A dyeing and printing wastewater treatment system based on sulfur autotrophic denitrification coupled with biofilm

Abstract

This utility model relates to the field of industrial wastewater treatment technology, specifically a dyeing and printing wastewater treatment system based on sulfur autotrophic denitrification coupled with biofilm. The system includes an aerobic treatment unit, an intermediate sedimentation unit, and an anaerobic treatment unit arranged sequentially from left to right. The aerobic treatment unit includes an aerobic tank, with a first water distribution pipe installed at the bottom and a microporous aerator located inside the first water distribution pipe. Two parallel baffles are fixed above the microporous aerator in the aerobic tank, forming an aeration channel between the baffles. Several BF packing biofilms are installed at the ends of the two baffles furthest from the aeration channel. This dyeing and printing wastewater treatment system based on sulfur autotrophic denitrification coupled with biofilm avoids competition for substrate between sulfur autotrophic denitrifying bacteria and anaerobic ammonia-oxidizing bacteria, thus preventing inhibition, while achieving efficient nitrogen and sulfur removal. The use of a porous structure layer combining BF packing biofilm and BM biofilm packing prevents biofilm detachment.

Description

Technical Field

[0001] This utility model relates to the field of industrial wastewater treatment technology, specifically a dyeing and printing wastewater treatment system based on sulfur autotrophic denitrification coupled with biofilm. Background Technology

[0002] Dyeing and printing wastewater often contains large amounts of nitrate nitrogen and sulfides due to processes such as dye reduction and the use of auxiliaries. The use of vat dyes or anti-reduction treatments can lead to the accumulation of nitrate ions, while also producing high concentrations of reduced sulfur (such as sulfides and sulfites). This type of dyeing and printing wastewater typically has the following characteristics: high concentrations of sulfides (S... 2- It contains 150-400 mg / L of ammonia nitrogen (NH3-N, 30-70 mg / L) and persistent organic pollutants (COD 500-2000 mg / L), and has an imbalanced C / N ratio and strong toxic inhibitory effect.

[0003] In existing technologies, physicochemical methods (such as ferrous salt precipitation and ozone oxidation) can quickly remove sulfides, but they require the addition of large amounts of chemical reagents (FeSO4 dosage reaches 0.5-1.2 kg / m³). 3 This leads to a 30%-50% increase in sludge production and fails to address nitrate (NO3) levels. - -N) pollution problems. The commonly used traditional heterotrophic denitrification process relies on exogenous carbon sources (methanol, sodium acetate, etc.) to maintain denitrification efficiency. When the carbon-to-nitrogen ratio (C / N) is below 4, the denitrification rate drops to below 50%, and carbon source costs account for 40%-60% of the total operating costs. Furthermore, reducing sulfur components in wastewater not only inhibit conventional nitrification systems but also easily cause odor release and system acidification in biological systems, further exacerbating treatment difficulties and resulting in low denitrification and desulfurization efficiency.

[0004] In recent years, sulfur autotrophic denitrification technology has gradually attracted attention as an emerging nitrogen removal technology because it can efficiently reduce nitrates under conditions without organic carbon sources. Sulfur autotrophic denitrification technology uses elemental sulfur or reduced sulfur as electron donors and utilizes autotrophic denitrifying bacteria (such as Thiobacillus) for biological nitrogen removal. The specific reaction formula is: 5S + 6NO3 - +2H₂O→3N₂+5SO₄ 2- +4H + It has advantages such as requiring no external carbon source, controllable byproducts, and strong applicability. However, there are two major bottlenecks in practical applications: firstly, sulfide concentrations exceeding 80 mg / L have a toxic inhibitory effect on denitrifying bacteria (IC50). 50=50-80mg / L); secondly, the biofilm is prone to detachment, leading to unstable bacterial activity (activity fluctuation range of 30%-50%). Although the MBR coupling process proposed by invention patent CN108821515A can increase sludge concentration, its flat plate membrane is prone to clogging, backwashing energy consumption is high, and the problem of metabolic competition between sulfur autotrophic bacteria and heterotrophic bacteria has not been solved. Utility Model Content

[0005] The purpose of this invention is to provide a dyeing and printing wastewater treatment system based on sulfur autotrophic denitrification coupled with biofilm. This system has a simple structure and reasonable design, which avoids the inhibition caused by competition for substrate between sulfur autotrophic denitrifying bacteria and anaerobic ammonia oxidizing bacteria, and can achieve efficient nitrogen and sulfur removal. It adopts a porous structure layer combining BF packing biofilm and BM biofilm packing to avoid biofilm detachment, effectively increase the attachment area of ​​microorganisms, significantly reduce sludge loss, and significantly improve pollutant removal efficiency. It can achieve the advantages of efficient conversion and removal of ammonia nitrogen and sulfide removal, and solves the problems mentioned in the above technical background.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a dyeing and printing wastewater treatment system based on sulfur autotrophic denitrification coupled with biofilm, the system comprising an aerobic treatment unit, an intermediate sedimentation unit and an anaerobic treatment unit arranged from left to right;

[0007] The aerobic treatment unit includes an aerobic tank. A first water distribution pipe and a microporous aerator located inside the first water distribution pipe are installed at the bottom of the aerobic tank. Two parallel baffles are fixed above the microporous aerator in the aerobic tank, forming an aeration channel between the baffles. Several BF packing biofilms are installed at the ends of the two baffles away from the aeration channel.

[0008] The intermediate sedimentation unit includes a sedimentation tank, in which an inclined tube honeycomb packing layer and a conical sludge hopper located below the inclined tube honeycomb packing layer are installed.

[0009] The anaerobic treatment unit includes an anaerobic tank, in which a second water distribution pipe, a BM packing biofilm, and a porous structure layer are arranged sequentially from bottom to top. The outlet end of the second water distribution pipe is radial. Both the second water distribution pipe and the porous structure layer are located inside the anaerobic tank. Several BM packing biofilms are arranged and distributed between the second water distribution pipe and the porous structure layer.

[0010] Preferably, the system further includes a pretreatment unit located at the end of the aerobic treatment unit away from the anaerobic treatment unit. The pretreatment unit includes an equalization tank, inside which a vertically arranged grid plate is fixed. The grid plate has several evenly distributed through holes that can intercept large particulate impurities.

[0011] Preferably, the pretreatment unit further includes a lift pump, which is fixed at one end of the equalization tank near the aerobic tank, and the equalization tank is connected to the aerobic tank through the lift pump.

[0012] Preferably, the aerobic treatment unit further includes a first screw pump, which is installed at one end of the aerobic tank near the sedimentation tank and is connected to the sedimentation tank.

[0013] Preferably, the intermediate sedimentation unit further includes a second screw pump and a third screw pump. The second screw pump is installed on the lower end face of the sedimentation tank, and the end of the second screw pump away from the sedimentation tank is connected to the aerobic tank. The third screw pump is installed on the end of the sedimentation tank close to the anaerobic tank, and the third screw pump is connected to the anaerobic tank.

[0014] Preferably, the BF packing biofilm is spherical, while the BM packing biofilm is disc-shaped.

[0015] Preferably, the anaerobic treatment unit further includes a gas-liquid separation device, which is fixed to the top of the anaerobic tank.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] 1. This utility model provides a dyeing and printing wastewater treatment system based on sulfur autotrophic denitrification coupled with biofilm. This system includes an aerobic treatment unit, an intermediate sedimentation unit, and an anaerobic treatment unit arranged from left to right. The overall structure is simple and rationally designed. The aerobic treatment unit includes an aerobic tank with a first water distribution pipe and a microporous aerator located inside the first water distribution pipe at the bottom. Two parallel baffles are fixed above the microporous aerator in the aerobic tank, forming an aeration channel between the baffles. Several BF packing biofilms are installed at the ends of the two baffles away from the aeration channel. The anaerobic treatment unit includes an anaerobic tank with a second water distribution pipe, a BM packing biofilm, and a porous structure layer arranged from bottom to top. By constructing a composite microbial synergistic system, the aerobic treatment unit completes the oxidative decomposition of organic matter and partial conversion of sulfides, providing suitable sulfide forms (S, S2O3) for the subsequent anaerobic treatment unit. 2- The nitrogen oxides (NO2--N, NO3--N) form avoids the inhibition caused by competition for substrates between sulfur autotrophic denitrifying bacteria and anaerobic ammonia oxidizing bacteria, and can achieve efficient nitrogen and sulfur removal, making it suitable for widespread use.

[0018] 2. This utility model uses a porous structure layer combining BF packing biofilm and BM biofilm packing to avoid biofilm detachment, effectively increase the attachment area of ​​microorganisms, significantly reduce sludge loss, and significantly improve pollutant removal efficiency.

[0019] 3. In operation, this utility model can achieve efficient conversion and removal of ammonia nitrogen and removal of sulfides without the need to add an external carbon source. Compared with conventional nitrification processes, it reduces oxygen consumption by about 40% and sludge generation by more than 40%, significantly reducing operating costs and making it suitable for upgrading and retrofitting existing sewage treatment facilities. Attached Figure Description

[0020] Figure 1 This is the front view of the present utility model;

[0021] Figure 2 This is a schematic diagram of the reaction process of this utility model.

[0022] The reference numerals and names in the diagram are as follows: 1. Pretreatment unit; 11. Equalization tank; 12. Grating plate; 13. Through hole; 14. Lift pump; 2. Aerobic treatment unit; 21. Aerobic tank; 22. First water distribution pipe; 23. Microporous aerator; 24. Baffle; 25. Aeration channel; 26. BF packing biofilm; 27. First screw pump; 3. Intermediate sedimentation unit; 31. Sedimentation tank; 32. Inclined tube honeycomb packing layer; 33. Conical sludge hopper; 34. Second screw pump; 35. Third screw pump; 4. Anaerobic treatment unit; 41. Anaerobic tank; 42. Second water distribution pipe; 43. BM packing biofilm; 44. Porous structure layer; 45. Gas-liquid separation device. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] In the description of the embodiments of this utility model, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the embodiments of this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0025] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention according to the specific circumstances.

[0026] Please see Figure 1 The present invention provides an embodiment of a dyeing and printing wastewater treatment system based on sulfur autotrophic denitrification and biofilm coupling. The system includes an aerobic treatment unit 2, an intermediate sedimentation unit 3 and an anaerobic treatment unit 4 arranged from left to right. A pretreatment unit 1 is provided at the end of the aerobic treatment unit 2 away from the anaerobic treatment unit 4.

[0027] Please see Figure 2The pretreatment unit 1 includes an equalization tank 11, inside which a vertically arranged grid plate 12 is fixed. Several evenly distributed through holes 13 are provided on the grid plate 12, which can intercept large particulate impurities. The depth of the through holes 13 is 3mm. The pretreatment unit 1 also includes a lift pump 14. The aerobic treatment unit 2 includes an aerobic tank 21. The lift pump 14 is fixed at one end of the equalization tank 11 near the aerobic tank 21. The equalization tank 11 is connected to the aerobic tank 21 through the lift pump 14. A first water distribution pipe 22 and a microporous aerator 23 located inside the first water distribution pipe 22 are installed at the bottom of the aerobic tank 21. Two parallel baffles 24 are fixed above the microporous aerator 23 in the aerobic tank 21. An aeration channel 25 is formed between the baffles 24. Several BF packing biofilms 26 are provided at the ends of the two baffles 24 away from the aeration channel 25. The aerobic treatment unit 2 also includes a first screw pump 27.

[0028] Please refer to it again. Figure 2 The intermediate sedimentation unit 3 includes a sedimentation tank 31. A first screw pump 27 is installed at the end of the aerobic tank 21 near the sedimentation tank 31 and is connected to the sedimentation tank 31. An inclined tube honeycomb packing layer 32 and a conical sludge hopper 33 located below the inclined tube honeycomb packing layer 32 are installed inside the sedimentation tank 31. Furthermore, the intermediate sedimentation unit 3 also includes a second screw pump 34 and a third screw pump 35. The second screw pump 34 is installed on the lower end face of the sedimentation tank 31, and the end of the second screw pump 34 away from the sedimentation tank 31 is connected to the aerobic tank 21. The third screw pump 35 is installed at the end of the sedimentation tank 31 near the anaerobic tank 41, and the third screw pump... The rod pump 35 is connected to the anaerobic tank 41. The anaerobic treatment unit 4 includes the anaerobic tank 41. Inside the anaerobic tank 41, from bottom to top, there are arranged a second water distribution pipe 42, a BM packing biofilm 43, and a porous structure layer 44. The outlet end of the second water distribution pipe 42 is radial. Both the second water distribution pipe 42 and the porous structure layer 44 are located inside the anaerobic tank 41. The BM packing biofilm 43 is disc-shaped, and there are several BM packing biofilms 43, which are distributed between the second water distribution pipe 42 and the porous structure layer 44. The anaerobic treatment unit 4 also includes a gas-liquid separation device 45, which is fixed to the top of the anaerobic tank 41.

[0029] Working principle: Please refer to Figures 1 to 2In this invention, the system adopts a three-stage series layout. Sulfur-containing wastewater flows sequentially through a pretreatment unit 1, an aerobic treatment unit 2, an intermediate sedimentation unit 3, and an anaerobic treatment unit 4. A grid plate 12 installed in the equalization tank 11 intercepts large particulate impurities, and the equalization tank 11 is used for 2 hours to adjust the water quality and quantity. Afterwards, a lift pump 14 transports the wastewater to the aerobic treatment unit 2, where uniform water distribution is achieved through the first distribution pipe 22. The aerobic treatment unit 2 has an open structure, with a vertical aeration channel 25 formed between two baffles 24 inside. A microporous aerator 23 at the bottom generates 0.5-1.2mm microbubbles, and the middle is filled with BF packing biofilm 26. The air-water mixture flows at a velocity of 0.3 m / s. After rising to the top of the tank along the vertical aeration channel 25, the wastewater diffuses outwards and penetrates the BF packing biofilm 26, forming a circulating flow with a downward velocity of 0.05 m / s. After three cycles, the wastewater enters the intermediate sedimentation unit 3 through the top overflow port via the first screw pump 27. The intermediate sedimentation unit 3 uses a 60° inclined honeycomb packing layer 32 to accelerate sludge-water separation. The settled sludge is collected through a conical sludge hopper 33, and 30% of the sludge is returned to the front end of the aerobic tank 21 via the second screw pump 34, maintaining the system MLSS at 6000 mg / L. The supernatant in the aerobic tank 21 enters the bottom of the anaerobic treatment unit 4 via the third screw pump 35, and is evenly distributed through the bottom radial second water distribution pipe 42. The water flows upwards, passes through the BM packing biofilm 43 and the porous structure layer 44, and then exits. In addition, the top of the anaerobic treatment unit 4 is equipped with a gas-liquid separator 45 for collecting gases such as N2 and CO2.

[0030] Please refer to it again. Figures 1 to 2 The aerobic treatment unit 2 uses laboratory-grown nitrifying sludge as inoculum, and the BF packing biofilm 26 used is a white suspended ball filled with 80% hydrophobic polyurethane. The anaerobic treatment unit 4 uses laboratory-grown anaerobic ammonia oxidation-sulfur autotrophic denitrification coupled sludge, and the BM packing biofilm 43 used is a combination of hydrophobic polyurethane and K3 packing. The porous structure layer 44 is a porous support structure composed of limestone matrix, pyrite, and activated carbon matrix, with internal pore sizes controlled between 3mm and 4mm. The main function of the porous structure layer 44 is to supply inorganic carbon to autotrophic denitrifying bacteria, and secondly, to effectively retain activated sludge through physical adsorption, working together with the BM packing biofilm 43 to maintain a stable microbial biomass concentration in the anaerobic reaction. The system condition control indicators include: the dissolved oxygen (DO) value of the aerobic treatment unit is maintained between 0.5 mg / L and 1.0 mg / L, the hydraulic retention time (HRT) is between 5 h and 7 h, the sludge concentration (MLSS) value is between 5000 mg / L and 6000 mg / L, the sludge return ratio of the intermediate sedimentation unit 3 is dynamically adjusted to 25-40%, and the HRT of the anaerobic treatment unit 4 is controlled between 4.5 h and 5.5 h.

[0031]

[0032] Table 1 Raw water quality and design standards (unit: mg / L)

[0033]

[0034] Table 2 Key Operating Parameters

[0035] Operational process: Aerobic stage: Wastewater enters the aerobic tank after pretreatment by a screen, with DO maintained at 0.8±0.1 mg / L and S... 2 -Oxidized to S 0 (Conversion rate ≥ 97.5%), simultaneously completing short-cut nitration (NH3-N → NO2). - -N). Anaerobic stage: The supernatant from the sedimentation tank enters the anaerobic unit, where sulfur-autotrophic denitrifying bacteria thrive using S. 0 Reduction of NO3 by electron donor - -N, coupled Anammox reaction (NH4) + +NO2 - →N2), TN removal rate ≥92%.

[0036]

[0037] Table 3 Processing efficiency (90-day average)

[0038] This embodiment achieves stable effluent compliance through a sulfur-directed conversion and biofilm coupling mechanism. The effluent meets the requirements of the "Water Pollutant Discharge Standard for Textile Dyeing and Finishing Industry" (GB 4287-2012), and the system has strong resistance to shock loads. 2- Even when the instantaneous concentration reaches 480 mg / L, it can still maintain the effluent S 2- With a concentration of ≤1.2 mg / L, it provides an industrial solution for the treatment of high-sulfur dyeing and printing wastewater.

[0039] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A printing and dyeing wastewater treatment system based on coupling of sulfur autotrophic denitrification and biofilm, characterized in that: It includes an aerobic treatment unit (2), an intermediate sedimentation unit (3), and an anaerobic treatment unit (4) arranged from left to right; The aerobic treatment unit (2) includes an aerobic tank (21). The bottom of the aerobic tank (21) is equipped with a first water distribution pipe (22) and a microporous aerator (23) located inside the first water distribution pipe (22). There are two parallel baffles (24) fixed above the microporous aerator (23) in the aerobic tank (21). An aeration channel (25) is formed between the baffles (24). Several BF packing biofilms (26) are provided at the ends of the two baffles (24) away from the aeration channel (25). The intermediate sedimentation unit (3) includes a sedimentation tank (31), in which an inclined tube honeycomb packing layer (32) and a conical sludge hopper (33) located below the inclined tube honeycomb packing layer (32) are installed. The anaerobic treatment unit (4) includes an anaerobic tank (41). The anaerobic tank (41) is provided with a second water distribution pipe (42), a BM packing biofilm (43) and a porous structure layer (44) arranged from bottom to top. The outlet end of the second water distribution pipe (42) is radial. Both the second water distribution pipe (42) and the porous structure layer (44) are located inside the anaerobic tank (41). A number of BM packing biofilms (43) are provided and distributed between the second water distribution pipe (42) and the porous structure layer (44).

2. The printing and dyeing wastewater treatment system based on coupling of sulfur autotrophic denitrification and biofilm according to claim 1, characterized in that: It also includes a pretreatment unit (1) located at the end of the aerobic treatment unit (2) away from the anaerobic treatment unit (4). The pretreatment unit (1) includes an equalization tank (11). A vertically arranged grid plate (12) is fixed inside the equalization tank (11). The grid plate (12) has a number of evenly distributed through holes (13).

3. The printing and dyeing wastewater treatment system based on coupling of sulfur autotrophic denitrification and biofilm according to claim 2, characterized in that: The pretreatment unit (1) also includes a lift pump (14), which is fixed at one end of the equalization tank (11) near the aerobic tank (21). The equalization tank (11) is connected to the aerobic tank (21) through the lift pump (14).

4. The system for treatment of dyeing wastewater based on coupling of sulfur autotrophic denitrification and biofilm according to claim 1, characterized in that: The aerobic treatment unit (2) further includes a first screw pump (27), which is installed at one end of the aerobic tank (21) near the sedimentation tank (31) and is connected to the sedimentation tank (31).

5. The system for treatment of dyeing wastewater based on coupling of sulfur autotrophic denitrification and biofilm according to claim 1, characterized in that: The intermediate sedimentation unit (3) further includes a second screw pump (34) and a third screw pump (35). The second screw pump (34) is installed on the lower end face of the sedimentation tank (31), and the end of the second screw pump (34) away from the sedimentation tank (31) is connected to the aerobic tank (21). The third screw pump (35) is installed on the end of the sedimentation tank (31) near the anaerobic tank (41), and the third screw pump (35) is connected to the anaerobic tank (41).

6. The system for treatment of dyeing wastewater based on coupling of sulfur autotrophic denitrification and biofilm according to claim 1, characterized in that: The BF packing biofilm (26) is spherical, and the BM packing biofilm (43) is disc-shaped.

7. The system for treatment of dyeing wastewater based on coupling of sulfur autotrophic denitrification and biofilm according to claim 1, characterized in that it comprises: The anaerobic treatment unit (4) also includes a gas-liquid separation device (45), which is fixed to the top of the anaerobic tank (41).

Images