrer I (124) is installed in the anaerobic section at the front of the AO biological phosphorus and carbon removal tank I (122), and an aerator I (126) is installed in the aerobic section at the rear of the AO biological phosphorus and carbon removal tank I (122). Connected to blower I (125), the sludge outlet of secondary sedimentation tank I (123) is connected to the anaerobic section in front of AO biological phosphorus and carbon removal tank I (122) via sludge return pump I (127). At the same time, the sludge outlet of secondary sedimentation tank I (123) is connected to the sludge mechanical thickening room (41) in sludge treatment system (4) via excess sludge pump I (128). The outlet of secondary sedimentation tank I (123) is connected to the mixing tank (31) in combined treatment system (3). The landfill leachate storage tank (21) is connected to the UASB tank (222) via inlet pump II (221), and the outlet of the UASB tank (222) is connected to the intermediate tank I (23). The intermediate tank I (23) is connected to the inlet of the AO biological phosphorus and carbon removal tank II (242) via inlet pump III (241), and the outlet of the AO biological phosphorus and carbon removal tank II (242) is connected to the inlet of the secondary sedimentation tank II (243). The anaerobic section at the front is equipped with a stirrer II (244), and the aerobic section at the rear of the AO biological phosphorus and carbon removal tank II (242) is equipped with an aerator II (246). The aerator II (246) is connected to the blower II (245). The sludge outlet of the secondary sedimentation tank II (243) is connected to the anaerobic section of the AO biological phosphorus and carbon removal tank II (242) through a sludge return pump II (247). The outlet of the secondary sedimentation tank II (243) is connected to the intermediate tank II (25). Tank II (25) is connected to the inlet of the short-cut nitrification tank (262) via inlet pump IV (261). The outlet of the short-cut nitrification tank (262) is connected to the inlet of the secondary sedimentation tank III (263). An aeration head III (265) is installed in the short-cut nitrification tank (262), and the aeration head III (265) is connected to the blower III (264). The sludge outlet of the secondary sedimentation tank III (263) is connected to the short-cut nitrification tank (262) via sludge return pump III (266). The outlet of the secondary sedimentation tank III (263) is connected to the mixing tank (31) in the combined treatment system (3); the sludge outlet of the UASB tank (222), the sludge outlet of the secondary sedimentation tank II (243), and the sludge outlet of the secondary sedimentation tank III (263) are respectively connected to the sludge mechanical thickening room (41) in the sludge treatment system (4) through the excess sludge pump II (223), the excess sludge pump III (248), and the excess sludge pump IV (267); The mixing tank (31) is connected to the inlet of the anaerobic ammonia oxidation tank (322) via the inlet pump V (321). The outlet of the anaerobic ammonia oxidation tank (322) is connected to the intermediate tank III (33). The intermediate tank III (33) is connected to the intermediate tank II (25) via the wastewater return pump (331). The intermediate tank III (33) is connected to the inlet of the AO-MBR enhanced denitrification tank (342) via the inlet pump VI (341). The anoxic section at the front of the AO-MBR enhanced denitrification tank (342) is equipped with a stirrer III (343). The aerobic section at the rear of the AO-MBR enhanced denitrification tank (342) is equipped with an aerator IV (345). The aerator IV (345) is connected to the blower IV. (344) Connecting, an MBR membrane unit (346) is installed in the aerobic section of the AO-MBR enhanced denitrification tank (342). The MBR membrane unit (346) is connected to the effluent tank (35) through a product water pump (348). The aerobic section in the AO-MBR enhanced denitrification tank (342) is connected to the anoxic section in the AO-MBR enhanced denitrification tank (342) through a sludge return pump IV (347). The sludge outlet end of the anaerobic ammonia oxidation tank (322) and the sludge outlet end of the AO-MBR enhanced denitrification tank (342) are respectively connected to the sludge mechanical thickening room (41) in the sludge treatment system (4) through a waste sludge pump V (323) and a waste sludge pump VI (349). The sludge mechanical thickening room (41) is connected to the secondary sedimentation tank (123), UASB tank (222), secondary sedimentation tank II (248), secondary sedimentation tank III (267), anaerobic ammonia oxidation tank (322), and AO-MBR enhanced denitrification tank (349) via waste sludge pumps I (128), II (223), III (243), IV (267), V (323), and VI (349), respectively. 2) Sludge outlet connection; The sludge mechanical thickening room (41) is connected to the sludge hydrolysis tank (43) through the sludge transfer pump (42), the sludge hydrolysis tank (43) is connected to the anoxic section of the AO-MBR enhanced denitrification tank (342) through the sludge hydrolysis liquid addition pump (44), the NaOH addition system (45) is connected to the sludge hydrolysis tank (43), and the sludge mechanical thickening room (41) returns the supernatant of the sludge thickening room to the intermediate tank III (33) through the supernatant return pump (46).

2. A method for jointly treating landfill leachate and domestic sewage using the apparatus described in claim 1, characterized in that, Includes the following processes: (1) Start-up and operation of the domestic sewage treatment system: During the start-up period, activated sludge from the municipal sewage treatment plant was inoculated into the AO biological phosphorus and carbon removal tank I (122). The activated sludge concentration was 3000-4000 mg / L. After aeration for 2-3 days, domestic sewage was introduced. The sludge load was 0.2-0.3 kg BOD5 / (kg MLSS.d), dissolved oxygen was controlled at 2-3 mg / L, sludge return ratio was 100%, sludge age was 5-7 days, COD removal rate reached more than 60% under the current sludge load, TP removal rate reached more than 50%, and ammonia nitrogen oxidation rate was less than 5%. The system was stable for more than 7 days, and the system was successfully started up. During operation, domestic sewage was introduced from the domestic sewage storage tank into the AO biological phosphorus and carbon removal tank via influent pump I (121). In the anaerobic section of carbon tank I (122), activated sludge is mixed with activated sludge returned from secondary sedimentation tank I (123) under the action of stirrer I. Polyphosphate-accumulating bacteria in activated sludge absorb organic matter to release phosphorus. Then, the sludge mixture enters the aerobic section to complete the phosphorus absorption reaction and remove organic matter. At the same time, by controlling the sludge load at 0.2-0.3 kg BOD5 / (kg MLSS.d) and the sludge age at 5-7 days, the growth of nitrifying bacteria is inhibited, and the oxidation rate of ammonia nitrogen is controlled within 5%. After the mixture treated in the aerobic section enters the secondary sedimentation tank I (123) for sedimentation for 2-3 hours, the supernatant containing ammonia nitrogen enters the mixing tank (31). The sludge return ratio of secondary sedimentation tank I (123) is controlled at 50-100%, and the excess sludge is discharged to the mechanical sludge thickening room (41) by the excess sludge pump I (128). (2) Start-up and operation of landfill leachate treatment system: 1) Start-up of UASB treatment unit: Inoculate granular sludge into UASB tank (222) at a rate of 10-15 kg VSS / m³. 3 By gradually increasing the leachate flow rate, the volumetric loading rate is set at 3 kg COD / m³. 3 .d、5kgCOD / m 3 .d、8kgCOD / m 3 The COD removal rate is gradually increased. Once the COD removal rate reaches over 60% at the current volumetric load, the rate is increased to the next volumetric load until it reaches 8 kg COD / m³. 3 .d, UASB processing unit started successfully; 2) Start-up of AO biological phosphorus and carbon removal unit II: Activated sludge from the municipal wastewater treatment plant was inoculated into AO biological phosphorus and carbon removal tank II (242). The activated sludge concentration was 3000-4000 mg / L. After adding effluent from the UASB unit, the tank was aerated for 2-3 days, after which continuous influent was started. The sludge loading was gradually increased, with the sludge loading set at 0.2 kg BOD5 / (kg MLSS.d), 0.4 kg BOD5 / (kg MLSS.d), and 0.6 kg BOD5 / (kg MLSS.d). The sludge load is gradually increased in three gradients, with dissolved oxygen controlled at 2-3 mg / L, sludge return ratio at 100%, and sludge age at 4-5 days. When the COD removal rate reaches over 60% and the TP removal rate reaches over 50% under the current sludge load and remains stable for over 7 days, the load is increased to the next sludge load gradient, until the sludge load reaches 0.6 kg BOD5 / (kg MLSS.d). Under this 0.6 kg BOD5 / (kg MLSS.d) sludge load, the COD removal rate reaches over 60% and the TP removal rate reaches over 50%. When the ammonia nitrogen oxidation rate is above 0% and less than 5% and the system has been running stably for more than 7 days, the system is considered to have started successfully; 3) Start-up of the short-cut nitrification unit: Inoculate the activated sludge from the municipal wastewater treatment plant into the short-cut nitrification tank (262), with an activated sludge concentration of 3000-4000 mg / L. After aeration for 2-3 days, start adding the effluent from the AO biological phosphorus and carbon removal unit II. Control the total nitrogen load at 0.04-0.05 kgTN / (kgMLSS.d) and dissolved oxygen at 1.5-3 mg / L by controlling the influent flow rate. 300-400%, sludge age 10-15 days, the system is successfully started when the ammonia nitrogen removal rate reaches 80%, the nitrite accumulation rate reaches 85%, and it has been running stably for more than 7 days; after the UASB treatment unit, AO biological phosphorus and carbon removal unit II and short-cut nitrification unit are all successfully started, the three units are connected in series. The landfill leachate enters the UASB tank (222) from the landfill leachate storage tank (21) through the influent pump II (221). The volumetric loading of the UASB is kept at 6-8 kg COD / m³ by controlling the influent flow rate. 3 After the removal of easily degradable organic matter from the landfill leachate in the UASB, the effluent enters intermediate tank I (23). The water in intermediate tank I (23) is pumped by inlet pump III (241) into the anaerobic section of AO biological phosphorus and carbon removal tank II (242). Under the action of stirrer II, it mixes with the activated sludge returned from secondary sedimentation tank II (243). The activated sludge absorbs organic matter and releases phosphorus. Then, the sludge mixture enters the aerobic section to complete the phosphorus absorption reaction and remove organic matter. During operation, the process is controlled by... The sludge loading rate is 0.5-0.6 kg BOD5 / (kg MLSS.d), the sludge age is 4-5 days, the growth of nitrifying bacteria is inhibited, and the ammonia nitrogen oxidation rate is controlled within 5%. Then, the aerobic mixed liquor enters the secondary sedimentation tank II (243) for sedimentation for 2-3 hours. The ammonia nitrogen-containing supernatant then enters the intermediate tank II (25). The sludge return ratio of the secondary sedimentation tank II (243) is controlled at 50-100%. The effluent from the anaerobic ammonia oxidation tank, i.e., the intermediate tank III (33), is pumped through the sewage return pump (331). In the water and landfill leachate treatment system, the effluent from the AO biological phosphorus and carbon removal tank II is mixed in intermediate tank II (25) at a volume ratio of 3-4:

1. The ammonia nitrogen concentration in intermediate tank II (25) is controlled at 300-400 mg / L. The wastewater in intermediate tank II is pumped into the short-cut nitrification tank (262) by influent pump IV (261). The total nitrogen load in the short-cut nitrification tank (262) is controlled at 0.04-0.05 kgTN / (kgMLSS.d), and the dissolved oxygen is 1.5-3 m³ / kg. g / L, sludge return ratio 100-200%, sludge age 10-15d, after the ammonia nitrogen in the mixed liquor is converted into nitrite nitrogen in the short-cut nitrification tank (262), it enters the secondary sedimentation tank III (263) for sedimentation for 2-3h, and then the supernatant enters the mixing tank (31); the excess sludge from the UASB tank (222), secondary sedimentation tank II (243) and secondary sedimentation tank III (263) enters the sludge mechanical thickening room (41) through excess sludge pump II, excess sludge pump III and excess sludge pump IV respectively. (3) Start-up and operation of the combined treatment system: 1) Start-up of the anaerobic ammonia oxidation unit: Inoculate the packing material with a relative abundance of anaerobic ammonia oxidizing bacteria greater than 10%, and the packing material filling ratio is 20-30%; First, start-up is carried out using nitrogen-containing wastewater prepared with tap water, with ammonia nitrogen concentration of 60 mg / L, nitrite nitrogen concentration of 80 mg / L, and hydraulic retention time of 12-15 h. When the TN removal rate reaches more than 80% and is maintained for more than 7 days, the next stage is entered; The next stage is: to mix the nitrogen-containing wastewater and the water in the mixing tank (31) according to the requirements of the mixing tank (31). The anaerobic ammonia oxidation unit was started by mixing the influent in volume ratios of 2:1, 1:1, 1:2, and 0:

1. The hydraulic retention time of the system was 12 hours. After the TN removal rate reached more than 70% and the system operated stably for 7 days, the proportion of water in the mixing tank in the influent was gradually increased until all the influent was water from the mixing tank, and the system was successfully started. 2) Start-up of the AO-MBR enhanced denitrification unit: Activated sludge from the municipal wastewater treatment plant was inoculated into the AO-MBR enhanced denitrification tank (342) with an activated sludge concentration of 5%. After adding 000-6000 mg / L of anaerobic ammonia oxidation unit effluent and allowing it to aerate for 2-3 days, continuous influent is introduced. The sludge loading is gradually increased according to four sludge loading gradients: 0.01 kg TN / (kg MLSS.d), 0.02 kg TN / (kg MLSS.d), 0.03 kg TN / (kg MLSS.d), and 0.04 kg TN / (kg MLSS.d). Dissolved oxygen is controlled at 2-3 mg / L, and the internal recirculation ratio is 50-100%. Ammonia nitrogen removal under the current sludge loading is achieved. When the sludge loading rate reaches 80% or higher and operates stably for more than 7 days, the sludge loading is increased to the next sludge loading gradient until the sludge loading reaches 0.04 kgTN / kg (MLSS.d), indicating successful unit startup. After the successful startup of the anammox unit and the AO-MBR enhanced denitrification unit, the two units are connected in series. Water in the mixing tank (31) enters the anammox tank (322) via the influent pump V (321). The influent flow rate is adjusted to make the volumetric loading of the anammox tank 0.2-0.3 kgTN / (m³) 3 .d), anaerobic ammonia-oxidizing bacteria utilize ammonia nitrogen and nitrite nitrogen in the water of the mixing tank (31) to carry out anaerobic ammonia oxidation reaction to remove nitrogen, and the effluent enters the intermediate tank III (33); at the same time, the supernatant of the sludge mechanical thickening room (41) is also returned to the intermediate tank III (33); due to insufficient anaerobic ammonia oxidation reaction, or an uncoordinated ratio of ammonia nitrogen and nitrite nitrogen, ammonia nitrogen, nitrite nitrogen and nitrite nitrogen may be present in the wastewater of the intermediate tank III (33); part of the wastewater in the intermediate tank III enters the intermediate tank II (25) through the wastewater return pump (331) to dilute the concentration of ammonia nitrogen in the effluent of the AO biological phosphorus and carbon removal unit II to 300-400 mg / L, and the other part of the intermediate tank III enters the anoxic section of the AO-MBR enhanced denitrification tank through the influent pump VI (341); under the action of the stirrer III, the activated sludge utilizes The nitrate and nitrite nitrogen in the sludge returned by intermediate tank III (33) and internal reflux mixed liquor, i.e., sludge return pump IV (347), and the carbon source in the sludge hydrolysate added by sludge hydrolysate addition pump (44) are denitrified. Then the mixed liquor enters the aerobic section for further removal of ammonia nitrogen and organic matter, and is finally filtered by the MBR membrane unit and discharged into the effluent tank. During operation, the activated sludge concentration in the AO-MBR enhanced denitrification tank (342) is 5000-6000 mg / L, the sludge nitrogen load is controlled at 0.03-0.04 kgTN / (kgMLSS.d), the HRT in the anoxic section is 2-3 h, the HRT in the aerobic section is 4-6 h, the sludge age is 20-25 d, the dissolved oxygen is controlled at 2-3 mg / L, the sludge return ratio is 100-150%, and the MBR membrane flux is 40-50 L / m 2 The excess sludge from the anaerobic ammonia oxidation tank (322) and the AO-MBR enhanced denitrification tank (342) is discharged to the sludge mechanical thickening room via excess sludge pump V (323) and excess sludge pump VI (349), respectively. (4) Start-up and operation of the sludge treatment system: Start-up of the sludge hydrolysis tank: After the remaining sludge of the entire system is concentrated in the sludge mechanical thickening room (41), it is injected into the sludge hydrolysis tank (43) by the sludge transfer pump (42) until it is full. The concentration of the concentrated sludge in the sludge hydrolysis tank (43) is 10000-15000 mg / L. NaOH is added to the sludge hydrolysis tank by the NaOH dosing system to control the fermentation pH value at 10±0.

5. The sludge is fermented in a closed system for 6-8 days. Then, 1 / 8 to 1 / 6 of the fermented sludge volume of the sludge hydrolysis tank is discharged every day, and the same volume of concentrated sludge is introduced at the same time. The NaOH dosing system controls the pH value of the sludge hydrolysis tank at 10±0.

5. When the acid production of the sludge reaches 200-300 mg (COD) / g (VSS) and stabilizes for 10 days, the system is put into operation. The system was successfully started. After successful start-up, the excess sludge discharged from the domestic sewage treatment system, landfill leachate treatment system and combined treatment system entered the sludge mechanical thickening room for thickening. The supernatant in the mechanical thickening room (41) was returned to the intermediate tank III (33) by the supernatant return pump (46). The sludge hydrolysis liquid addition pump continuously pumped hydrolyzed sludge from the sludge hydrolysis tank (43) every day and sent it to the anoxic section of the AO-MBR enhanced denitrification tank (342). The volume pumped every day was 1 / 8 to 1 / 6 of the volume of the sludge hydrolysis tank. Then, the same volume of thickened excess sludge was sent to the sludge hydrolysis tank (43) once by the sludge transfer pump (42). The sludge retention time was 6-8 days. At the same time, the NaOH addition system added NaOH to the sludge fermentation tank to control the pH value of the entire fermentation process at 10±0.

5.

3. The method according to claim 2, characterized in that, The operation of the domestic sewage treatment system, the landfill leachate treatment system, the combined treatment system, and the sludge treatment system can occur simultaneously. That is, the materials used in the operation of any one of these four systems are the same materials used in the operation of the other three systems.

Images