Wastewater treatment system and process based on anaerobic digestion and biological contact oxidation

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a wastewater treatment system and process based on anaerobic digestion and biological contact oxidation, the wastewater treatment system comprises a pretreatment unit, a biological treatment unit, a precipitation separation unit, a sludge treatment unit and an auxiliary equipment unit, and all the units work cooperatively. Pollutants in the waste water can be effectively removed, and the environment-friendly emission standard or the recycled water quality requirement is met; the system effectively intercepts impurities and regulates water quality through pretreatment units such as the grating channel and the primary sedimentation tank; anaerobic treatment, anoxic treatment and aerobic treatment are combined, organic matters are efficiently degraded, and pollutants are removed; water quality is clarified through the sedimentation tank to ensure that effluent stably reaches the standard; the sludge treatment unit effectively collects and treats sludge, and the treatment difficulty is reduced; a quartz sand filtering and PAM and PAC adding system is utilized, so that the treatment effect is further improved, and the effluent quality is ensured; meanwhile, the process is efficient in treatment, proper in sludge treatment and excellent in effluent quality.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a wastewater treatment system and process based on anaerobic digestion and biological contact oxidation. Background Art

[0002] According to the search, the invention patent with the application date of 2021-02-20 and the application number of CN202110193237.6 discloses a sewage treatment system, including an anaerobic tank, an anoxic tank, an aerobic tank and a sedimentation tank connected in sequence; a first return channel, the first return channel connects the anoxic tank and the anaerobic tank; a second return channel, the second return channel connects the anoxic tank and the aerobic tank; a third return channel, the third return channel connects the sedimentation tank and the anoxic tank; This sewage treatment system improves the ability of nitrogen removal and phosphorus removal in sewage treatment, but there are still some shortcomings: although the system improves the ability of nitrogen removal and phosphorus removal, it does not treat and dispose of the generated sludge, which contains a large amount of harmful substances such as organic matter, microorganisms and heavy metals. If not handled properly, it may cause secondary pollution to the environment; secondly, for sewage containing complex organic matter, the system cannot fully and effectively treat it, and the removal of pollutants in the sewage is not thorough; finally, the system has high energy consumption and the wastewater is not recycled, and the operating cost is high; therefore, a new type of wastewater treatment system and process is urgently needed to solve the above technical problems. Summary of the invention

[0003] In order to solve some of the problems existing in the above-mentioned prior art, the present invention provides a wastewater treatment system and process based on anaerobic digestion and biological contact oxidation.

[0004] To achieve the above-mentioned purpose, the present invention provides a wastewater treatment system based on anaerobic digestion and biological contact oxidation, wherein the wastewater treatment system comprises a pretreatment unit, a biological treatment unit, a sedimentation and separation unit, a sludge treatment unit and an auxiliary equipment unit, and through the coordinated work of each unit, pollutants in the wastewater can be effectively removed to meet environmental emission standards or recycled water quality requirements.

[0005] As a further improvement of the present invention, in order to enhance the filtering capacity, improve the conveying efficiency, and provide a stable influent water quality for subsequent treatment; the pretreatment unit includes a screen channel, a primary sedimentation tank, a water collection well and a regulating tank, and the screen channel, the primary sedimentation tank, the water collection well and the regulating tank are connected in sequence; the screen channel is arranged at the inlet end of the wastewater treatment system, and a screen is arranged in the screen channel, and the large particles of solid impurities in the wastewater are intercepted by the screen; a dark rod circular gate is also arranged in the screen channel, and the wastewater flow is adjusted by the dark rod circular gate to prevent wastewater from overflowing; a hydraulic screen is arranged in the primary sedimentation tank, and the hydraulic screen is used to further intercept finer suspended matter in the wastewater; a screw pump is also arranged between the screen channel and the primary sedimentation tank, and the wastewater is transported from the screen channel to the primary sedimentation tank by the screw pump; a water collection well lifting pump is arranged in the water collection well, and the wastewater treated in the primary sedimentation tank is collected by the water collection well lifting pump; a regulating tank agitator is arranged in the regulating tank, and the wastewater is stirred by the regulating tank agitator to make the wastewater mixed evenly.

[0006] As a further improvement of the present invention, in order to increase the contact area and contact time between wastewater and microorganisms, and improve the decomposition efficiency and wastewater treatment quality; the biological treatment unit includes anaerobic treatment, anoxic treatment and aerobic treatment, the anaerobic treatment includes an ABR tank, the ABR tank adopts a baffle structure, and uses anaerobic microorganisms to decompose organic matter in the wastewater under anaerobic conditions; the anoxic treatment includes an anoxic tank, an anoxic tank mixer is provided in the anoxic tank, and the wastewater is stirred by the anoxic tank mixer, so that the wastewater is fully in contact with the microorganisms, and the organic matter is further degraded in an anaerobic environment to remove impurities; the aerobic treatment includes a primary contact oxidation tank and a secondary contact oxidation tank, and by utilizing aerobic microorganisms on the biofilm, pollutants such as ammonia nitrogen and phosphorus in the wastewater can be efficiently removed.

[0007] As a further improvement of the present invention, in order to effectively remove suspended matter in wastewater and improve the sedimentation effect and water reuse; the sedimentation separation unit includes a middle sedimentation tank and a sedimentation tank, and the suspended matter in the effluent from the primary contact oxidation tank and the secondary contact oxidation tank is precipitated through the middle sedimentation tank and the sedimentation tank respectively to clarify the water quality; the sedimentation separation unit also includes an intermediate tank and a clear water tank, and the intermediate tank and the clear water tank are connected; the effluent from the intermediate tank enters the clear water tank, and the effluent from the clear water tank can be discharged or reused after meeting the standards.

[0008] As a further improvement of the present invention, in order to optimize the collection and transportation of sludge and avoid the residue and accumulation of sludge in the system; the sludge treatment unit includes a sludge tank, and the sludge generated during the treatment process is collected through the sludge tank; a sludge tank discharge pump is provided in the sludge tank, and the collected sludge is discharged through the sludge tank discharge pump; a sedimentation tank sludge pump is provided in the primary sedimentation tank, and the sludge in the sedimentation tank is transported to the sludge tank through the sedimentation tank sludge pump; the sludge treatment unit also includes a filter press room that is arranged in conjunction with it, and a belt filter press is provided in the filter press room, and the sludge is filtered through the belt filter press to reduce the volume and facilitate disposal.

[0009] As a further improvement of the present invention, in order to strengthen the oxygen supply method and improve the oxidation and decomposition efficiency of organic matter and the filtering effect of clean water; the auxiliary equipment unit includes a filter room, which is equipped with a quartz sand filter, and the clean water can be further filtered through the quartz sand filter; the filter room is also equipped with a backwash pump and a pressure pump; the auxiliary equipment unit also includes a blower room, in which a number of blowers are installed, and the blowers are used to provide oxygen to the primary contact oxidation tank and the secondary contact oxidation tank to further oxidize and decompose organic matter.

[0010] As a further improvement of the present invention, in order to realize the recycling of wastewater, the nutrients in the wastewater can participate in the biological treatment process again to improve the utilization rate of resources; a reflux pump is arranged between the anoxic tank and the sedimentation tank, and part of the effluent from the sedimentation tank is returned to the anoxic tank through the reflux pump to realize the recycling of wastewater.

[0011] As a further improvement of the present invention, in order to improve the dewatering performance of the sludge, reduce the moisture content in the sludge, and improve the efficiency and quality of sludge treatment; an acid-base neutralization device is also arranged in front of the belt filter press, and the pH value of the sludge is adjusted by the acid-base neutralization device to improve the dewatering effect.

[0012] As a further improvement of the present invention, in order to improve the coagulation and sedimentation effects of suspended matter and colloidal particles in the wastewater and to facilitate the control and management of the entire filtration process; a PAM dosing system and a PAC dosing system are also provided in the filter room, and polyacrylamide (PAM) and polyaluminium chloride (PAC) are respectively added into the system through the PAM dosing system and the PAC dosing system as coagulants to improve the coagulation and sedimentation effects of suspended matter and colloidal particles in the wastewater; a control cabinet is also provided in the filter room.

[0013] One of the beneficial effects of the present invention is that: by connecting the grid channel, the primary sedimentation tank, the water collection well and the regulating tank in sequence, the large solid impurities and suspended matter in the wastewater are effectively intercepted, the wastewater flow is adjusted, and stable water quality conditions are provided for subsequent treatment; by adopting a combination of anaerobic treatment, anoxic treatment and aerobic treatment, the synergistic effect of anaerobic microorganisms, anoxic environment and aerobic microorganisms is utilized to efficiently degrade organic matter in the wastewater, remove pollutants such as ammonia nitrogen and phosphorus, and improve the wastewater treatment effect; the suspended matter in the effluent after biological treatment is precipitated by the intermediate sedimentation tank and the sedimentation tank, and the water quality is further clarified; at the same time, the connection design of the intermediate tank and the clear water tank ensures the stability of the effluent water quality and the possibility of meeting the discharge standards or reuse; through the cooperation of the sludge tank, the filter press room and other equipment, the sludge generated in the treatment process is effectively collected and treated, and the volume of the sludge and the difficulty of disposal are reduced; in addition, the wastewater treatment effect and effluent water quality are further improved by the setting of the quartz sand filter, the PAM dosing system and the PAC dosing system.

[0014] The present invention provides a wastewater treatment process based on anaerobic digestion and biological contact oxidation, the wastewater treatment process comprising the following steps: Step 1: The wastewater first enters the screen channel for preliminary filtration, and the screen intercepts large solid impurities and suspended matter; Step 2: The wastewater after treatment in the screen channel flows into the primary sedimentation tank and is further removed from suspended solids and settleable matter through a hydraulic screen; Step 3: The wastewater is then transported to the water collection well through a pipeline, lifted to the regulating tank by the water collection well lifting pump, and mixed evenly by the regulating tank mixer to ensure the stability of the subsequent treatment process; Step 4: The effluent from the regulating tank flows into the ABR tank through a pipeline, where it undergoes anaerobic digestion treatment, using anaerobic microorganisms to decompose organic matter in the wastewater into small molecules; Step 5: The wastewater after anaerobic treatment enters the anoxic tank and is stirred by the anoxic tank mixer to allow the wastewater to fully contact with microorganisms and degrade organic matter in an anaerobic environment; Step 6: The wastewater after anoxic treatment enters the primary contact oxidation tank and the secondary contact oxidation tank in turn, and the aerobic microorganisms attached to the filler are used to further degrade the organic matter in the wastewater; Step 7: The wastewater after aerobic treatment enters the intermediate sedimentation tank and sedimentation tank for sedimentation, removes suspended matter and clarifies the water quality; the settled water enters the intermediate tank and then the clear water tank, and is discharged or reused after meeting the standards; Step 8: The sludge generated during the treatment process is collected in the sludge pool and discharged through the sludge pool sludge pump; the sludge is further filtered through a belt filter press in the filter press room to reduce the volume; before filtering, the sludge is adjusted to pH value through an acid-base neutralization device to improve the dehydration effect; Step 9: The water in the clear water tank can be further filtered through the quartz sand filter in the filter room; at the same time, polyacrylamide (PAM) and polyaluminium chloride (PAC) are added to the system through the PAM dosing system and the PAC dosing system to improve the coagulation and sedimentation effect of suspended matter and colloidal particles; the blower in the blower room provides oxygen for the primary contact oxidation tank and the secondary contact oxidation tank; Step 10: Part of the effluent from the sedimentation tank can be returned to the anoxic tank through a reflux pump to achieve the recycling of wastewater.

[0015] Another beneficial effect of the present invention is that through carefully designed operating steps, the treatment effect is improved, the stability of effluent water quality is improved, and the comprehensive and efficient removal of pollutants in wastewater is achieved. It is an efficient and environmentally friendly wastewater treatment process with broad application prospects.

[0016] When the present invention is working, the wastewater first enters the screen channel, and after the large particles of solid impurities are intercepted by the screen, the flow is adjusted by the concealed rod round gate to prevent overflow; then, the wastewater is transported to the primary sedimentation tank by the screw pump, and the hydraulic screen further removes the suspended matter; then, the wastewater enters the water collection well, and is lifted to the regulating tank by the water collection well lifting pump, and the regulating tank mixer ensures that the water quality is evenly mixed; then, the wastewater flows into the ABR tank for anaerobic digestion and decomposes into small molecular substances; then, it enters the anoxic tank to further degrade organic matter in anoxic environment; then it enters the primary contact oxidation tank and the secondary contact oxidation tank in sequence, and aerobic microorganisms are used to degrade organic matter; The treated wastewater passes through the intermediate settling tank and sedimentation tank to remove suspended solids, clarify the water quality, and enter the intermediate tank and clear water tank. It is discharged or reused after meeting the standards. At the same time, the sludge is collected in the sludge tank, discharged through the sludge tank sludge pump, and filtered by a belt filter press in the filter press room. The acid-base neutralization equipment adjusts the pH value to improve the dehydration effect. The water in the clear water tank can be further filtered through a quartz sand filter. The PAM dosing system and the PAC dosing system improve the coagulation effect of suspended solids. The blower in the blower room provides oxygen for aerobic treatment. Finally, part of the effluent from the sedimentation tank is returned to the anoxic tank through a reflux pump for recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to facilitate the understanding of those skilled in the art, the present invention is further described below with reference to the accompanying drawings: Figure 1 Schematic diagram of the wastewater treatment system of the present invention Figure 1 .

[0018] Figure 2 Schematic diagram of the wastewater treatment system of the present invention Figure 2 .

[0019] Figure 3 It is a schematic diagram of the wastewater treatment process of the present invention.

[0020] Among them, 1 screen channel, 2 primary sedimentation tank, 3 water collection well, 4 regulating tank, 5ABR tank, 6 anoxic tank, 7 primary contact oxidation tank, 8 middle sedimentation tank, 9 secondary contact oxidation tank, 10 sedimentation tank, 11 intermediate tank, 12 clear water tank, 13 sludge tank, 14 filter room, 15 blower room, 16 filter press room, 17 sludge tank sludge pump, 18 concealed rod round gate, 19 reflux pump, 20 sedimentation tank sludge pump, 21 anoxic tank mixer, 22 screen, 23 hydraulic screen, 24 screw pump, 25 water collection well lifting pump, 26 regulating tank mixer, 27 blower, 28 belt filter press, 29 acid-base neutralization equipment, 30 control cabinet, 31 backwash pump, 32 pressure pump, 33 quartz sand filter, 34PAM dosing system, 35PAC dosing system. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solution in this application, Figure 1-3 The present invention is further described. The following examples are only used to more clearly illustrate the technical solution of the present invention, and are not intended to limit the protection scope of the present invention.

[0022] like Figure 1-2A wastewater treatment system based on anaerobic digestion and biological contact oxidation is shown, characterized in that the wastewater treatment system includes a pretreatment unit, a biological treatment unit, a sedimentation and separation unit, a sludge treatment unit and an auxiliary equipment unit, and the units work together to effectively remove pollutants in the wastewater to meet environmental emission standards or recycled water quality requirements; the pretreatment unit includes a grid channel 1, a primary sedimentation tank 2, a water collection well 3 and a regulating tank 4, and the grid channel 1, the primary sedimentation tank 2, the water collection well 3 and the regulating tank 4 are connected in sequence; the grid channel 1 is arranged at the inlet end of the wastewater treatment system, and a grid 22 is arranged in the grid channel 1, and large particles of solid impurities in the wastewater are intercepted by the grid 22; the grid channel 1 also has A concealed circular gate 18 is provided, and the wastewater flow is adjusted by the concealed circular gate 18 to prevent wastewater from overflowing; a hydraulic screen 23 is provided in the primary sedimentation tank 2, and the hydraulic screen 23 further intercepts finer suspended matter in the wastewater; a screw pump 24 is also provided between the grid channel 1 and the primary sedimentation tank 2, and the wastewater is transported from the grid channel 1 to the primary sedimentation tank 2 through the screw pump 24; a water collection well lifting pump 25 is provided in the water collection well 3, and the wastewater treated in the primary sedimentation tank 2 is collected by the water collection well lifting pump 25; a regulating tank mixer 26 is provided in the regulating tank 4, and the wastewater is stirred by the regulating tank mixer 26 to make the wastewater mixed evenly; the biological treatment unit includes anaerobic treatment, anoxic treatment and aerobic treatment The anaerobic treatment includes an ABR tank 5, which adopts a baffle structure and uses anaerobic microorganisms to decompose organic matter in the wastewater under anaerobic conditions; the anoxic treatment includes an anoxic tank 6, which is provided with an anoxic tank mixer 21, and the wastewater is stirred by the anoxic tank mixer 21, so that the wastewater is fully contacted with the microorganisms, and the organic matter is further degraded in an anaerobic environment to remove impurities; the aerobic treatment includes a primary contact oxidation tank 7 and a secondary contact oxidation tank 9, and by using aerobic microorganisms on the biofilm, pollutants such as ammonia nitrogen and phosphorus in the wastewater can be efficiently removed; the sedimentation separation unit includes a middle sedimentation tank 8 and a sedimentation tank 10, and the first contact oxidation tank is respectively contacted with the middle sedimentation tank 8 and the sedimentation tank 10. The suspended matter in the effluent of the contact oxidation tank 7 and the secondary contact oxidation tank 9 is precipitated to clarify the water quality; the sedimentation and separation unit also includes an intermediate tank 11 and a clear water tank 12, and the intermediate tank 11 and the clear water tank 12 are connected; the effluent of the intermediate tank 11 enters the clear water tank 12, and the effluent of the clear water tank 12 can be discharged or reused after reaching the standard; the sludge treatment unit includes a sludge tank 13, and the sludge generated during the treatment process is collected by the sludge tank 13; a sludge tank sludge pump 17 is provided in the sludge tank 13, and the collected sludge is discharged by the sludge tank sludge pump 17; a sedimentation tank sludge pump 20 is provided in the primary sedimentation tank 2, and the sludge in the sedimentation tank 10 is transported to the sludge tank 13 by the sedimentation tank sludge pump 20;The sludge treatment unit also includes a filter press room 16, in which a belt filter press 28 is provided, and the sludge is filtered by the belt filter press 28 to reduce the volume and facilitate disposal; the auxiliary equipment unit includes a filter room 14, in which a quartz sand filter 33 is provided, and the clean water can be further filtered by the quartz sand filter 33; the filter room 14 is also provided with a backwash pump 31 and a booster pump 32; the auxiliary equipment unit also includes a blower room 15, in which a plurality of blowers 27 are installed, and oxygen is provided to the primary contact oxidation tank 7 and the secondary contact oxidation tank 9 by the blowers 27 to further oxidize and decompose organic matter; A reflux pump 19 is provided between the anoxic tank 6 and the sedimentation tank 10, and part of the effluent from the sedimentation tank 10 is refluxed to the anoxic tank 6 through the reflux pump 19, so as to realize the recycling of wastewater; an acid-base neutralization device 29 is also provided in front of the belt filter press 28, and the pH value of the sludge is adjusted through the acid-base neutralization device 29 to improve the dehydration effect; a PAM dosing system 34 and a PAC dosing system 35 are also provided in the filter room 14, and polyacrylamide (PAM) and polyaluminium chloride (PAC) are respectively added to the system through the PAM dosing system 34 and the PAC dosing system 35 as coagulants to improve the coagulation and sedimentation effect of suspended matter and colloidal particles in the wastewater; a control cabinet 30 is also provided in the filter room 14. ;

[0023] like Figure 3 A wastewater treatment process based on anaerobic digestion and biological contact oxidation is shown, and the wastewater treatment process comprises the following steps: Step 1: The wastewater first enters the screen channel 1 for preliminary filtration, and the large particles of solid impurities and suspended matter are intercepted by the screen 22; Step 2: The wastewater treated by the screen channel 1 flows into the primary sedimentation tank 2 and further removes suspended solids and precipitable substances through the hydraulic screen 23; Step 3: The wastewater is then transported to the water collection well 3 through a pipeline, lifted to the regulating tank 4 by the water collection well lifting pump 25, and mixed evenly by the regulating tank mixer 26 to ensure the stability of the subsequent treatment process; Step 4: The effluent from the regulating tank 4 flows into the ABR tank 5 through a pipeline, and is subjected to anaerobic digestion treatment in the ABR tank 5, where anaerobic microorganisms are used to decompose organic matter in the wastewater into small molecules; Step 5: The wastewater after anaerobic treatment enters the anoxic tank 6 and is stirred by the anoxic tank mixer 21 to allow the wastewater to fully contact with the microorganisms and degrade organic matter in an anaerobic environment; Step 6: The wastewater after anoxic treatment enters the primary contact oxidation tank 7 and the secondary contact oxidation tank 9 in sequence, and the aerobic microorganisms attached to the fillers are used to further degrade organic matter in the wastewater; Step 7: The wastewater after aerobic treatment enters the intermediate sedimentation tank 8 and the sedimentation tank 10 for sedimentation, removing suspended matter and clarifying the water quality; the precipitated water enters the intermediate tank 11 and then enters the clear water tank 12, and is discharged or reused after meeting the standards; Step 8: The sludge generated during the treatment process is collected in the sludge pool 13 and discharged through the sludge pool sludge pump 17; the sludge is further filtered through the belt filter press 28 in the filter press room 16 to reduce the volume; before filtering, the sludge is adjusted to pH value through the acid-base neutralization device 29 to improve the dehydration effect; Step nine: The water in the clean water tank 12 can be further filtered through the quartz sand filter 33 in the filter room 14; at the same time, polyacrylamide PAM and polyaluminium chloride PAC are added to the system through the PAM dosing system 34 and the PAC dosing system 35 to improve the coagulation and sedimentation effect of suspended matter and colloidal particles; the blower 27 in the blower room 15 provides oxygen for the primary contact oxidation tank 7 and the secondary contact oxidation tank 9; Step 10: Part of the effluent from the sedimentation tank 10 can be returned to the anoxic tank 6 through the reflux pump 19 to achieve recycling of wastewater.

[0024] When the present invention is working, the wastewater first enters the screen channel 1, and after the large particles of solid impurities are intercepted by the screen 22, the flow is adjusted by the concealed rod round gate 18 to prevent overflow; then, the wastewater is transported to the primary sedimentation tank 2 by the screw pump 24, and the hydraulic screen 23 further removes the suspended matter; then, the wastewater enters the water collection well 3, and is lifted to the regulating tank 4 by the water collection well lifting pump 25, and the regulating tank mixer 26 ensures that the water quality is evenly mixed; then, the wastewater flows into the ABR tank 5 for anaerobic digestion and decomposes into small molecular substances; then, it enters the anoxic tank 6 to further degrade organic matter in anoxic environment; then it enters the primary contact oxidation tank 7 and the secondary contact oxidation tank 9 in sequence, and aerobic microorganisms are used to degrade organic matter; the treated wastewater passes After passing through the intermediate sedimentation tank 8 and the sedimentation tank 10, the suspended solids are removed, the water quality is clarified, and then the water enters the intermediate tank 11 and the clear water tank 12, and is discharged or reused after meeting the standards; at the same time, the sludge is collected in the sludge tank 13, discharged through the sludge tank sludge pump 17, and filtered by the belt filter press 28 in the filter press room 16, and the acid-base neutralization equipment 29 adjusts the pH value to improve the dehydration effect; the water in the clear water tank 12 can also be further filtered by the quartz sand filter 33, and the PAM dosing system 34 and the PAC dosing system 35 improve the coagulation effect of suspended solids; the blower 27 in the blower room 15 provides oxygen for aerobic treatment; finally, part of the effluent from the sedimentation tank 10 is returned to the anoxic tank 6 through the reflux pump 19 to achieve recycling.

[0025] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A wastewater treatment system based on anaerobic digestion and biological contact oxidation, characterized in that: The wastewater treatment system includes a pretreatment unit, a biological treatment unit, a sedimentation and separation unit, a sludge treatment unit and an auxiliary equipment unit, and the units work together to effectively remove pollutants in the wastewater to meet environmental emission standards or recycled water quality requirements.

2. A wastewater treatment system based on anaerobic digestion and biological contact oxidation according to claim 1, characterized in that: The pretreatment unit comprises a screen channel (1), a primary sedimentation tank (2), a water collection well (3) and a regulating tank (4), wherein the screen channel (1), the primary sedimentation tank (2), the water collection well (3) and the regulating tank (4) are connected in sequence; the screen channel (1) is arranged at the inlet end of the wastewater treatment system, a screen (22) is arranged in the screen channel (1), and large solid impurities in the wastewater are intercepted by the screen (22); a concealed rod circular gate (18) is also arranged in the screen channel (1), and the wastewater flow is adjusted by the concealed rod circular gate (18) to prevent wastewater from overflowing; a water collection well (22) is arranged in the primary sedimentation tank (2) A hydraulic screen (23) is provided in the water collecting well (3), and finer suspended matter in the wastewater is further intercepted by the hydraulic screen (23); a screw pump (24) is also provided between the screen channel (1) and the primary sedimentation tank (2), and the wastewater is transported from the screen channel (1) to the primary sedimentation tank (2) by the screw pump (24); a water collecting well lifting pump (25) is provided in the water collecting well (3), and the wastewater treated in the primary sedimentation tank (2) is collected by the water collecting well lifting pump (25); a regulating tank agitator (26) is provided in the regulating tank (4), and the wastewater is stirred by the regulating tank agitator (26) to make the wastewater evenly mixed.

3. A wastewater treatment system based on anaerobic digestion and biological contact oxidation according to claim 1, characterized in that: The biological treatment unit comprises anaerobic treatment, anoxic treatment and aerobic treatment. The anaerobic treatment comprises an ABR tank (5). The ABR tank (5) adopts a baffle structure and utilizes anaerobic microorganisms to decompose organic matter in the wastewater under anaerobic conditions. The anoxic treatment comprises an anoxic tank (6). An anoxic tank agitator (21) is provided in the anoxic tank (6). The wastewater is agitated by the anoxic tank agitator (21) so that the wastewater is fully in contact with the microorganisms, and the organic matter is further degraded in the anoxic environment to remove impurities. The aerobic treatment comprises a primary contact oxidation tank (7) and a secondary contact oxidation tank (9). By utilizing aerobic microorganisms on the biofilm, pollutants such as ammonia nitrogen and phosphorus in the wastewater can be efficiently removed.

4. A wastewater treatment system based on anaerobic digestion and biological contact oxidation according to claim 1, characterized in that: The sedimentation separation unit comprises a middle sedimentation tank (8) and a sedimentation tank (10), and the suspended matter in the effluent of the primary contact oxidation tank (7) and the secondary contact oxidation tank (9) is precipitated through the middle sedimentation tank (8) and the sedimentation tank (10) respectively to clarify the water quality; the sedimentation separation unit also comprises an intermediate tank (11) and a clear water tank (12), and the intermediate tank (11) and the clear water tank (12) are connected; the effluent of the intermediate tank (11) enters the clear water tank (12), and the effluent of the clear water tank (12) can be discharged or reused after meeting the standards.

5. A wastewater treatment system based on anaerobic digestion and biological contact oxidation according to claims 1 and 2, characterized in that: The sludge treatment unit comprises a sludge pool (13), and sludge generated during the treatment process is collected through the sludge pool (13); a sludge pool sludge pump (17) is provided in the sludge pool (13), and the collected sludge is discharged through the sludge pool sludge pump (17); a sedimentation tank sludge pump (20) is provided in the primary sedimentation tank (2), and the sludge in the sedimentation tank (10) is transported to the sludge pool (13) through the sedimentation tank sludge pump (20); the sludge treatment unit also comprises a filter press room (16) provided in conjunction with the filter press room (16), a belt filter press (28) is provided in the filter press room (16), and the sludge is subjected to filter pressing treatment through the belt filter press (28), thereby reducing the volume and facilitating disposal.

6. A wastewater treatment system based on anaerobic digestion and biological contact oxidation according to claims 1 and 3, characterized in that: The auxiliary equipment unit comprises a filter room (14), in which a quartz sand filter (33) is arranged, and the clean water can be further filtered through the quartz sand filter (33); the filter room (14) is also provided with a backwash pump (31) and a pressure pump (32); the auxiliary equipment unit also comprises a blower room (15), in which a plurality of blowers (27) are installed, and oxygen is provided to the primary contact oxidation tank (7) and the secondary contact oxidation tank (9) through the blowers (27), so as to further oxidize and decompose organic matter.

7. A wastewater treatment system based on anaerobic digestion and biological contact oxidation according to claims 3 and 4, characterized in that: A reflux pump (19) is provided between the anoxic tank (6) and the sedimentation tank (10), and a portion of the effluent from the sedimentation tank (10) is refluxed to the anoxic tank (6) via the reflux pump (19), thereby realizing the recycling of wastewater.

8. A wastewater treatment system based on anaerobic digestion and biological contact oxidation according to claim 5, characterized in that: An acid-base neutralization device (29) is also provided in front of the belt filter press (28), and the pH value of the sludge is adjusted by the acid-base neutralization device (29) to improve the dehydration effect.

9. A wastewater treatment system based on anaerobic digestion and biological contact oxidation according to claim 6, characterized in that: The filter room (14) is also provided with a PAM dosing system (34) and a PAC dosing system (35), and polyacrylamide (PAM) and polyaluminium chloride (PAC) are respectively added into the system as coagulants through the PAM dosing system (34) and the PAC dosing system (35), so as to improve the coagulation and sedimentation effects of suspended matter and colloidal particles in the wastewater; the filter room (14) is also provided with a control cabinet (30).

10. A wastewater treatment process based on anaerobic digestion and biological contact oxidation, characterized in that: The wastewater treatment process comprises the following steps: Step 1: The wastewater first enters the screen channel (1) for preliminary filtration, and large particles of solid impurities and suspended matter are intercepted by the screen (22); Step 2: The wastewater treated by the screen channel (1) flows into the primary sedimentation tank (2) and passes through the hydraulic screen (23) to further remove suspended matter and precipitable matter; Step 3: The wastewater is then transported to the water collection well (3) through a pipeline, lifted to the regulating tank (4) by the water collection well lifting pump (25), and mixed evenly by the regulating tank mixer (26) to ensure the stability of the subsequent treatment process; Step 4: The effluent from the regulating tank (4) flows into the ABR tank (5) through a pipeline, and is subjected to anaerobic digestion treatment in the ABR tank (5), where anaerobic microorganisms are used to decompose organic matter in the wastewater into small molecules; Step 5: The wastewater after anaerobic treatment enters the anoxic tank (6) and is stirred by the anoxic tank mixer (21) so that the wastewater is fully in contact with the microorganisms and organic matter is degraded in the anoxic environment; Step 6: The wastewater after anoxic treatment enters the primary contact oxidation tank (7) and the secondary contact oxidation tank (9) in sequence, and the aerobic microorganisms attached to the filler are used to further degrade organic matter in the wastewater; Step 7: The wastewater after aerobic treatment enters the intermediate sedimentation tank (8) and the sedimentation tank (10) for sedimentation to remove suspended matter and clarify the water quality; the precipitated water enters the intermediate tank (11) and then enters the clear water tank (12), and is discharged or reused after meeting the standards; Step 8: The sludge generated during the treatment process is collected in a sludge pool (13) and discharged through a sludge pool discharge pump (17); the sludge is further filtered through a belt filter press (28) in a filter press room (16) to reduce the volume; before filtering, the sludge is adjusted in pH value through an acid-base neutralization device (29) to improve the dehydration effect; Step 9: The water in the clear water tank (12) can be further filtered through the quartz sand filter (33) in the filter room (14); at the same time, polyacrylamide (PAM) and polyaluminium chloride (PAC) are added to the system through the PAM dosing system (34) and the PAC dosing system (35) to improve the coagulation and sedimentation effect of suspended matter and colloidal particles; the blower (27) in the blower room (15) provides oxygen to the primary contact oxidation tank (7) and the secondary contact oxidation tank (9); Step 10: Part of the effluent from the sedimentation tank (10) can be returned to the anoxic tank (6) through a reflux pump (19) to achieve recycling of wastewater.

Images