CN106746352A - A kind of development zone composite waste processing system - Google Patents

Abstract

The invention relates to a mixed wastewater treatment system in a development zone, which includes a wastewater regulating tank, an anaerobic reaction tank, a multi-stage biochemical tank, an aerobic contact oxidation tank and a sand filter tank; Sludge area, mixing area and separation area, the separation area includes the catchment area and the slag collection area located in the catchment area; the multi-stage biochemical pool includes the anoxic section and the aerobic section separated by glass plates and baffles; The aerobic contact oxidation tank is equipped with a water inlet pipe, a water distribution triangle, a membrane module and an aeration control system; the wastewater is adjusted by the adjustment tank to adjust the water volume and water quality, and then enters the anaerobic reaction tank to provide organic carbon sources for the dilution process of phosphorus-accumulating bacteria, and then Wastewater enters multi-stage biochemical pools and aerobic contact oxidation pools for anoxic and aerobic reactions, and is discharged up to standard after sedimentation and filtration.

Description

A mixed wastewater treatment system for a development zone

technical field

The invention relates to the technical field of wastewater treatment, in particular to a mixed wastewater treatment system in a development zone.

Background technique

The mixed wastewater in the development zone is mainly from the chemical industry, and the wastewater is mainly industrial wastewater discharged from the production process of dyes, pharmaceuticals, pesticide intermediates and other fine chemical products. The water quality is extremely complex, with deep color and high acidity. The content of organic and toxic substances is high .

It is difficult to meet the requirements of high efficiency, energy saving, low cost and environmental protection by using traditional physical, chemical and biochemical treatment processes to treat mixed wastewater in the development zone. Therefore, based on traditional physical, chemical and biochemical treatment processes, an improved or innovative new combination The research and development of the process has become a hot spot in the research of mixed wastewater treatment in the development zone.

Contents of the invention

The technical problem to be solved by the present invention is: in order to solve the above-mentioned difficult problems in the treatment of mixed wastewater in the development zone, the invention provides a mixed wastewater treatment system in the development zone.

The technical solution adopted by the present invention to solve its technical problems is: a mixed wastewater treatment system in a development zone, including a wastewater regulating tank, anaerobic reaction tank, multi-stage biochemical tank, aerobic contact oxidation tank and sand filter; The regulating tank, the anaerobic reaction tank, the multi-stage biochemical tank, the aerobic contact oxidation tank and the sand filter tank are connected in sequence.

The wastewater regulating pool includes a water inlet pipe and a water outlet pipe for regulating the water quality and water quantity of the mixed wastewater in the development zone.

The anaerobic reaction tank includes a water inlet pipe and an outlet pipe for discharging treated water, and the anaerobic reaction tank is sequentially composed of a sand collection area, a sludge area, a mixing area and a separation area from bottom to top; The separation area includes a water collection area and a slag collection area located in the water collection area; a stirring device is provided between the sludge area and the mixing area of the anaerobic reaction tank, and a water distribution branch pipe is provided above the stirring device. The water distribution branch pipe is connected to the water inlet pipe; a three-phase separator is provided in the separation area, and the three-phase separator includes a deflector and a triangular deflector ring located below the deflector and used in conjunction with the deflector , the triangular deflector ring is installed on the inner wall of the anaerobic reaction tank, the upper part of the deflector is in the same shape as the separation zone, the lower part of the deflector is trumpet-shaped, and the deflector is The inner diameter of the lower part of the plate is larger than the inner diameter of the triangular guide ring; the upper part of the outer wall of the separation area is provided with an overflow weir, and the overflow weir is connected with the outlet pipe; Groove; when the waste water overflows from bottom to top, water and scum enter the lower part of the deflector through the triangular diversion ring together, and the scum continues to enter the slag collection area upwards, and the water passes through the gap between the deflector and the triangular diversion ring. The gap enters the catchment area; in order to have a better effect on wastewater treatment, the water distribution branch pipe is set in a concentric circle shape or a cross shape, and the water distribution branch pipe has a horizontal radiation outlet; further, due to the different densities of water and sediment, Separation is realized under the action of a three-phase separator; in order to discharge the treated sediment, a sediment discharge valve is provided at the bottom of the anaerobic reaction tank.

The outlet pipe of the anaerobic reaction tank communicates with the water inlet pipe of the multi-stage biochemical tank.

The multi-stage biochemical pool includes an anaerobic reaction pool separated by a baffle plate, an aerobic reaction pool and an anoxic reaction pool, and the head end of the first-stage anaerobic reaction pool is provided with an inlet pipe for feeding waste water, The end of the first-stage aerobic reaction pool is connected with the head end of the first-stage anoxic reaction pool, and the end of the second-stage aerobic reaction pool is connected with the head end of the second-stage anoxic reaction pool; The lower part of the side baffles is provided with a 45-degree corner to avoid the impact of the water flow when it enters, so as to buffer the water flow and distribute water evenly; the end of the third-stage aerobic reaction tank is equipped with a three-phase separator and overflow water Weir, the overflow weir is connected to the outlet pipe; the first-level anaerobic reaction tank and the first-level aerobic reaction tank, the first-level anoxic reaction tank and the second-level aerobic reaction tank, the second-level anoxic reaction tank and The baffles with holes are used to isolate the third-stage aerobic reaction tanks. Aeration devices are arranged at the bottom of the aerobic reaction tanks. The bottom is designed as a conical structure, and the conical structure is connected to the sludge discharge valve; the multiple The upper cover of the first-stage anaerobic reaction pool, the first-stage anoxic reaction pool, and the second-stage anoxic reaction pool of the first-stage biochemical pool is designed as a conical structure, and the top of the conical structure is equipped with a methane exhaust gas collection pipe;

The lower part of the aerobic contact oxidation tank is provided with a water inlet pipe, and the lower part of the water inlet pipe is provided with a water distribution triangle cone; the lower part of the water distribution triangle cone is provided with an aeration control system, and the aeration control system includes an aeration plate, Blower and dissolved oxygen measurement and control device; further, the aeration pan is a microporous aeration pan with micropores evenly arranged; the aeration pan is connected to the blower through the aeration pipe, and the blower is set at Outside the pool, a dissolved oxygen measurement and control device is installed on the upper part of the aerobic contact oxidation tank and under the wastewater surface, and the dissolved oxygen measurement and control device regulates the work of the blower according to the oxygen capacity; the upper part of the water inlet pipe has a built-in membrane module; the aerobic contact An overflow weir is arranged at the outlet of the oxidation tank, and the treated water enters the sand filter tank.

A part of the sludge in the aerobic contact oxidation tank is returned to the anaerobic reaction tank through the sludge return pump for anaerobic phosphorus release, and a part is used as excess sludge. A method for wastewater treatment using the above-mentioned mixed wastewater treatment system in the development zone has the following steps:

①The mixed wastewater in the development zone enters the wastewater regulating tank through the water inlet pipe to adjust the water quality and water quantity;

② Then the sewage enters the middle and lower part of the separation zone of the anaerobic reaction tank through the water inlet pipe; the stirring device located under the water inlet pipe of the anaerobic reaction tank makes the solid matter in the sewage rub against and removes other pollutants on the solid matter; the floating water in the sewage The scum rises under the action of buoyancy, and rises to the slag collection area under the action of the three-phase separator in the anaerobic reaction tank. Under the action of the scum scraper, the scum enters the scum tank and is cleaned and transported; Under the action, it sinks to the sand collection area at the lower part of the anaerobic reaction tank, and is discharged through the sediment discharge valve at the bottom of the anaerobic reaction tank; the separated water enters the anaerobic reaction tank under the action of the deflector in the three-phase separation area of the anaerobic reaction tank. The water collection area of the reaction tank is connected to the water inlet pipe of the multi-stage biochemical tank through the overflow weir, the outlet pipe and the connecting pipe;

③ The inlet pipe (2-8) of the first-stage anaerobic reaction tank through which the waste water passes enters the lower part of the multi-stage biochemical pool (2); after entering the multi-stage biochemical pool, the waste water advances up and down along the baffle plate (2-1). The aeration discs (2-14) located below the aerobic zones at all levels generate a large number of fine air bubbles to further rub the solids in the sewage, and at the same time oxidize the macromolecular substances in the wastewater into small molecular substances that are easy to absorb and adsorb. The waste water passes through the sludge bed of each reaction tank in the multi-stage biochemical tank in turn. The sludge in the reaction tank moves with the up and down flow of the waste water and the rise of biogas. The blocking effect of the baffle (2-1) and the sewage The sedimentation of the mud itself reduces the flow rate of the sludge, so a large amount of sludge is trapped in the reaction tank, and the microorganisms in the reaction tank fully contact with the organic matter in the wastewater; the heterotrophic bacteria in the multi-stage biochemical tank convert the wastewater Suspended pollutants such as starch, fiber, carbohydrates and soluble organic matter in the water are hydrolyzed into organic acids, so that the macromolecular organic matter is decomposed into small molecular organic matter, and the insoluble organic matter is converted into soluble organic matter;

④Through the waste water after the multi-stage biochemical tank reaction, the three-phase separator (2-9) provided at the end of the third-stage aerobic reaction tank (2-7) realizes the separation of mud, water and methane gas, and the sludge is separated by gravity. sinks to the lower part of the multi-stage biochemical tank, and the excess sludge is discharged through the sludge discharge valve (2-11) at the bottom; the methane waste gas generated by the multi-stage biochemical tank passes through the gas collecting pipe (2-13) at the top of the reaction tank Collect and discharge; the waste water is connected to the inlet pipe of the aerobic contact oxidation tank (3) through the overflow weir, the outlet pipe and the connecting pipe;

⑤Wastewater enters the middle and lower part of the aerobic contact oxidation tank through the water inlet pipe, and the water is evenly distributed under the action of the water distribution triangle cone. Micro-bubbles, the dissolved oxygen measurement and control device regulates the work of the blower according to the oxygen capacity to ensure that the dissolved oxygen in the aerobic contact oxidation pool water is greater than 2mg/L, and the treated wastewater flows out through the overflow weir and the outlet pipe;

⑥ A part of the sedimentation sludge in the aerobic contact oxidation tank is returned to the anaerobic reaction tank, and a part is used as the remaining sludge. The reacted water in the tank enters the sand filter tank through the outlet pipe, and is discharged after being filtered to meet the standard;

⑦ The excess sludge produced in the anaerobic reaction tank, multi-stage biochemical tank and aerobic contact oxidation tank is dehydrated and shipped out.

The beneficial effects of the present invention are: the present invention has simple structure, low manufacturing cost, relatively good deep effect on wastewater treatment in development zones, and convenient management.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a schematic structural view of an anaerobic reaction tank according to an embodiment of the present invention.

In Figure 1: 1. Anaerobic reaction tank, 1-1. Anaerobic reaction tank inlet pipe, 1-2. Sand collection area, 1-3. Sludge area, 1-4. Mixing area, 1-5. Collection Water area, 1-6. Slag collection area, 1-7. Anaerobic reaction tank stirring device, 1-8. Anaerobic reaction tank water branch pipe, 1-9. Anaerobic reaction tank three-phase separator, 1-10 .Overflow weir, 1-11. Slag scraper, 1-12. Scum tank, 1-13. Sediment discharge valve.

Fig. 2 is a schematic structural view of a multi-stage biochemical pool according to an embodiment of the present invention.

In Fig. 2: 2. multi-stage biochemical pool, 2-1. baffle plate, 2-2. first-level anaerobic reaction tank, 2-3. first-level aerobic reaction tank, 2-4. first-level Anoxic reaction pool, 2-5. Second-level aerobic reaction pool, 2-6. Second-level aerobic reaction pool, 2-7. Third-level aerobic reaction pool, 2-8. Multi-level biochemical pool Water pipe, 2-9. Multi-stage biochemical tank three-phase separator, 2-10. Multi-stage biochemical tank overflow weir, 2-11. Sludge discharge valve, 2-12. Upper cover, 2-13. Air collecting pipe, 2 -14. Aeration device, 2-15. Holes.

Fig. 3 is a schematic structural view of an aerobic contact oxidation tank according to an embodiment of the present invention.

In Figure 3: 3. Aerobic contact oxidation tank, 3-1. Inlet pipe of aerobic contact oxidation tank, 3-2. Water distribution triangle cone, 3-3. Aeration control system, 3-4. Membrane module, 3 -5. Aerobic contact oxidation tank overflow weir.

Fig. 4 is a process flow diagram of an embodiment of the present invention.

detailed description

The present invention is described in further detail now in conjunction with accompanying drawing. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, so they only show the configurations related to the present invention.

As shown in Figures 1 to 4, a mixed wastewater treatment system in a development zone of the present invention includes a wastewater regulating tank, an anaerobic reaction tank 1, a multi-stage biochemical tank 2, an aerobic contact oxidation tank 3 and a sand filter; The wastewater regulating tank, the anaerobic reaction tank, the multi-stage biochemical tank, the aerobic contact oxidation tank and the sand filter tank are connected in sequence.

The wastewater regulating pool includes a water inlet pipe and a water outlet pipe for regulating the water quality and water quantity of the mixed wastewater in the development zone.

The anaerobic reaction tank 1 includes a water inlet pipe 1-1 and an outlet pipe for discharging treated water, and the anaerobic reaction tank is sequentially composed of a sand collection area 1-2 and a sludge area 1-3 from bottom to top. , mixing zone 1-4 and separation zone; Described separation zone comprises catchment zone 1-5 and is positioned at the slag collection zone 1-6 in catchment zone; The sludge zone 1-3 of described anaerobic reaction tank and A stirring device 1-7 is arranged between the mixing area 1-4, and a water distribution branch pipe 1-8 is arranged above the stirring device, and the water distribution branch pipe is connected to the water inlet pipe 1-1; A three-phase separator 1-9 is provided, and the three-phase separator 1-9 includes a deflector and a triangular deflector ring located below the deflector and used in conjunction with the deflector, and the triangular deflector ring is installed on the On the inner wall of the anaerobic reaction tank, the upper part of the deflector has the same shape as the separation zone, the lower part of the deflector is trumpet-shaped, and the inner diameter of the lower part of the deflector is larger than the triangular deflector ring inner diameter; the upper part of the outer wall of the separation zone is provided with an overflow weir 1-10, and the overflow weir 1-10 is connected with the outlet pipe; Scum tank 1-12; when wastewater overflows from bottom to top, water and scum enter the lower part of the deflector through the triangular diversion ring, and the scum continues to enter the scum collecting area 1-6, and the water passes through the deflector The gap between the triangular diversion ring and the triangular diversion ring enters the catchment area 1-5; for better wastewater treatment, the water distribution branch pipe 1-8 is set in a concentric circle shape or a cross shape, and the water distribution branch pipe has a horizontal radiation Water outlet; due to the different densities of water and sediment, separation is achieved under the action of a three-phase separator; in order to discharge the treated sediment, a sediment discharge valve 1-13 is provided at the bottom of the anaerobic reaction tank;

The multi-stage biochemical pool 2 includes an anaerobic reaction pool 2-2 separated by a baffle plate 2-1, an aerobic reaction pool 2-3 and an anoxic reaction pool 2-4, and the first-stage anaerobic reaction pool The head end of the pool 2-2 is provided with an inlet pipe 2-8 for feeding waste water, the end of the first-stage aerobic reaction pool 2-3 is connected to the head end of the first-stage anoxic reaction pool 2-4, and the end of the second-stage aerobic reaction pool The end of the reaction pool 2-5 is connected with the head end of the second-stage anoxic reaction pool 2-6; the lower part of the baffle plate on the water inlet side of the reaction pool at each level is provided with a 45-degree corner to avoid water flow when entering. The impact of the impact effect, so as to play the role of buffering water flow and uniform water distribution; the end of the third stage aerobic reaction tank 2-7 is equipped with a three-phase separator 2-9 and overflow weir 2-10, and the overflow weir 2-10 is connected to the outlet pipe ; The first-stage anaerobic reaction pool 2-2 and the first-stage aerobic reaction pool 2-3, the first-stage anoxic reaction pool 2-3 and the second-stage aerobic reaction pool 2-3, the second-stage The anoxic reaction tank 2-4 and the third-stage aerobic reaction tank 2-4 are separated by baffle plates with holes 2-15, and the bottom of the aerobic reaction tank is equipped with an aeration device 2-14. Designed as a conical structure, the conical structure is connected to the sludge discharge valve 2-11; the first-stage anaerobic reaction pool 2-2 of the multi-stage biochemical pool, the first-stage anoxic reaction pool 2-4, the second-stage The upper cover 2-12 of the anoxic reaction tank 2-6 is designed as a conical structure, and the top of the conical structure is provided with a methane waste gas collecting pipe 2-13;

The middle and lower part of the aerobic contact oxidation tank 3 is provided with a water inlet pipe 3-1, and the lower part of the water inlet pipe 3-1 is provided with a water distribution triangle cone 3-2; the lower part of the water distribution triangle cone 3-2 is provided with an aeration Control system 3-3, the aeration control system 3-3 includes an aeration pan, a blower and a dissolved oxygen measurement and control device; further, the aeration pan is a microporous aeration pan with micropores evenly arranged The aeration pan is connected to the blower through the aeration pipe, and the blower is arranged outside the aerobic contact oxidation tank, and a dissolved oxygen measurement and control device is arranged on the top of the aerobic contact oxidation tank and under the wastewater surface, and the dissolved oxygen measurement and control device is based on oxygen The capacity-regulated blower works; the upper part of the water inlet pipe is built with a membrane module 3-4; the outlet of the aerobic contact oxidation tank is equipped with an overflow weir 3-5, and the water treated in this process enters the sand filter tank.

A part of the sludge in the aerobic contact oxidation tank 3 is returned to the anaerobic reaction tank through the sludge return pump for anaerobic phosphorus release, and a part is used as excess sludge. A kind of method that adopts the mixed wastewater treatment system of the development zone as claimed in claim 1 to carry out the method for wastewater treatment, has the following steps:

①The mixed wastewater in the development zone enters the wastewater regulating tank through the water inlet pipe to adjust the water quality and water quantity;

② Then the sewage enters the middle and lower part of the separation zone of the anaerobic reaction tank through the water inlet pipe 1-1; the stirring device 1-7 located under the water inlet pipe of the anaerobic reaction tank makes the solid matter in the sewage generate friction and removes other pollution on the solid matter matter; the floating matter in the sewage rises under the action of buoyancy, and rises to the slag collection area 1-6 under the action of the three-phase separator 1-9 in the anaerobic reaction tank, and under the action of the scum scraper 1-11, the scum Enter the scum tank 1-12 and be cleaned and transported; the sediment sinks to the sand collection area 1-2 at the bottom of the anaerobic reaction tank under the action of gravity, and passes through the sediment discharge valve 1-13 at the bottom of the anaerobic reaction tank Discharge; the water after separation and treatment enters the water collection area 1-5 of the anaerobic reaction tank under the action of the deflector in the three-phase separation area of the anaerobic reaction tank, and connects to the multi-stage biochemical tank through the overflow weir 1-10, the outlet pipe and the connecting pipe The water inlet pipe 2-8;

③ The water inlet pipe 2-8 of the first-stage anaerobic reaction tank through which the waste water passes enters the lower part of the multi-stage biochemical pool 2; after entering the multi-stage biochemical pool, the waste water advances up and down along the baffle plate 2-1. The aeration discs 2-14 located below the aerobic zones at all levels generate a large number of fine air bubbles to further rub the solids in the sewage, and at the same time oxidize the macromolecular substances in the wastewater into small molecular substances that are easy to absorb and adsorb. The waste water passes through the sludge bed of each reaction tank in the multi-stage biochemical tank in turn. The sludge in the reaction tank moves with the up and down flow of the waste water and the rise of biogas. The blocking effect of the baffle plate 2-1 and the sludge itself The sedimentation effect of the sludge reduces the flow rate of the sludge, so a large amount of sludge is trapped in the reaction tank, and the microorganisms in the reaction tank fully contact with the organic matter in the wastewater; the heterotrophic bacteria in the multi-stage biochemical tank convert the wastewater Suspended pollutants such as starch, fiber, carbohydrates, and soluble organic matter are hydrolyzed into organic acids, which decomposes macromolecular organic matter into small molecular organic matter, and converts insoluble organic matter into soluble organic matter;

④ After the wastewater reacted in the multi-stage biochemical tank, the three-phase separator 2-9 provided at the end of the third-stage aerobic reaction tank 2-7 realizes the separation of mud, water and methane gas, and the sludge is discharged under the action of gravity. Sink to the lower part of the multi-stage biochemical tank, and the excess sludge is discharged through the sludge discharge valve 2-11 at the bottom; the methane waste gas generated by the multi-stage biochemical tank is collected and discharged through the gas collecting pipe 2-13 at the top of the reaction tank; the waste water is discharged through the overflow weir, The water outlet pipe and the connecting pipe are connected to the water inlet pipe of the aerobic contact oxidation tank 3;

⑤ The waste water enters the middle and lower part of the aerobic contact oxidation tank 3 through the water inlet pipe 3-1, and the water is evenly distributed under the action of the water distribution triangle 3-2. The aeration tray produces a large number of microbubbles, and the dissolved oxygen measurement and control device regulates the work of the blower according to the oxygen capacity to ensure that the dissolved oxygen in the aerobic contact oxidation pool water is greater than 2mg/L, and the treated wastewater passes through the overflow weir 3-5 and outlet pipe flow out;

⑥ A part of the sedimented sludge in the aerobic contact oxidation tank 3 is returned to the anaerobic reaction tank 2, and a part is used as the remaining sludge. The reacted water in the tank enters the sand filter tank through the outlet pipe, and is discharged after being filtered to meet the standard;

⑦ The excess sludge produced in anaerobic reaction tank 1, multi-stage biochemical tank 2 and aerobic contact oxidation tank 3 is dehydrated and transported outside.

Inspired by the above-mentioned ideal embodiment according to the present invention, through the above-mentioned description content, relevant workers can make various changes and modifications within the scope of not departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, but must be determined according to the scope of the claims.

Claims (2)

1. A development zone mixed wastewater treatment system is characterized in that: comprise wastewater regulating pond, anaerobic reaction pond (1), multistage biochemical pond (2), aerobic contact oxidation pond (3) and sand filter pond; The regulating pool includes a water inlet pipe and a water outlet pipe for regulating the water quality and water quantity of the mixed wastewater in the development zone; The anaerobic reaction tank (1) includes a water inlet pipe (1-1) and an outlet pipe for discharging treated water, and the anaerobic reaction tank is sequentially composed of a sand collection area (1-2), A sludge area (1-3), a mixing area (1-4) and a separation area; the separation area includes a water collection area (1-5) and a slag collection area (1-6) located in the water collection area; A stirring device (1-7) is arranged between the sludge zone (1-3) and the mixing zone (1-4) of the anaerobic reaction tank, and a water distribution branch pipe (1-7) is arranged above the stirring device. 8), the water distribution branch pipe is connected to the water inlet pipe (1-1); a three-phase separator (1-9) is provided in the described separation zone, and the three-phase separator (1-9) includes a diversion plate and the triangular guide ring used in conjunction with the guide plate under the guide plate, the triangular guide ring is installed on the inner wall of the anaerobic reaction tank, and the upper part of the guide plate has the same shape as the separation area , the bottom of the deflector is trumpet-shaped, and the inner diameter of the lower part of the deflector is greater than the inner diameter of the triangular guide ring; the top of the outer wall of the separation zone is provided with an overflow weir (1-10), the The overflow weir (1-10) described above is connected to the water outlet pipe; the slag collection area (1-6) is equipped with a slag scraper (1-11) and a scum tank (1-12); the waste water flows from bottom to top When overflowing, water and scum enter the lower part of the guide plate through the triangular guide ring, and the scum continues to enter the slag collection area (1-6), and the water enters through the gap between the guide plate and the triangular guide ring. Water collection area (1-5); for better wastewater treatment effect, the described water distribution branch pipes (1-8) are arranged in the shape of concentric circles or crosses, with horizontal radiation outlets on the water distribution branch pipes; due to water, The density of the sediment is different, and the separation is realized under the action of the three-phase separator; in order to discharge the treated sediment, the bottom of the anaerobic reaction tank is provided with a sediment discharge valve (1-13); The multi-stage biochemical pool (2) comprises an anaerobic reaction pool (2-2), an aerobic reaction pool (2-3) and an anoxic reaction pool (2-4) separated by a baffle plate (2-1). ), the head end of the first-stage anaerobic reaction pool (2-2) is provided with an inlet pipe (2-8) for feeding waste water, and the end of the first-stage aerobic reaction pool (2-3) is connected to the first-stage The head end of the anoxic reaction pool (2-4) is connected, and the end of the second-stage aerobic reaction pool (2-5) is connected with the head end of the second-stage anoxic reaction pool (2-6); The lower part of the baffle on the water inlet side is provided with a 45-degree corner to avoid the impact of the water flow when it enters, so as to buffer the water flow and distribute water evenly; the third-stage aerobic reaction pool (2-7) The end is provided with a three-phase separator (2-9) and an overflow weir (2-10), and the overflow weir (2-10) is connected to the outlet pipe; the first-stage anaerobic reaction tank (2-2) and the first-stage well Oxygen reaction pool (2-3), the first level anoxic reaction pool (2-3) and the second level aerobic reaction pool (2-3), the second level anoxic reaction pool (2-4) and the third The baffles with holes (2-15) are used to isolate the first-level aerobic reaction tanks (2-4), and the aeration devices (2-14) are arranged at the bottom of the aerobic zone, and the bottom is designed as a conical structure , the conical structure connects the sludge discharge valve (2-11); the first-stage anaerobic reaction tank (2-2) of the multi-stage biochemical tank, the first-stage anoxic reaction tank (2-4), the second The upper cover (2-12) of the first-stage anoxic reaction tank (2-6) is designed as a conical structure, and the top of the conical structure is provided with a methane waste gas collecting pipe (2-13); A water inlet pipe (3-1) is set in the middle and lower part of the aerobic contact oxidation tank (3), and the lower part of the water inlet pipe (3-1) is provided with a water distribution triangle cone (3-2); the water distribution triangle cone (3-2) The lower part is provided with an aeration control system (3-3), and the aeration control system (3-3) includes an aeration pan, a blower and a dissolved oxygen measurement control device; further, the aeration The disc is a microporous aeration disc with micropores evenly arranged; the aeration disc is connected to a blower through an aeration pipe, and the blower is set outside the aerobic contact oxidation tank, and the upper part of the aerobic contact oxidation tank and the wastewater surface are set to dissolve An oxygen measurement and control device, the dissolved oxygen measurement and control device regulates the work of the blower according to the oxygen capacity; the upper part of the water inlet pipe has a built-in membrane module (3-4); the outlet of the aerobic contact oxidation tank is equipped with an overflow weir ( 3-5), the water treated in this process enters the sand filter; A part of the sludge in the aerobic contact oxidation tank (3) is returned to the anaerobic reaction tank through the sludge return pump for anaerobic phosphorus release, and a part is used as excess sludge. 2. a kind of method that adopts the mixed wastewater treatment system of development zone as claimed in claim 1 to carry out the method for wastewater treatment, has the following steps: ①The mixed wastewater in the development zone enters the wastewater regulating tank through the water inlet pipe to adjust the water quality and water quantity; ② Then the sewage enters the middle and lower part of the separation zone of the anaerobic reaction tank through the water inlet pipe (1-1); the stirring device (1-7) located under the water inlet pipe of the anaerobic reaction tank makes the solid matter in the sewage generate friction and removes the solid matter Other pollutants on the sewage; the floating matter in the sewage rises under the action of buoyancy, and rises to the slag collection area (1-6) under the action of the three-phase separator (1-9) in the anaerobic reaction tank, and is scraped on the slag scraper ( 1-11), the scum enters the scum tank (1-12) and is cleaned and transported; the sediment sinks to the sand collection area (1-2) at the lower part of the anaerobic reaction tank under the action of gravity, Discharge through the sediment discharge valve (1-13) at the bottom of the anaerobic reaction tank; the separated and treated water enters the water collection area (1-5) of the anaerobic reaction tank under the action of the deflector in the three-phase separation area of the anaerobic reaction tank , connecting the water inlet pipe (2-8) of the multi-stage biochemical tank through the overflow weir (1-10), the outlet pipe and the connecting pipe; ③The inlet pipe (2-8) of the first-stage anaerobic reaction tank through which the waste water passes enters the lower part of the multi-stage biochemical pool (2); after the waste water enters the multi-stage biochemical pool, advances up and down along the baffle plate (2-1); The aeration discs (2-14) below the aerobic zones at all levels generate a large number of fine air bubbles to further rub the solids in the sewage, and at the same time oxidize the macromolecules in the wastewater into small molecules that are easy to absorb and absorb; the wastewater passes through the The sludge bed in each reaction tank of the multi-stage biochemical tank, the sludge in the reaction tank moves with the up and down flow of wastewater and the rise of biogas, the blocking effect of the baffle (2-1) and the sludge itself The sedimentation effect reduces the flow rate of the sludge, so a large amount of sludge is trapped in the reaction tank, and the microorganisms in the reaction tank fully contact with the organic matter in the wastewater; the heterotrophic bacteria in the multi-stage biochemical tank convert the starch in the wastewater Suspended pollutants such as fibers, carbohydrates, and soluble organic matter are hydrolyzed into organic acids, which decomposes macromolecular organic matter into small molecular organic matter, and converts insoluble organic matter into soluble organic matter; ④Through the waste water after the multi-stage biochemical tank reaction, the three-phase separator (2-9) provided at the end of the third-stage aerobic reaction tank (2-7) realizes the separation of mud, water and methane gas, and the sludge is separated by gravity. sinks to the lower part of the multi-stage biochemical tank, and the excess sludge is discharged through the sludge discharge valve (2-11) at the bottom; the methane waste gas generated by the multi-stage biochemical tank passes through the gas collecting pipe (2-13) at the top of the reaction tank Collect and discharge; the waste water is connected to the inlet pipe of the aerobic contact oxidation tank (3) through the overflow weir, the outlet pipe and the connecting pipe; ⑤ waste water enters the middle and lower part of the aerobic contact oxidation tank (3) through the water inlet pipe (3-1), and distributes water evenly under the effect of the water distribution triangle cone (3-2), and the described aeration disc is evenly provided with The microporous microporous aeration disc produces a large number of microbubbles. The dissolved oxygen measurement and control device regulates the work of the blower according to the oxygen capacity to ensure that the dissolved oxygen in the aerobic contact oxidation pool is greater than 2 mg/L. The treated wastewater passes through The overflow weir (3-5) and the outlet pipe flow out; ⑥ A part of the sedimented sludge in the aerobic contact oxidation tank (3) flows back into the anaerobic reaction tank (2), and a part is used as excess sludge. The reacted water in the tank enters the sand filter tank through the outlet pipe, and reaches the standard after filtering emission; ⑦ The excess sludge produced in the anaerobic reaction tank (1), multi-stage biochemical tank (2) and aerobic contact oxidation tank (3) is dehydrated and transported outside.