Sludge filtrate and kitchen liquid co-fermentation treatment system and treatment method

Abstract

The invention discloses a sludge filtrate and kitchen liquid co-fermentation treatment system and a treatment method. The treatment system comprises a material mixing tank, an anaerobic digestion tank, a cyclone separator, a solid-liquid separation tank, a sewage storage tank, a nitrosation reaction tank and an anaerobic ammonia oxidation reaction tank which are sequentially connected, the material mixing tank is used for uniformly mixing sludge filtrate and kitchen liquid, the anaerobic digestion tank is used for carrying out anaerobic digestion reaction on the sludge filtrate and the kitchen liquid to generate biogas, the cyclone separator and the solid-liquid separation tank are used for carrying out secondary solid-liquid separation on fermentation materials, and sewage obtained by separation enters the sewage storage tank to be cached; one part of sewage in the sewage storage tank sequentially enters the nitrosation reaction tank and the anaerobic ammonia oxidation reaction tank to be purified, and the other part of sewage enters the waste heat recoverer to exchange heat with a mixed material in the material mixing tank. The device has the characteristics of compact structure, high operation stability, high treatment efficiency and the like, realizes treatment of wastes with wastes, and improves the co-fermentation efficiency and the operation economy.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and relates to a sludge filtrate and kitchen waste co-fermentation treatment system and treatment method, in particular to the co-anaerobic fermentation of high-pH sludge filtrate produced by alkaline conditioning and dehydration of municipal sludge and kitchen waste after three-phase separation, without the need for acidification and neutralization treatment of the sludge filtrate, and can improve the co-fermentation efficiency and operation economy, so as to achieve waste treatment with waste, and the wastewater after fermentation is combined with anaerobic ammonia oxidation process treatment to improve environmental protection and energy saving. Background Art

[0002] Sludge dehydration is an important part of sludge terminal disposal. In terms of sludge and garbage co-combustion, cement kiln co-combustion, sludge separate incineration, resource utilization, etc., it is necessary to first reduce the sludge moisture content. Sludge alkaline conditioning can effectively destroy cell walls and cause saponification reaction. After mechanical dehydration, the sludge moisture content can generally be lower than 50%. It has many advantages such as low cost, high efficiency, low moisture content, and killing of bacteria. Compared with traditional sludge coagulation / flocculation dehydration, the reduction effect is more obvious, and compared with sludge thermal drying technology, it has energy-saving advantages. Due to the use of alkaline agents such as NaOH, Ca (OH) 2, MgO, etc., the pH value of the sludge dehydration filtrate is 11-12, the total nitrogen is 2000-3000 mg / L, and the C / N ratio is 5-10. The wastewater needs to be treated before it can enter the sewage network or be recycled. Generally speaking, the anaerobic fermentation process is suitable for a C / N ratio between 20 and 30, and the AO process is suitable for a C / N ratio between 4 and 5. The C / N ratio of the wastewater is quite different from that of the two processes, which will lead to low biodegradability of anaerobic fermentation treatment, low unit gas production and low economic efficiency, and excessive carbon source in the AO process is unfavorable to aerobic bacteria and waste of carbon resources. At the same time, acid needs to be added to adjust the pH, which has problems such as large acid consumption, high cost, and chemical corrosion.

[0003] Kitchen waste has a high organic content, contains oil, many impurities and high salt. It usually needs to undergo coarse / fine multi-stage sorting to remove large-particle debris, and then undergo high-temperature steaming and three-phase separation to separate the upper layer of oil and the bottom layer of residue. The remaining aqueous phase has a pH value of about 3 to 4, which is weakly acidic, and contains a large amount of organic acids and VFAs, which can be rapidly degraded organic matter and some oil. The COD is between 80,000 and 100,000 mg / L, and the VSS is greater than 80%. Acidification, scum foam and salt accumulation are easily produced during anaerobic fermentation, affecting stable operation. Summary of the invention

[0004] The technical problem to be solved by the present invention is to solve the above-mentioned problems in the prior art and to provide a sludge filtrate and kitchen liquid co-fermentation treatment system and treatment method which is simple in principle, convenient in operation and conducive to improving treatment efficiency.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A sludge filtrate and kitchen liquid co-fermentation treatment system comprises a material mixing tank, an anaerobic digestion tank, a cyclone separator, a solid-liquid separation tank, a sewage storage tank, a nitrification reaction tank and an anaerobic ammonium oxidation reaction tank which are sequentially connected through pipelines; the material mixing tank is used to achieve uniform mixing of high-pH sludge filtrate generated by alkaline conditioning and dehydration of municipal sludge and kitchen liquid after three-phase separation of kitchen waste; the anaerobic digestion tank is used to achieve anaerobic digestion reaction of the sludge filtrate and the kitchen liquid to generate biogas; the cyclone separator and the solid-liquid separation tank are used to achieve secondary solid-liquid separation of fermented materials generated in the anaerobic digestion tank; the separated sewage enters a sewage storage tank for buffering; a part of the sewage in the sewage storage tank enters a nitrification reaction tank and an anaerobic ammonium oxidation reaction tank in sequence for purification treatment; the obtained tail water is discharged into the municipal sewage pipe network after meeting the standards; another part of the sewage in the sewage storage tank enters a waste heat recovery device to exchange heat with the mixed material in the material mixing tank. As a further improvement of the present invention, a mixing tank output pump, an inoculator and a heater are sequentially arranged on the connecting pipeline between the material mixing tank and the anaerobic digestion tank, and the sludge filtrate and kitchen liquid mixture in the material mixing tank enters the anaerobic digestion tank through the mixing tank output pump via the inoculator and the heater. As a further improvement of the present invention, a biogas stirring tube and a thermometer are provided in the anaerobic digester. The biogas stirring tube is used to achieve uniform stirring of the fermented material in the anaerobic digester, and the thermometer is used to monitor the temperature of the fermented material in real time. A biogas outlet is provided on the top of the anaerobic digester. As a further improvement of the present invention, a circulating discharge pump is provided on the connecting pipeline between the anaerobic digester and the cyclone separator, and the outlet end of the circulating discharge pump is respectively connected to the front end of the inoculator and the cyclone separator to realize the circulation of the fermented material into the anaerobic digester, or into the cyclone separator for solid-liquid separation. As a further improvement of the present invention, a sewage output pump is provided on the connecting pipeline between the sewage storage tank and the nitrite reaction tank; and the nitrite reaction tank is connected to a blower. As a general technical concept, the present invention also provides a treatment method based on the above-mentioned sludge filtrate and kitchen liquid co-fermentation treatment system, comprising the following steps: Step S1, high pH sludge filtrate and kitchen liquid enter a material mixing tank according to a preset ratio, and are stirred and mixed evenly to obtain a mixed material; Step S2, the mixed material in the material mixing tank is transported to the upper part of the anaerobic digestion tank through the mixing tank output pump, and anaerobically fermented in the anaerobic digestion tank to form biogas and fermented material; Step S3, the fermented material in the anaerobic digester is transported by a circulating discharge pump, a part of the fermented material returns to the front end of the inoculator, circulates to the anaerobic digester after passing through the inoculator and the heater, and the other part of the fermented material enters the cyclone separator for primary solid-liquid separation, and the sewage separated from the upper part of the cyclone separator enters the solid-liquid separation tank for secondary solid-liquid separation; Step S4, the concentrated fermentation products collected at the bottom of the cyclone separator and the bottom of the solid-liquid separation tank enter the sludge alkaline conditioning and dehydration unit for treatment, and the upper clear liquid of the solid-liquid separation tank enters the sewage storage tank for buffering; Step S5, a part of the sewage in the sewage storage tank enters the waste heat recovery device to exchange heat with the mixed material in the material mixing tank, and another part of the sewage in the sewage storage tank is transported to the nitrite reaction tank through the sewage output pump; Step S6: The blower supplies the required air volume to the nitrite reaction pool to convert part of the ammonia nitrogen in the sewage into nitrite nitrogen and convert c(NO2 - ) / c(NH4 + ) concentration ratio is controlled within the preset range; the clear liquid from the nitrite reaction pool enters the anaerobic ammonium oxidation reaction pool, and the SBR mode is adopted. The nitrite reaction pool and the anaerobic ammonium oxidation reaction pool are operated alternately to convert NH4 + With NO2 - It is simultaneously converted into nitrogen to complete the denitrification reaction, and the tail water is discharged into the municipal sewage network after meeting the standards. As a further improvement of the present invention, in step S1, the mixing ratio of the sludge filtrate to the kitchen liquid is 1 to 3:1; and the residence time of the mixed material in the material mixing tank is 6 h to 12 h. As a further improvement of the present invention, in step S2, the height-to-diameter ratio of the anaerobic digestion tank is 1-2:1, the operating temperature of the anaerobic digestion tank is 53° C.-56° C., and the reaction time is 8 d-20 d. As a further improvement of the present invention, in step S3, the ratio of the flow rate of the circulating discharge pump to the feed flow rate of the anaerobic digestion tank is 1:4-6; the inlet flow rate of the cyclone separator is 2 m / s-5 m / s; and the residence time of the sewage in the solid-liquid separation tank is 2h-6h. As a further improvement of the present invention, in step S6, the water temperature of the nitrite reaction tank is 35°C to 37°C, the MLSS is 10 g / L to 15 g / L, and the volume load is 0.5 kgTN / m 3 / d~1.0kgTN / m 3 / d, DO is 1.5 mg / L~2.5 mg / L, c(NO2 - ) / c(NH4 + ) is 1.2-1.4:1; the volume load of the anaerobic ammonium oxidation reaction tank is 0.5kgTN / m 3 / d~1.0kgTN / m3 / d. Compared with the prior art, the advantages of the present invention are: The sludge filtrate and kitchen liquid co-fermentation treatment system and treatment method of the present invention balance the pH and C / N ratio of the two waste liquids by organically combining high-pH sludge filtrate with high-organic acid and high-C / N ratio kitchen liquid for co-fermentation, and combining with an anaerobic fermentation system, thereby achieving a synergistic effect. The fermented wastewater is treated in combination with an anaerobic ammonia oxidation process, and there is no need to perform acidification and neutralization treatment on the high-pH sludge filtrate, thereby improving the co-fermentation efficiency and operation economy, achieving waste treatment with waste, and having the advantages of high integration, good effect, environmental protection, energy saving, and energy self-sufficiency, and solving the problems of acidification, low biodegradability, and poor stability in the separate fermentation process of sludge filtrate and kitchen liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic diagram of the structural principle of the sludge filtrate and kitchen liquid co-fermentation treatment system in a specific embodiment of the present invention; Figure 2 It is a schematic diagram of the process of co-fermentation treatment of sludge filtrate and kitchen liquid in a specific embodiment of the present invention; Legend: 1. Material mixing tank; 11. Sludge filtrate pipe; 12. Kitchen liquid pipe; 13. Mixer; 14. Mixing tank output pump; 2. Anaerobic digester; 21. Circulation discharge pump; 22. Biogas mixing pipe; 23. Thermometer; 24. Biogas outlet; 25. Inoculator; 26. Heater; 31. Cyclone separator; 32. Solid-liquid separation tank; 4. Sewage storage tank; 41. Sewage output pump; 42. Waste heat recovery device; 51. Nitrite reaction tank; 52. Anaerobic ammonia oxidation reaction tank; 53. Blower; L1. Concentrated fermentation product; L2. Tail water. DETAILED DESCRIPTION

[0007] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0008] In the description of the present invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0009] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0010] Example 1 like Figure 1 As shown, the sludge filtrate and kitchen liquid co-fermentation treatment system of the present invention comprises a material mixing tank 1, an anaerobic digestion tank 2, a cyclone separator 31, a solid-liquid separation tank 32, a sewage storage tank 4, a nitrite reaction tank 51 and an anaerobic ammonia oxidation reaction tank 52 which are sequentially connected by pipelines. The material mixing tank 1 is used to achieve uniform mixing of the sludge filtrate with a pH value of 11 to 12 produced by alkaline conditioning and dehydration of municipal sludge and the kitchen liquid after three-phase separation of kitchen waste, the anaerobic digestion tank 2 is used to achieve anaerobic digestion reaction of the sludge filtrate and the kitchen liquid to produce biogas, the cyclone separator 31 and the solid-liquid separation tank 32 are used to achieve secondary solid-liquid separation of the fermented material produced in the anaerobic digestion tank 2, and the separated sewage enters the sewage storage tank 4 for buffering. Part of the sewage in the sewage storage tank 4 enters the nitrite reaction tank 51 and the anaerobic ammonia oxidation reaction tank 52 in turn for purification treatment, and the resulting tail water L2 is discharged into the municipal sewage network after meeting the standards, and another part of the sewage in the sewage storage tank 4 enters the waste heat recovery device 42 to exchange heat with the mixed material in the material mixing tank 1. The sewage in the sewage storage tank 4 exchanges heat with the material in the material mixing tank 1 in the waste heat recovery device 42, which, on the one hand, reduces the sewage water temperature to meet the requirements of the subsequent nitrite reaction tank 51, and on the other hand, increases the temperature in the material mixing tank 1, reduces the energy consumption of the heater, and realizes heat source recovery.

[0011] In this embodiment, by organically combining high pH sludge filtrate with high organic acid and high C / N ratio restaurant slurry for co-fermentation, and combining with an anaerobic fermentation system, the pH and C / N ratio of the two waste liquids are balanced, achieving a synergistic effect, and the fermented wastewater is treated in combination with the anaerobic ammonia oxidation process, without the need for acidification and neutralization treatment of the high pH sludge filtrate, thereby improving the co-fermentation efficiency and operating economy, achieving waste treatment with waste, having the advantages of high integration, good effect, environmental protection, energy saving, and energy self-sufficiency, and solving the problems of acidification, low biodegradability, and poor stability that exist in the separate fermentation process of sludge filtrate and restaurant slurry.

[0012] like Figure 1As shown, a sludge filtrate pipe 11 and a kitchen liquid pipe 12 are provided on the top of the material mixing tank 1 to allow the sludge filtrate and the kitchen liquid to be fed into the material mixing tank 1. A stirrer 13 is provided in the material mixing tank 1. The two waste liquids are fully mixed under the action of the stirrer 13. On the one hand, the alkalinity in the sludge filtrate is neutralized with the organic acid in the kitchen liquid to adjust the pH, and on the other hand, the C / N ratio of the two can be adjusted to an appropriate range.

[0013] The connecting pipe between the material mixing tank 1 and the anaerobic digestion tank 2 is provided with a mixing tank output pump 14, an inoculator 25 and a heater 26 in sequence, and the sludge filtrate and the kitchen liquid mixture in the material mixing tank 1 enter the upper part of the anaerobic digestion tank 2 through the mixing tank output pump 14, the inoculator 25 and the heater 26. The heater 26 is used to control the material temperature in the anaerobic digestion tank 2 to maintain it within the process requirement range.

[0014] like Figure 1 As shown, the anaerobic digestion tank 2 is provided with a biogas stirring pipe 22 and a thermometer 23. The biogas stirring pipe 22 is used to achieve uniform stirring of the fermented material in the anaerobic digestion tank 2, and the thermometer 23 is used to monitor the temperature of the fermented material in real time. A biogas outlet 24 is provided on the top of the anaerobic digestion tank 2, and the biogas produced by the fermentation is discharged from the biogas outlet 24. A part of the biogas is pressurized and circulated to the biogas stirring pipe 22, and a part of the biogas is used for biogas power generation to supply the energy consumption of the blower of the back-end sewage treatment.

[0015] like Figure 1 As shown, a circulating discharge pump 21 is provided on the connecting pipe between the anaerobic digestion tank 2 and the cyclone separator 31. The outlet ends of the circulating discharge pump 21 are respectively connected to the front end of the inoculator 25 and the cyclone separator 31, so as to realize the circulation of the fermented material into the anaerobic digestion tank 2, or enter the cyclone separator 31 for solid-liquid separation. Specifically, the discharge end of the circulating discharge pump 21 is divided into two branches, one of which enters the front end of the inoculator 25, so that the fermented material in the anaerobic digestion tank 2 and the feed are mixed and inoculated in the inoculator 25 and then returned to the anaerobic digestion tank 2 through the heater 26, and the other enters the cyclone separator 31, and the flow rate entering the cyclone separator 31 is consistent with the feed flow rate of the anaerobic digestion tank 2, so as to keep the liquid level in the tank stable.

[0016] In this embodiment, the biogas in the biogas stirring pipe 22 rises from the lower part to the upper part of the anaerobic digestion tank 2 to carry the mixture of the materials in the tank, and combined with the circulation of the circulating discharge pump 21, the materials in the tank are in a completely mixed state, and combined with the upper feeding and bottom discharging operation mode, it plays a role in preventing the sedimentation of materials at the bottom of the anaerobic digestion tank 2, and improves the material mixing and fermentation efficiency. The organic matter in the sludge filtrate and the kitchen liquid is decomposed and converted into biogas by the anaerobic bacteria in the anaerobic digestion tank 2, and the organic nitrogen is converted into ammonium radicals. At the same time, the solid content in the tank is reduced. Due to the adjustment of the carbon-nitrogen ratio and pH by the mixing of the two waste liquids, the acid-base balance system in the anaerobic digestion tank 2 remains stable.

[0017] like Figure 1 As shown, a sewage output pump 41 is provided on the connecting pipe between the sewage storage tank 4 and the nitrification reaction tank 51. The nitrification reaction tank 51 is connected to a blower 53, and the blower 53 supplies the nitrification reaction tank 51 with the required air volume.

[0018] like Figure 2 As shown, this embodiment also provides a treatment method based on the above-mentioned sludge filtrate and kitchen liquid co-fermentation treatment system, comprising the following steps: Step S1, high pH sludge filtrate and kitchen liquid enter the material mixing tank 1 according to a preset ratio, and are stirred and mixed evenly to obtain a mixed material.

[0019] Step S2: The mixed material in the material mixing tank 1 is transported to the upper part of the anaerobic digestion tank 2 via the mixing tank output pump 14, and anaerobically fermented in the anaerobic digestion tank 2 to form biogas and fermented material.

[0020] Step S3, the fermented material in the anaerobic digester 2 is transported by the circulating discharge pump 21, a part of the fermented material returns to the front end of the inoculator 25, and circulates to the anaerobic digester 2 after passing through the inoculator 25 and the heater 26, and the other part of the fermented material enters the cyclone separator 31 for primary solid-liquid separation, and the sewage separated from the upper part of the cyclone separator 31 enters the solid-liquid separation tank 32 for secondary solid-liquid separation.

[0021] Step S4, the concentrated fermentation product L1 collected at the bottom of the cyclone separator 31 and the bottom of the solid-liquid separation tank 32 enters the sludge alkaline conditioning and dehydration unit for treatment, and the upper clear liquid of the solid-liquid separation tank 32 enters the sewage storage tank 4 for buffering.

[0022] Step S5, a part of the sewage in the sewage storage tank 4 enters the waste heat recovery device 42 to exchange heat with the mixed material in the material mixing tank 1, and another part of the sewage in the sewage storage tank 4 is transported to the nitrite reaction tank 51 through the sewage output pump 41.

[0023] Step S6: The blower 53 supplies the required air volume to the nitrite reaction pool 51 to convert part of the ammonia nitrogen in the sewage into nitrite nitrogen and convert c(NO2 - ) / c(NH4 + ) concentration ratio is controlled within a preset range, and the residual organic matter is decomposed at the same time; the clear liquid of the nitrite reaction tank 51 enters the anaerobic ammonium oxidation reaction tank 52, and the SBR mode is adopted. The nitrite reaction tank 51 and the anaerobic ammonium oxidation reaction tank 52 are operated alternately to convert NH4 + With NO2 - It is simultaneously converted into nitrogen to complete the denitrification reaction, and the tail water L2 is discharged into the municipal sewage network after meeting the "Comprehensive Sewage Discharge Standard" (GB8978-1996).

[0024] In step S1 of this embodiment, the mixing ratio of the sludge filtrate to the kitchen liquid is 1-3:1; and the residence time of the mixed material in the material mixing tank 1 is 6 h-12 h.

[0025] In step S2 of this embodiment, the height-to-diameter ratio of the anaerobic digestion tank 2 is 1-2:1, the operating temperature of the anaerobic digestion tank 2 is 53° C.-56° C., and the reaction time is 8 d-20 d.

[0026] In step S3 of this embodiment, the ratio of the flow rate of the circulating discharge pump 21 to the feed flow rate of the anaerobic digestion tank 2 is 1:4-6; the inlet flow rate of the cyclone separator 31 is 2 m / s-5 m / s; and the residence time of the sewage in the solid-liquid separation tank 32 is 2h-6h.

[0027] In step S6 of this embodiment, the water temperature of the nitrification reaction tank 51 is 35°C to 37°C, the MLSS is 10 g / L to 15 g / L, and the volume load is 0.5 kgTN / m 3 / d~1.0kgTN / m 3 / d, DO is 1.5 mg / L~2.5 mg / L, c(NO2 - ) / c(NH4 + ) is 1.2-1.4:1; the volume load of the anaerobic ammonium oxidation reaction tank 52 is 0.5 kgTN / m 3 / d~1.0kgTN / m 3 / d.

[0028] Example 2 The water quality of the filtrate produced by alkaline conditioning of a certain sludge + plate and frame dehydration is: pH 12.0, ammonia nitrogen 750mg / L, TN 2000mg / L, COD 25000mg / L, SS 500mg / L. The kitchen waste is an aqueous slurry obtained by multi-stage crushing and sorting - high-temperature cooking - three-phase separation of kitchen waste, with pH 3.5, organic acid 20000mg / L, ammonia nitrogen 165mg / L, total nitrogen 2400mg / L, COD 90000mg / L, and solid content 15%.

[0029] The sludge filtrate and the kitchen liquid are continuously fed into the material mixing tank 1 in a ratio of 2:1, and are continuously pumped into the anaerobic digestion tank 2 after being stirred in the tank for 6 hours. The height-to-diameter ratio of the anaerobic digestion tank 2 is 1.3, and the bottom of the anaerobic digestion tank 2 is conical. The residence time of the mixture of the sludge filtrate and the kitchen liquid in the anaerobic digestion tank 2 is 12 days, and the temperature in the tank is controlled at 55°C by the heater 26. The flow rate of the circulating discharge pump 21 at the bottom of the anaerobic digestion tank 2 is 5 times the sum of the flow rates of the sludge filtrate and the kitchen liquid. The outlet of the circulating discharge pump 21 enters the cyclone separator 31 and the front end of the inoculator 25 respectively, and the flow rate ratio is 1:4. The biogas stirring pipes 22 are evenly arranged, and the biogas flow rate is 6m / s. The generated biogas is discharged through the biogas outlet 24, and the materials in the anaerobic digestion tank 2 are in a completely mixed state.

[0030] The inlet flow rate of the fermentation material entering the cyclone separator 31 is controlled to be 4m / s, the residence time of the solid-liquid separation tank 32 is 3h, and the sewage in the sewage storage tank 4 and the mixed material in the material mixing tank 1 are heat-exchanged in the waste heat recovery device 42. After the heat exchange, the water temperature of the sewage storage tank 4 drops from 48°C to 36°C, and the waste liquid temperature of the material mixing tank 1 rises from 30°C to 40°C, realizing heat recovery and improving energy consumption economy. The concentrated fermentation product L1 separated at the bottom of the cyclone separator 31 and the bottom of the solid-liquid separation tank 32 enters the sludge alkaline conditioning and dehydration unit for treatment together, and the sewage in the sewage storage tank 4 enters the nitrite reaction tank 51.

[0031] The water temperature in the nitrite reaction tank 51 is controlled at 36°C, the MLSS is 10g / L, the blower 53 controls the DO in the tank to 1.5mg / L, and the inlet load is 0.6 kgTN / m 3 / d, the effluent enters the anaerobic ammonium oxidation reaction tank 52, and the volume load of the anaerobic ammonium oxidation reaction tank 52 is 0.8kgTN / m 3 / d, the denitrification reaction is completed, and the tail water L2 meets the "Comprehensive Sewage Discharge Standard" (GB8978-1996) and is discharged into the municipal sewage network.

[0032] The test data of each reactor are listed in the following Table 1: Table 1 Records of various test data during implementation

[0033] From the data in Table 1, it can be seen that the sludge filtrate and the kitchen liquid are mixed in a ratio of 2:1, and the calculated C / N ratio of the mixture is 21.8, which is between 20 and 30 for the anaerobic fermentation process. At the same time, the pH of the mixture is balanced to 5.1. The high pH sludge filtrate is reduced by neutralization, and no acid addition is required. In the anaerobic digester 2, due to the degradation of organic matter, the solid content is reduced from 5% to 3%, and the organic nitrogen contained in the sludge filtrate and the kitchen liquid is converted into ammonia nitrogen, which increases the ammonia nitrogen content. The acid-base ratio in the anaerobic digester 2 is 0.2 and the pH is 8.1. It is generally shown that the acid-base balance system and biochemical performance indicators in the system are in normal state. At the same time, the COD degradation rate in the anaerobic digester 2 reached 93%, which is higher than the anaerobic fermentation degree of the sludge filtrate and the kitchen liquid alone; the unit feed biogas production rate is 33m 3 / t, which is higher than the theoretical gas production rate of the mixture of two wastewaters, indicating that this method improves the co-fermentation efficiency.

[0034] After the fermentation material passes through the cyclone separator 31 and the solid-liquid separation tank 32, the wastewater SS is 500 mg / L and the C / N ratio is 1.5, which belongs to low C / N ratio wastewater and is suitable for anaerobic ammonium oxidation process treatment. Through nitrite + anaerobic ammonium oxidation process treatment, the c (NO2 - ) / c(NH4 + ) is 1.3, which is close to the theoretical value, and enters the anaerobic ammonium oxidation reaction tank 52, NH4 + and NO2 - The total removal rate reached 99.3%, and the system load reached 0.8kgTN / m 3 / d, no need to supplement organic carbon source, the required electricity comes from the biogas power generation in anaerobic digester 2, which has the characteristics of energy saving and consumption reduction and high operation economy.

[0035] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A sludge filtrate and kitchen liquid co-fermentation treatment system, characterized in that: The invention comprises a material mixing tank (1), an anaerobic digestion tank (2), a cyclone separator (31), a solid-liquid separation tank (32), a sewage storage tank (4), a nitrite reaction tank (51) and an anaerobic ammonia oxidation reaction tank (52) which are sequentially connected by pipelines; the material mixing tank (1) is used to achieve uniform mixing of high-pH sludge filtrate produced by alkaline conditioning and dehydration of municipal sludge and food liquid after three-phase separation of food waste; the anaerobic digestion tank (2) is used to achieve anaerobic digestion reaction of the sludge filtrate and the food liquid to produce biogas; the cyclone separator (31) is used to achieve uniform mixing of high-pH sludge filtrate produced by alkaline conditioning and dehydration of municipal sludge and food liquid after three-phase separation of food waste; 1) and the solid-liquid separation tank (32) are used to achieve secondary solid-liquid separation of the fermented material produced in the anaerobic digestion tank (2); the separated sewage enters the sewage storage tank (4) for buffering; a portion of the sewage in the sewage storage tank (4) enters the nitrite reaction tank (51) and the anaerobic ammonia oxidation reaction tank (52) in sequence for purification treatment; the obtained tail water (L2) is discharged into the municipal sewage network after meeting the standards; another portion of the sewage in the sewage storage tank (4) enters the waste heat recovery device (42) for heat exchange with the mixed material in the material mixing tank (1).

2. The sludge filtrate and kitchen liquid co-fermentation treatment system according to claim 1, characterized in that: A mixing tank output pump (14), an inoculator (25) and a heater (26) are sequentially arranged on the connecting pipe between the material mixing tank (1) and the anaerobic digestion tank (2); the sludge filtrate and kitchen liquid mixture in the material mixing tank (1) enters the anaerobic digestion tank (2) through the mixing tank output pump (14) and the inoculator (25) and the heater (26).

3. The sludge filtrate and kitchen liquid co-fermentation treatment system according to claim 2, characterized in that: The anaerobic digestion tank (2) is provided with a biogas stirring pipe (22) and a thermometer (23); the biogas stirring pipe (22) is used to achieve uniform stirring of the fermented material in the anaerobic digestion tank (2); and the thermometer (23) is used to monitor the temperature of the fermented material in real time; and a biogas outlet (24) is provided at the top of the anaerobic digestion tank (2).

4. The sludge filtrate and kitchen liquid co-fermentation treatment system according to claim 3, characterized in that: A circulating discharge pump (21) is provided on the connecting pipe between the anaerobic digestion tank (2) and the cyclone separator (31), and the outlet end of the circulating discharge pump (21) is respectively connected to the front end of the inoculator (25) and the cyclone separator (31), so as to realize the circulation of fermented materials into the anaerobic digestion tank (2), or into the cyclone separator (31) for solid-liquid separation.

5. The sludge filtrate and kitchen liquid co-fermentation treatment system according to claim 4, characterized in that: A sewage output pump (41) is provided on the connecting pipe between the sewage storage tank (4) and the nitrite reaction tank (51); and the nitrite reaction tank (51) is connected to a blower (53).

6. A treatment method based on the sludge filtrate and kitchen liquid co-fermentation treatment system according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1, high pH sludge filtrate and kitchen liquid enter a material mixing tank (1) according to a preset ratio, and are stirred and mixed evenly to obtain a mixed material; Step S2, the mixed material in the material mixing tank (1) is transported to the upper part of the anaerobic digestion tank (2) via the mixing tank output pump (14), and anaerobically fermented in the anaerobic digestion tank (2) to form biogas and fermented material; Step S3, the fermented material in the anaerobic digestion tank (2) is transported by the circulating discharge pump (21), a part of the fermented material returns to the front end of the inoculator (25), and circulates to the anaerobic digestion tank (2) after passing through the inoculator (25) and the heater (26), and another part of the fermented material enters the cyclone separator (31) for primary solid-liquid separation, and the sewage separated at the top of the cyclone separator (31) enters the solid-liquid separation tank (32) for secondary solid-liquid separation; Step S4, the concentrated fermentation product (L1) collected at the bottom of the cyclone separator (31) and the bottom of the solid-liquid separation tank (32) enters the sludge alkaline conditioning and dehydration unit for treatment, and the upper clear liquid of the solid-liquid separation tank (32) enters the sewage storage tank (4) for buffering; Step S5, a portion of the sewage in the sewage storage tank (4) enters the waste heat recovery device (42) to exchange heat with the mixed material in the material mixing tank (1), and another portion of the sewage in the sewage storage tank (4) is transported to the nitrite reaction tank (51) through the sewage output pump (41); Step S6: The blower (53) supplies the required air volume to the nitrite reaction tank (51), converting part of the ammonia nitrogen in the sewage into nitrite nitrogen and converting c(NO2 - ) / c(NH4 + ) concentration ratio is controlled within a preset range; the clear liquid from the nitrite reaction tank (51) enters the anaerobic ammonium oxidation reaction tank (52), and the SBR mode is adopted, and the nitrite reaction tank (51) and the anaerobic ammonium oxidation reaction tank (52) are operated alternately to convert NH4 + With NO2 - It is simultaneously converted into nitrogen to complete the denitrification reaction, and the tail water (L2) is discharged into the municipal sewage network after meeting the standards.

7. The processing method according to claim 6, characterized in that In step S1, the mixing ratio of the sludge filtrate to the kitchen liquid is 1 to 3:1; and the residence time of the mixed material in the material mixing tank (1) is 6 hours to 12 hours.

8. The processing method according to claim 6, characterized in that In step S2, the height-to-diameter ratio of the anaerobic digestion tank (2) is 1 to 2:1, the operating temperature of the anaerobic digestion tank (2) is 53° C. to 56° C., and the reaction time is 8 days to 20 days.

9. The processing method according to claim 6, characterized in that In step S3, the ratio of the flow rate of the circulating discharge pump (21) to the feed flow rate of the anaerobic digestion tank (2) is 1:4-6; the inlet flow rate of the cyclone separator (31) is 2 m / s-5 m / s; and the residence time of the sewage in the solid-liquid separation tank (32) is 2 h-6 h.

10. The processing method according to claim 6, characterized in that In step S6, the water temperature of the nitrite reaction tank (51) is 35°C to 37°C, the MLSS is 10 g / L to 15 g / L, and the volume load is 0.5 kgTN / m 3 / d~1.0kgTN / m 3 / d, DO is 1.5 mg / L~2.5 mg / L, c(NO2 - ) / c(NH4 + ) is 1.2-1.4:1; the volume load of the anaerobic ammonium oxidation reaction tank (52) is 0.5 kgTN / m 3 / d~1.0kgTN / m 3 / d.

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