An integrated device and method for biological treatment of COD and nitrogen-containing organic wastewater by A / O tower

Abstract

The present invention provides an integrated device for biological treatment of organic sewage containing COD and nitrogen in an A / O tower, comprising a cylinder; a water distribution area, a filtration area, a three-phase contact aerobic area, a nitrification liquid reflux discharge area and an anoxic area are arranged in sequence from top to bottom in the cylinder; the three-phase contact aerobic area is a normal pressure high oxygen biofilm filler area in a non-water accumulation area; a sewage inlet is arranged in the anoxic area; and the water outlet of the anoxic area is connected to the water inlet of the water distribution area. The device integrates water distribution, filtration, aerobic and anoxic, saving floor space. The device has a high pollutant removal load per unit volume. The aerobic area can synergistically treat the odor generated in the anoxic area; the COD, ammonia nitrogen and total nitrogen battery removal rates are high.

Description

Technical Field

[0001] The invention belongs to the technical field of biological treatment of sewage, and in particular relates to an integrated device and method for biological treatment of organic sewage containing COD and nitrogen by an A / O tower. Background Art

[0002] At present, the sewage biological treatment processes and devices widely used at home and abroad all adopt the method of cultivating biological bacteria in sewage, including anaerobic, anoxic and aerobic methods. The bacteria are in a floating state, which is the activated sludge method, and the bacteria are attached to the surface of various fillers, which is the contact oxidation method, the biological rotary disc method, etc. The above-mentioned processes and devices have their advantages and are currently widely used in the fields of urban sewage treatment, rural domestic sewage and industrial organic sewage treatment. However, due to the characteristics of the existing processes: (1) liquid and solid two-phase contact oxygen supply, the aerobic activated sludge or contact oxidation process with the largest capacity and the most important function requires water accumulation in the pool, and it is necessary to continuously flush air to the aeration head and aeration pipe at the bottom of the pool through a high-pressure fan to ensure that the sewage has sufficient dissolved oxygen to ensure that the organisms and microorganisms in the sewage treatment pool obtain the oxygen needed for breathing. The microorganism obtains oxygen through a process in which the sewage containing dissolved oxygen contacts the biofilm and the microorganism absorbs the dissolved oxygen in the water. It is a liquid and solid two-phase contact oxygen supply system; (2) the facultative aerobic tank, aerobic tank and sedimentation tank are all set up separately and independently, and arranged in a flat stepped manner.

[0003] However, the existing process also has the following disadvantages: (1) Microorganisms can only absorb dissolved oxygen in sewage. Since the solubility of oxygen in water is only 6.84 ml / l, it cannot provide the oxygen demand of high-density biological flora, and cannot cultivate advantageous aerobic biological strains with high oxygen consumption, high activity and high degradation performance; (2) The walls and bottom of the sewage treatment pool need to withstand high pressure and need to be leak-proof; the high-pressure fan needs to be installed independently, and the construction cost of the fan room is high; (3) The high-pressure fan continuously supplies air to the aeration head or aeration pipe combination at the bottom of the sewage pool, and the high-pressure fan, aeration head or aeration pipe combination equipment is expensive; (4) The high-pressure fan has high energy consumption; (5) In order to optimize the construction cost and gas supply cost of the aerobic biochemical pool, the pool depth is usually controlled at 3 to 5 meters, and due to the heavy operating weight, it can only be arranged independently in a plane, resulting in a large area of ​​the aerobic pool; (6) The anoxic pool produces odor, hydrogen sulfide, and ammonia that pollute the environment, and needs to be covered and collected to build waste gas treatment facilities. The high-pressure fan has a large noise and pollutes the environment.

[0004] Therefore, the existing technology has the following defects for newly built sewage treatment plants: large land area, high investment, high fan energy consumption, high operating cost, serious odor of exhaust gas from anoxic pool, loud noise from high-pressure fans, and it is impossible to implement on-site upgrading and transformation projects for treatment facilities with no site or few sites and pollutant discharge water quality that does not meet the standard requirements. Summary of the invention

[0005] In view of this, the object of the present invention is to provide an integrated device and method for A / O tower biological treatment of COD and nitrogen-containing organic wastewater, which integrates anoxic, water distribution, filtration, aerobic and sedimentation, and has a high pollutant removal efficiency.

[0006] The present invention provides an integrated device for biologically treating organic sewage containing COD and nitrogen with an A / O tower, comprising a cylinder;

[0007] The cylinder is provided with a water distribution area, a filtration area, a three-phase contact aerobic area, a nitrification liquid reflux discharge area and anoxic area in sequence from top to bottom;

[0008] The three-phase contact aerobic zone is a normal pressure high oxygen biofilm filler zone in a non-waterlogged area;

[0009] A sewage inlet disposed in the anoxic zone;

[0010] The water outlet of the anoxic zone is connected with the water inlet of the water distribution zone.

[0011] The three-phase contact aerobic zone includes a cyclonic air supply zone and an aerobic zone arranged directly above the cyclonic air supply zone;

[0012] A low-pressure fan is provided on the cylinder wall of the cyclone air supply zone to provide low-pressure air to the cyclone air supply zone through an air inlet;

[0013] The cyclone air supply area is communicated with the nitration liquid reflux discharge area.

[0014] Preferably, the device further comprises a sedimentation clean water discharge unit; the sedimentation clean water discharge unit is provided with a sludge discharge port and a sludge discharge pipe connected to the discharge port;

[0015] The sludge discharge pipe is provided with an excess sludge discharge port and a return sludge control valve; the return sludge control valve transports the return sludge and the sewage treated in the anoxic zone to the water distribution zone;

[0016] The sedimentation clean water discharge unit is arranged inside the cylinder, between the nitrification liquid reflux discharge area and the anoxic area; or arranged outside the cylinder;

[0017] Part of the nitrification liquid in the nitrification liquid reflux discharge area is discharged into the sedimentation clean water discharge unit.

[0018] Preferably, if the sedimentation water discharge unit is arranged outside the cylinder;

[0019] The nitrification liquid reflux discharge area in the cylinder includes a nitrification liquid collection tank;

[0020] A nitrification liquid discharge port and an exhaust hole are arranged at the bottom of the nitrification liquid collecting tank; the nitrification liquid discharge port is connected to a nitrification liquid guide pipe; the exhaust hole discharges the gas generated in the anoxic zone to the cyclone gas supply zone;

[0021] and a nitrification liquid diversion well connected to the nitrification liquid diversion pipe, wherein a nitrification liquid reflux port and a nitrification liquid discharge port are provided at the lower part of the nitrification liquid diversion well;

[0022] The nitrification liquid reflux port is communicated with the anoxic zone; the nitrification liquid discharge port is connected to the water inlet of the sedimentation clean water discharge unit located outside the cylinder through a pipeline.

[0023] Preferably, if the sedimentation clean water discharge unit is disposed in the cylinder, the nitrification liquid reflux discharge area in the cylinder includes a nitrification liquid collection tank;

[0024] An exhaust-nitrification liquid guide pipe 17-1 and a central guide tube 19-1 are arranged at the bottom of the nitrification liquid collection tank;

[0025] The exhaust-nitrification liquid guide pipe discharges the gas in the anoxic zone to the cyclone gas supply zone and directs part of the nitrification liquid into the sedimentation clean water discharge unit through the central guide tube;

[0026] Another part of the nitrification liquid in the nitrification liquid reflux discharge area flows back to the anoxic area through the exhaust gas-nitrification liquid guide pipe 17-1 passing through the sedimentation clean water discharge unit.

[0027] Preferably, the filter area is a quartz sand, ordinary sand, granular activated carbon filter material particle filter layer, mesh filter plate or porous filter plate with a particle size of 3 to 50 mm and a thickness of 50 to 300 mm.

[0028] Preferably, if the sedimentation clean water discharge unit is disposed in the cylinder, an annular overflow groove is provided on the inner wall of the cylinder of the sedimentation clean water discharge unit;

[0029] A clean water discharge port is arranged on the outer wall of the cylinder corresponding to the annular overflow groove.

[0030] The present invention provides a method for treating urban and rural domestic sewage using the integrated device described in the above technical solution, comprising the following steps:

[0031] The urban and rural domestic sewage to be treated is treated in the anoxic zone, the effluent is lifted and transported, and then distributed, and then filtered, aerobic treated, nitrified liquid reflux discharged and sludge sedimentation reflux clean water discharged in sequence to obtain treated sewage.

[0032] Preferably, during the anoxic treatment, the anoxic bacteria sludge concentration is 15-30% V / V; the dissolved oxygen concentration is 0.2-0.6 mg / L; the residence time is 3-8 hours, and the denitrification carbon source dosage concentration controls the C / N ratio to be 3-5:1;

[0033] During aerobic treatment, the density of the filler used in the aerobic zone is 50-60% V / V; the wind pressure in the air supply zone is 50-1000 Pa; and the reflux ratio of the nitrifying liquid is 2.0-3.0:1.

[0034] Preferably, the COD- and nitrogen-containing organic wastewater to be treated includes one or more of the COD- and nitrogen-containing organic wastewaters generated in towns, rural areas, agglomeration areas and industries.

[0035] The present invention provides an integrated device for biological treatment of organic sewage containing COD and nitrogen in an A / O tower, comprising a cylinder; a water distribution area, a filtration area, a three-phase contact aerobic area, a nitrification liquid reflux discharge area and an anoxic area are arranged in sequence from top to bottom in the cylinder; the three-phase contact aerobic area is a normal-pressure high-oxygen biofilm filler area in a non-water accumulation area; a sewage inlet is arranged in the anoxic area; and the water outlet of the anoxic area is connected to the water inlet of the water distribution area. The device integrates water distribution, filtration, three-phase contact aerobic, nitrification liquid reflux discharge and anoxic, saving floor space. The device has a high pollutant removal load per unit volume. The aerobic area can synergistically treat the odor generated in the anoxic area; the COD, ammonia nitrogen and total nitrogen battery removal rates are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of an apparatus for efficiently treating urban and rural sewage with an A / O tower provided by the present invention; wherein, 1 is an anoxic zone, 2 is an aerobic zone, 3 is a cyclone air supply zone, 4 is a sedimentation zone, 5 is a water inlet, 6 is a carbon source addition port, 7 is a submersible agitator, 8 is a sampling detection port, 9 is an anoxic flow control valve, 10 is a lifting pump, 11 is a lifting main valve, 12 is a water distribution pipe, 13 is a filtration system, 14 is a filler bracket, 15 is a filler, 16 is a low-pressure fan, 17-1 is an exhaust-nitrification liquid guide pipe, 18 is a nitrification liquid collection tank, 19-1 is a central guide tube, 20-1 is a conical water baffle, 21-1 is an annular overflow tank, 22-1 is a clean water discharge port, 23-1 is a conical sludge shaker, 24 is an excess sludge discharge port, 25 is a return sludge control valve, and 26 is a cylinder.

[0037] Figure 2 Schematic diagram of another device for efficiently treating urban and rural sewage with an A / O tower provided by the present invention; wherein 4-2 is a nitrification liquid diversion well, 17-2 is a nitrification liquid diversion pipe, 19-2 is an exhaust hole, 20-2 is a nitrification liquid reflux control valve, 21-2 is a nitrification liquid lifting pump, 22-2 is a water inlet to a sedimentation tank, 23-2 is a mud discharge port from a sedimentation tank, 27 is a nitrification liquid reflux port, and the names of other reference numerals are the same Figure 1 Corresponding numbers in . DETAILED DESCRIPTION

[0038] The present invention provides an integrated device for biologically treating organic sewage containing COD and nitrogen with an A / O tower, comprising a cylinder;

[0039] The cylinder is provided with a water distribution area, a filtration area, a three-phase contact aerobic area, a nitrification liquid reflux discharge area and anoxic area in sequence from top to bottom;

[0040] The three-phase contact aerobic zone is a normal pressure high oxygen biofilm filler zone in a non-waterlogged area;

[0041] A sewage inlet disposed in the anoxic zone;

[0042] The water outlet of the anoxic zone is connected with the water inlet of the water distribution zone.

[0043] The device integrates water distribution, filtration, three-phase contact aerobic, nitrification liquid reflux discharge and anoxic, saving floor space. The device has a high pollutant removal load per unit volume. The aerobic zone can synergistically treat the odor generated in the anoxic zone; the COD, ammonia nitrogen and total nitrogen battery removal rates are high.

[0044] See also Figure 1 and Figure 2 ; Figure 1 A schematic diagram of a device for efficiently treating organic sewage from towns, rural areas, industries, etc. with an A / O tower provided by the present invention; Figure 2 This is another schematic diagram of a device for efficiently treating organic sewage from towns, rural areas, industries, etc. using an A / O tower provided by the present invention.

[0045] In the present invention, the anoxic zone is arranged at the lower part of the integrated device;

[0046] In the district:

[0047] a. Under anaerobic conditions, refractory organic matter is hydrolyzed into small molecules that are easily degradable;

[0048] b. Convert organic nitrogen in sewage into ammonia nitrogen. The reaction formula is as follows:

[0049] Ammonification of organic nitrogen under anaerobic conditions:

[0050] (CH3)4NOH+O2→(CH3)3N+HCHO

[0051] (CH3)3N+O2→(CH3)2NH+HCHO

[0052] (CH3)2NH+O2→CH3NH2+HCHO

[0053] CH3 NH2+O2→NH3+HCHO

[0054] c. The nitrate nitrogen in the nitrification liquid of the three-phase contact aerobic zone is refluxed to the anoxic zone and converted into nitrogen gas under the action of denitrifying bacteria under anoxic conditions. The reaction formula is as follows:

[0055]

[0056] d. The effluent from the anoxic zone and the sludge returned from the sludge sedimentation return clean water discharge zone are combined and pumped to the water distribution zone;

[0057] e. The odor, nitrogen and other gases generated in the anoxic zone are discharged to the gas supply zone of the three-phase contact aerobic zone through the exhaust pipe penetrating the sedimentation zone;

[0058] f. The carbon source required for the anoxic zone is added through the carbon source feeding port 6.

[0059] The anoxic zone 1 includes an anoxic tank, and a stirring device for preventing sludge from settling is installed at the bottom of the anoxic tank, namely a submersible agitator 7, and the submersible agitator can be an underwater stirring pump, a submersible mixer or a hydraulic agitator;

[0060] The anoxic zone is provided with a sewage inlet 5. The anoxic pool is provided with a carbon source feeding port 6;

[0061] The anoxic zone can be provided with COD, dissolved oxygen, nitrate nitrogen, and ammonia nitrogen automatic monitoring devices at the bottom as needed. A sampling detection port 8 is provided on the anoxic pool; the sampling detection port 8 is used as a monitoring port or online monitor for the determination of ammonia nitrogen, nitrate nitrogen, COD, and DO.

[0062] The anoxic area and the water distribution area are connected through a pipeline, and a lifting device for lifting sewage is provided on the pipeline. The lifting device includes a lifting pump 10 and a lifting main valve 11.

[0063] In the present invention, the water outlet of the anoxic zone is connected to the water inlet of the water distribution area; the lifting pump 10 lifts the treated sewage in the anoxic zone to the water distribution area through the pipeline. A sampling detection port 8 and an anoxic flow control valve 9 are provided on the pipeline between the water outlet of the anoxic zone and the lifting pump.

[0064] In the present invention, the water distribution area is located at the top of the A / O tower; the water distribution area includes a water distribution device; the water distribution device allows the sewage to drip into the filtration area more evenly at the inlet level. The water distribution device can be a serrated water distribution trough, a perforated water distribution pipe, a water faucet, or a rotary perforated pipe water distributor. The perforation diameter of the perforated water distribution pipe 12 is 5 to 30 mm, and the perforation spacing is 100 to 300 mm; the vertical height of the water outlet of the water distribution device from the filtration area is preferably 200 to 800 mm.

[0065] After passing through the water distribution area, the sewage flows to the filtration area. The filtration area is arranged between the water distribution area and the three-phase contact aerobic area; the filtration area can filter out the lumps, particles, and floating objects in the sewage to prevent the system from being blocked. The filtration area includes a filtration system 13, which is selected from quartz sand with a particle size of 3 to 50 mm and a thickness of 50 to 300 mm, ordinary sand, granular activated carbon filter material particle filter layer, mesh filter plate or porous filter plate.

[0066] The three-phase contact aerobic zone is arranged between the filtration zone and the nitrification liquid reflux discharge zone; the three-phase contact aerobic zone is a non-water accumulation zone normal pressure high oxygen biofilm filler zone; the oxygen concentration of the three-phase contact aerobic zone is 23-26%; the pressure is 50Pa-1000Pa. The dissolved oxygen concentration of the water accumulation type aerobic zone in the prior art is 6-7mg / l, and the pressure is 40000-70000Pa.

[0067] The three-phase contact aerobic zone includes a cyclone air supply zone 3 and an aerobic zone 2 arranged directly above the cyclone air supply zone; a low-pressure fan 16 is provided on the cylinder wall of the cyclone air supply zone to provide low-pressure air to the cyclone air supply zone through an air inlet. The cyclone air supply zone is connected to the nitrification liquid reflux discharge zone. The three-phase contact aerobic zone has the following functions:

[0068] a. Absorb and degrade organic matter in sewage. Organic matter is absorbed as nutrients by the film-like aerobic organisms attached to the biological filler. The film-like aerobic organisms need to be continuously provided with oxygen required for the respiratory process to produce activity. The activity of aerobic organisms can be greatly improved in an oxygen-rich state, while also increasing the absorption and degradation rate of organic pollutants. When the device is running, the biofilm attached to the surface of the filler is exposed to the air, and the sewage containing biological bacteria contacts the biofilm in a dripping state from top to bottom. The muddy bacteria in the sewage droplets and the biofilm bacteria attached to the filler obtain the oxygen needed for breathing by absorbing oxygen in the air and dissolved oxygen in the water layer on the surface of the biofilm. This is a process of mass transfer in which the gas, liquid and solid phases are in contact, so that the biofilm obtains the oxygen needed for breathing. Since the oxygen content in the air is about 25%, and the solubility of oxygen in water is only 6.84 ml / l, the oxygen content of the former is greatly increased than that of the latter. The use of air and a thin layer of water on the surface of the biofilm to directly contact the organisms and microorganisms in the biofilm to produce an oxygen-rich state can greatly increase the number and activity of organisms and microorganisms in the unit volume of the treatment device, and can cultivate more dominant bacteria with large oxygen consumption, strong biological activity and strong pollutant degradation ability, thereby increasing the pollutant removal load per unit volume of the treatment device. The air is input from the bottom to the top by a low-pressure blower or fan located at the bottom of the tower, and can also be naturally input through the pores of the permeable cylinder;

[0069] b. Nitrification: ammonia nitrogen is nitrified into nitrate nitrogen under the action of aerobic bacteria. The reaction formula is:

[0070] NH4 + +O2+HCO3 ˉ →NO2 - +C5 H7O2 N+H2O+H2CO3

[0071] NO2 - +NH4 + +H2CO3+HCO3 -+O2→C5H7O2N+NO3 ˉ ;

[0072] c. The nitrification liquid refluxes and discharges into the sedimentation tank. The nitrification liquid flowing out of the nitrification liquid collecting tank at the bottom of the cyclone gas supply zone in the zone flows partly into the anoxic zone at the bottom of the tower by gravity, and partly flows into the subsequent sedimentation clean water discharge unit by gravity or pump lifting. The reflux ratio is adjusted by adjusting the nitrification liquid reflux control valve, and the ratio of the reflux water volume to the water volume entering the sedimentation zone is 1 to 3;

[0073] d. Deodorization: the malodorous gas and nitrogen generated from the anoxic zone at the bottom pass through the exhaust pipe of the sedimentation zone into the air supply zone of the three-phase contact aerobic zone, mix with the air, and then flow up to the aerobic three-phase contact zone for biological deodorization. No deodorized gas is discharged from the top of the tower. This is a preferred and most environmentally friendly deodorization technology;

[0074] e. A low-pressure fan 16 is provided in the cyclone air supply area; the low-pressure fan supplies air with a fan pressure of 50 to 1000Pa, which is a low-energy consumption process. One or more low-pressure fans installed on the peripheral wall of the device continuously input compressed air into the air supply area of ​​the three-phase contact aerobic (O) process, and a cyclone is formed in the air supply area. The compressed air in the air supply area flows through the cavities between the biofilms and water droplets in the biological contact oxidation area and is discharged at the top. The technical indicators are: wind pressure 50 to 1000Pa, compressed air flow rate 5mm / s to 100mm / s; control method: according to the measured dissolved oxygen index of the nitrification liquid, the number of fans used or the fan speed is controlled to adjust the air supply volume. The oxygen required for aerobic bacteria to breathe in the device is obtained by continuously delivering air. Low-pressure air is mixed with odor and nitrogen from the anoxic process in the air supply chamber to form a vortex. The pressure difference between the air supply chamber and the contact area of ​​aerobic bacteria is used to flow through the air cavity between the biofilms. Excess oxygen-containing air and gas exhaust are discharged from the top of the tower. The oxygen supply system does not require aeration heads or aeration pipes.

[0075] The inner upper part of the three-phase contact aerobic zone is provided with a filler bracket 14 installed in parallel with the upper and lower parts; the bracket is made of a firm metal, plastic, nylon or other materials that are not easy to age, and the spacing between two adjacent brackets is 100-200mm. The upper and lower vertical, fixed at both ends, with a high specific surface area, and used for attaching biofilms are installed between the brackets, and the installation spacing of adjacent fillers is 50-200mm. The installation of the filler layer can be pre-made into a module and assembled on site; the installation of the three-phase contact aerobic zone can be single-layer or multi-layer; the height of the filler layer is 3000-15000mm. The installation of the filler adopts a bracket bundling type or a layered stacking type. The bracket bundling type is to fix the filler on a strip made of a material with good firmness and low elasticity such as plastic, nylon or metal, and then the upper and lower ends of several strips with fillers are respectively fixed on the additional bracket to form a filler layer; the layered stacking type is to directly stack the block filler on a mesh bracket with a hole diameter smaller than the filler particle diameter at the bottom, which can be composed of multiple filler layers.

[0076] The tower wall structure of the three-phase contact aerobic zone: this zone operates in a non-waterlogged state in the cylinder, and has no requirements for lateral pressure resistance and anti-seepage. The surrounding wall only needs to be assembled with ordinary or thermal insulation plates made of corrosion-resistant metal or plastic materials by welding, concave-convex groove embedded bolts, etc.

[0077] One or more low-pressure fans are arranged on the cylinder wall of the cyclone air supply area, and the wind pressure of the low-pressure fans is 50-1000 Pa, and the air volume is determined according to the processing capacity. A nitrification liquid collection tank 18 is arranged at the bottom of the cyclone air supply area; the nitrification liquid collection tank is arranged in a plane; the tank depth of the nitrification liquid collection tank is 100-500 mm.

[0078] The device also includes a sedimentation clean water discharge unit; the sedimentation clean water discharge unit is provided with a sludge discharge port and a sludge discharge pipe connected to the discharge port; the sludge discharge pipe is provided with an excess sludge discharge port 24 and a return sludge control valve 25; the return sludge control valve transports the return sludge and the sewage treated in the anoxic zone to the water distribution zone; the sedimentation clean water discharge unit is arranged in the cylinder, between the nitrification liquid return discharge zone and the anoxic zone; or arranged outside the cylinder; part of the nitrification liquid in the nitrification liquid return discharge zone is discharged into the sedimentation clean water discharge unit. The sedimentation clean water discharge unit uses a sedimentation method to separate the mud and water from the mud-water mixture from the nitrification liquid collection tank, and the obtained clean water is discharged; part of the obtained sedimentation sludge is dehydrated and dried in the sludge drying equipment, and part of the sludge is returned and merged into the outlet pipe of the anoxic zone. The present invention controls the sludge return ratio through the return sludge control valve 25, and the sludge return amount / clean water discharge amount = 0.3 to 0.8:1. The excess sludge is discharged through the excess sludge discharge port 24 .

[0079] In the present invention, if the sedimentation water discharge unit is arranged outside the cylinder;

[0080] The nitrification liquid reflux discharge area in the cylinder includes a nitrification liquid collection tank;

[0081] A nitrification liquid discharge port and an exhaust hole 19-2 are provided at the bottom of the nitrification liquid collecting tank; the nitrification liquid discharge port is connected to the nitrification liquid guide pipe 17-2; the exhaust hole 19-2 discharges the gas generated in the anoxic zone to the cyclone gas supply zone; and a nitrification liquid diversion well 4-2 is connected to the nitrification liquid guide pipe, and the lower part of the nitrification liquid diversion well is provided with a nitrification liquid reflux port 27 and a nitrification liquid discharge port;

[0082] The nitrification liquid reflux port is communicated with the anoxic zone; the nitrification liquid discharge port is connected to the water inlet of the sedimentation clean water discharge unit through a pipeline.

[0083] A nitrification liquid reflux control valve 20-2 is provided on the pipeline between the nitrification liquid outlet and the water inlet 22-2 of the sedimentation tank. The nitrification liquid is discharged to the sedimentation tank through the nitrification liquid lifting pump 21.

[0084] In the present invention, if the sedimentation clean water discharge unit is disposed in the cylinder, the nitrification liquid reflux discharge area in the cylinder includes a nitrification liquid collection tank 18;

[0085] An exhaust-nitrification liquid guide pipe 17-1 and a central guide tube 19-1 are arranged at the bottom of the nitrification liquid collection tank;

[0086] The exhaust-nitrification liquid guide pipe 17-1 discharges the gas in the anoxic zone to the cyclone gas supply zone and passes part of the nitrification liquid through the central guide tube into the sedimentation clean water discharge unit;

[0087] Another part of the nitrification liquid in the nitrification liquid reflux discharge area flows back to the anoxic area through the exhaust gas-nitrification liquid guide pipe 17-1 passing through the sedimentation clean water discharge unit.

[0088] The sedimentation clean water discharge unit can be arranged in the same tower body between the three-phase contact aerobic zone and the anoxic zone as needed, or can be arranged outside the tower body; it is operated by sewage inlet lifting sludge self-flowing reflux or sewage self-flowing sludge lifting reflux; if the sedimentation clean water discharge unit is arranged in the cylinder body, the cylinder inner wall of the sedimentation clean water discharge unit is provided with an annular overflow groove 21-1; the cylinder outer wall corresponding to the annular overflow groove is provided with a clean water discharge port 22-1. A serrated overflow port is arranged above the annular overflow groove; a conical sludge shake 23-1 is arranged below the cylinder overflow groove, and a flow meter and a flow control valve are installed in the sludge return pipe of the sludge discharge system at the bottom of the conical sludge shake; part of the sludge after solid-liquid separation in the sedimentation device is returned to the anoxic zone for reprocessing, and part of the sludge is dehydrated and dried; the supernatant of the sedimentation solid-liquid separation layer is discharged when it meets the standards.

[0089] The sedimentation clean water discharge unit includes a sedimentation area 4, a central guide tube 19-1 is arranged at the center of the sedimentation area, the upper end of the guide tube is flush with the nitrification liquid collection tank or the upper end of the guide tube is higher than the bottom of the nitrification liquid collection tank, and a conical water baffle 20-1 is arranged at the lower end of the guide tube; an overflow tank and a clean water discharge port are arranged around the upper part of the sedimentation tank; a conical sludge hopper is arranged at the bottom of the sedimentation tank, and a sludge discharge pipe and a sludge discharge valve and a sludge return flow control valve arranged on the sludge discharge pipe are connected to the bottom of the conical sludge hopper; the sludge is returned to the filtration area. The treated sewage is discharged through the clean water discharge port 22-1.

[0090] For A / O towers with large sewage treatment volume and large cross-sectional area of ​​the cylinder, the sedimentation and clear water discharge unit is preferably not set in the same tower. The cylinder is equipped with a lifting pump, carbon source addition, sewage, sludge, electricity, and gas supply control facilities outside the cylinder, which are the water inlet flow regulating valve and flow meter connected to the water inlet and sewage port arranged outside the cylinder or attached to the outer wall of the cylinder; the anoxic mixed liquid lifting pump, flow regulating valve and flow meter connected to the anoxic process outlet; the fan, lifting pump switch and flow frequency conversion control facilities.

[0091] In the integrated device provided by the present invention, the anoxic zone, water distribution zone, filtration zone, three-phase contact aerobic zone and sedimentation clean water discharge unit are arranged in one tower device according to the design scale of sewage treatment, the permission of sewage treatment land, etc. In the present invention, the anoxic hydrolysis zone is preferably arranged below the ground, and the filtration zone and the three-phase contact aerobic zone are arranged above the ground.

[0092] The above-mentioned integrated device is used to treat nitrogen-containing wastewater. The wastewater only needs to be lifted once, and oxygen and air are supplied by a low-pressure blower or fan, which has low energy consumption and low noise. The pollutant (COD, ammonia nitrogen, total nitrogen, odorous gas, etc.) removal load and efficiency are significantly improved compared with the existing planar A / O treatment process.

[0093] In summary, the device provided by this application has the following advantages compared with the prior art:

[0094] (1) Comparison of oxygen supply effect and treatment effect: 1. Oxygen supply effect. The present invention adopts a three-phase contact gas supply method to supply oxygen. Compared with the existing A / O method two-phase contact biological oxidation method, the boundary oxygen content of the biological strain is theoretically increased from 0.684 mg / l in the prior art to 25%, which is greatly improved; 2. Treatment effect. The biological microorganisms in the device grow and reproduce in an oxygen-rich state, which greatly improves the strain density and biological activity of the treatment device, and can cultivate more advantageous strains with large oxygen consumption, strong biological activity, and strong pollutant degradation ability, thereby improving the pollution per unit volume of the treatment device. The removal load of pollutants is better than the "Urban Sewage Treatment Plant Pollutant Discharge Standard" (GB18718-2002) when applied to urban sewage treatment plants, and better than the "Zhejiang Rural Domestic Sewage Treatment Facility Water Pollutant Discharge Standard" (DB33 / 973-2015) when applied to rural biochemical sewage treatment terminals; when applied to industrial organic wastewater treatment, the effluent COD, ammonia nitrogen and total nitrogen are better than the first-level standard of the "Comprehensive Sewage Discharge Standard" (GB8978-1996);

[0095] (2) Energy consumption comparison: Compared with the existing A / O method high-pressure air supply technology, the low-pressure air supply technology adopted by the present invention reduces the fan pressure from 40,000 to 70,000 Pa to 50 to 1,000 Pa. The low-pressure fan replaces the high-pressure fan, and the fan saves 50 to 70% of energy consumption. The lifting pump energy consumption, the present invention flows into the anoxic pool located underground by gravity, and the nitrification liquid flows back to the anoxic pool by gravity. The sewage is only lifted once, but the lifting amount is the sum of the lifting before the anoxic pool of the existing A / O method sewage and the lifting of the nitrification liquid backflow. The sewage lifting height is higher than the existing A / O biochemical pool because the height of the A / O tower of the present invention is higher, and the corresponding energy consumption increases by about 20%. The comprehensive energy consumption of the present invention is saved by about 20 to 30% compared with the existing A / O method. There is no need to build a fan room, install an aeration head or aeration pipe, and the technical construction investment does not generate noise pollution.

[0096] (3) Comparison of land occupation of buildings and structures: The vertical stacking technology of each process of the present invention. Compared with the existing A / O method flat step-by-step setting technology, the vertical stacking technology of the process makes the aerobic process, which occupies about 3 times the area of ​​the anoxic process, be superimposed on the anoxic pool, so that the aerobic process has zero land occupation; the present invention does not need to build a fan room, saving the fan room area compared with the existing A / O method. It saves 50-70% of land. Compared with the simple A / O + artificial wetland method for rural domestic sewage treatment, it saves 60-80% of land.

[0097] (4) Construction cost comparison: Considering that the three phase contact aerobic (O), filtration and water distribution zones of the device are all operated without water accumulation, the peripheral wall of this zone only needs to withstand a wind pressure of 50-1000Pa. The peripheral wall of the present invention adopts ordinary plates or protective plates such as lightweight thin-walled metal and plastic, and the peripheral wall has no anti-leakage requirements and is assembled by welding, concave and convex grooves embedded with bolts, etc., with low material cost and quick installation. The cost of the peripheral wall is 60-70% lower than that of the existing A / O method pool wall (which needs to bear pressure and prevent leakage, and needs to build thick reinforced concrete or thick steel plate pool wall). Compared with the existing A / O method, the equipment cost reduces the fan cost and eliminates the purchase and installation cost of aeration pipes, valves and heads of the air distribution system; however, compared with the existing A / O method, the present invention needs to add a water distribution system, and compared with the activated sludge method, it needs to add a filler bracket and filler, and the construction cost increases by 30-50%. Compared with the existing A / O method, the comprehensive construction cost of the present invention saves about 20%.

[0098] (5) Comparison of operating environment: 1. Deodorization effect. The anoxic (A) process of the present invention produces ammonia, hydrogen sulfide, and odor. The odor rises to the low-pressure air supply chamber and mixes with air to form a mixed gas cyclone. The odor is synergistically input into the three-phase contact aerobic zone located above for biological deodorization, and contacts with biological bacteria in sewage droplets and biofilm bacteria attached to the filler. Aerobic biofilm bacteria absorb organic plant nutrients in sewage and use oxygen in the air as a respiratory oxygen source to degrade COD and ammonia nitrogen in sewage into nitrate nitrogen. At the same time, they absorb ammonia, hydrogen sulfide, and odor in the mixed gas, so that ammonia is nitrated into nitrate nitrogen, hydrogen sulfide is oxidized into sulfur, and the odor is purified by biofilm adsorption with a high specific surface area, producing a synergistic treatment effect of odor. The odor concentration at the top of the tower reaches the "Emission Standard of Odor Pollutants" (GB14554-93) ammonia <1.5mg / m 3 、Hydrogen sulfide <0.061.5mg / m 3 , odor concentration <20 (dimensionless), the existing A / O process anoxic (A) process produces ammonia, hydrogen sulfide, and odor that exceed the standard and needs to be covered and collected and equipped with waste gas treatment facilities. For experimental data, see the case. 2. Noise reduction effect, the present invention uses a 50-1000Pa low-pressure fan to replace a 40000-70000Pa high-pressure fan, and the equipment noise is reduced from the original 80-85 decibels to below 60 decibels.

[0099] The present invention provides a method for treating organic sewage in towns, rural areas, industries, etc. by using the integrated device described in the above technical solution, comprising the following steps:

[0100] The urban and rural domestic sewage to be treated is treated in the anoxic zone, the effluent is lifted and transported, and then distributed, and then filtered, aerobic treated, nitrified liquid reflux discharged and sludge sedimentation reflux clean water discharged in sequence to obtain treated sewage.

[0101] In the present invention, during anoxic treatment, the anoxic bacteria sludge concentration is 15-30% V / V; the dissolved oxygen concentration is 0.2-0.6 mg / L; the residence time is 3-8 hr, and the denitrification carbon source dosage concentration controls the C / N ratio to be 3-5:1.

[0102] The water distribution is preferably carried out by perforated pipes, with a perforation diameter of 5 to 10 mm and a perforation spacing of 100 to 200 mm.

[0103] The filter material used in the filtration is quartz sand; the particle size of the quartz sand is 3-5 mm, and the filter layer thickness is 200 mm.

[0104] During aerobic treatment, the filler used in the aerobic zone is made of polyurethane sponge; the density of the filler is 50-60% V / V; the wind pressure in the air supply zone is preferably 50-1000 Pa, more preferably 60-700 Pa; and the nitrification liquid reflux ratio is 2.0-3.0:1.

[0105] When sludge sedimentation is returned for clean water discharge treatment, the flow velocity in the sedimentation zone is 0.3-0.4 m / h; the sludge return ratio is 35-40%.

[0106] In the present invention, the COD- and nitrogen-containing organic wastewater to be treated includes one or more COD- and nitrogen-containing organic wastewaters generated in towns, rural areas, agglomeration areas and industries.

[0107] In order to further illustrate the present invention, an integrated device and method for biological treatment of nitrogen-containing organic wastewater by A / O tower provided by the present invention are described in detail below in combination with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0108] Example 1

[0109] (I) Overview: 1 Treatment object: rural domestic sewage; 2 Treatment scale: 30t / d; 3 Equipment name: A / O tower nitrogen-containing organic sewage treatment integrated machine as described in the above technical solution; 4 Equipment treatment process: the integrated machine is equipped with five processes: anoxic (A), lifting water distribution, filtration, three-phase contact aerobic (O), sludge sedimentation return and clear water discharge;

[0110] (II) Main technical parameters:

[0111] 1 Anoxic (A) pool parameters: residence time 4 hours, denitrification carbon source dosage ratio C / N 3-5; anoxic sludge concentration 15-30% V / V, dissolved oxygen 0.2-0.6 mg / l, sludge stirring using hydraulic stirring;

[0112] 2. Improve water distribution parameters and increase flow rate by 5m 3 / h, head 10m, power 0.75KW; water distributor: perforated pipe water distribution, perforation diameter 5mm, perforation spacing 100mm, water distributor height 200mm from the lower filter layer;

[0113] 3. Filter layer parameters: filter material: quartz sand, particle size: 3-5mm, filter layer thickness: 200mm;

[0114] 4 Three-phase contact aerobic (O) parameters: residence time 8 hours, biological filler material polyurethane sponge, filler installation density 55% (V / V), low-pressure fan pressure 60Pa, air volume 5000m 3 / h, power 0.38KW, nitration liquid reflux ratio 3:1;

[0115] 5. Sedimentation tank parameters: flow velocity in sedimentation zone 0.4m / h, sludge return ratio 35%;

[0116] (III) Treatment effect (average of laboratory testing statistics for one month)

[0117] Raw water before treatment: COD96.2mg / l, ammonia nitrogen 38.1mg / l, total nitrogen 45.6mg / l, total phosphorus 2.23mg / l;

[0118] Drainage after treatment: COD 38.7 mg / l, removal rate 59.77%; ammonia nitrogen 4.24 mg / l, removal rate 88.87%; total nitrogen 12.6 mg / l, removal rate 72.37%; total phosphorus 0.88 mg / l, removal rate 60.54%;.

[0119] Rural Domestic Wastewater Discharge Standard (no national standard, scope of each province and city): COD 30-80 mg / l, ammonia nitrogen 1.5-15 mg / l, total nitrogen 15-20 mg / l, total phosphorus 0.30-2 mg / l;

[0120] Odor emission test results from the top of the cylinder: odor concentration is 16 (dimensionless), which is better than the Class II area of ​​the "Emission Standard of Odor Pollutants", and the odor concentration limit is 20 (dimensionless) standard.

[0121] Embodiment 2:

[0122] (I) Overview: 1 Treatment object: dairy processing wastewater; 2 Treatment scale: 20t / d; 3 Equipment name: A / O tower nitrogen-containing organic wastewater treatment integrated machine as described in the above technical solution; 4 Equipment treatment process: the integrated machine is equipped with five processes: anoxic (A), lifting water distribution, filtration, three-phase contact aerobic (O), sludge sedimentation return and clear water discharge;

[0123] (II) Main technical parameters:

[0124] 1. Anoxic (A) pool parameters: residence time 6 hours, denitrification carbon source dosage ratio C / N 3-5; anoxic bacteria sludge concentration 20-30% V / V, dissolved oxygen 0.2-0.4 mg / l, sludge stirring adopts hydraulic stirring.

[0125] 2. Improve water distribution parameters and increase flow rate by 5m 3 / h, head 10m, power 0.75KW; water distributor: perforated pipe water distribution, perforation diameter 5mm, perforation spacing 100mm, the vertical height of the outlet of the water distributor from the lower filter layer is 200mm;

[0126] 3. Filter layer parameters: filter material is quartz sand, particle size is 3-5mm, filter layer thickness is 200mm;

[0127] 4. Three-phase contact aerobic (O) parameters: residence time 12hr, biological filler material polyurethane sponge, filler installation density 55% (V / V), low-pressure fan pressure 60Pa, air volume 5000m 3 / h, power 0.38KW, nitration liquid reflux ratio 3:1;

[0128] 5. Sedimentation tank parameters: flow velocity in sedimentation zone 0.30m / h, sludge return ratio 40%;

[0129] (III) Treatment effect (average of laboratory testing statistics for one month)

[0130] Raw water before treatment: COD510.6mg / l, ammonia nitrogen 66.2mg / l, total nitrogen 67.5mg / l, total phosphorus 2.10mg / l;

[0131] After treatment, the drainage water: COD 89.4 mg / l, removal rate 82.50%; ammonia nitrogen 12.4 mg / l, removal rate 81.3%; total nitrogen 20.2 mg / l, removal rate 70.1%; total phosphorus 0.82 mg / l, removal rate 61.0786i%;

[0132] "Comprehensive Wastewater Discharge Standard" (GB8978-1996) first-level standard: COD100mg / l, ammonia nitrogen 15mg / l, total nitrogen 22.7mg / l, phosphate 0.30mg / l;

[0133] Odor emission test results from the top of the cylinder: odor concentration is 16 (dimensionless), which is better than the Class II area of ​​the "Emission Standard of Odor Pollutants", and the odor concentration limit is 20 (dimensionless) standard.

[0134] Embodiment 3:

[0135] (I) Overview: 1. Treatment object: urban industrial and domestic comprehensive sewage; 2. Treatment scale: 10,000 t / d; 3. Equipment name: three-phase contact A / O tower as described in the above technical solution; 4. Equipment treatment process: the A / O tower is equipped with four processes: anoxic (A), lifting and water distribution, filtration, and three-phase contact aerobic (O);

[0136] (II) Main technical parameters:

[0137] 1. Anoxic (A) pool parameters: residence time 3 hours, denitrification carbon source dosage ratio C / N 3-5; anoxic bacteria sludge concentration 20-30% V / V, dissolved oxygen 0.2-0.6 mg / l, sludge mixing using 4 submersible mixers.

[0138] 2. Increase the water distribution area parameters and increase the pump flow rate to 270m 3 / h, 2 units, head 14m, single unit power 15KW; water distributor: perforated pipe water distribution, perforation diameter 10mm, perforation spacing 200mm, water distributor height 500mm from the lower filter layer;

[0139] 3. Filter layer parameters: filter material is quartz sand, particle size is 3-5mm, filter layer thickness is 200mm;

[0140] 4. Three-phase contact aerobic (O) parameters: residence time 9 hours, biological filler material polyurethane sponge, filler installation density 55% (V / V), 5 low-pressure fans, wind pressure 180Pa, air volume 10000m 3 / h, single unit power 0.75KW, nitration liquid reflux ratio 2.5:1;

[0141] 5. Sedimentation tank parameters: flow velocity in sedimentation zone 0.40m / h, sludge return ratio 40%;

[0142] (III) Treatment effect (average of laboratory testing statistics for one month)

[0143] Raw water before treatment: COD 114.12 mg / l, ammonia nitrogen 11.38 mg / l, total nitrogen 41.73 mg / l, total phosphorus 0.87 mg / l;

[0144] Drainage after treatment: COD 56.8 mg / l, removal rate 82.50%; ammonia nitrogen 4.84 mg / l, removal rate 74.43%; total nitrogen 9.16 mg / l, removal rate 78.05%; total phosphorus 0.52 mg / l, removal rate 40.02%;

[0145] "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" (GB18918-2002) Level A standard: COD60mg / l, ammonia nitrogen 5mg / l, total nitrogen 15mg / l, total phosphorus 2.0mg / l;

[0146] Odor emission test results from the top of the cylinder: odor concentration is 16 (dimensionless), which is better than the Class II area of ​​the "Emission Standard of Odor Pollutants", and the odor concentration limit is 20 (dimensionless) standard.

[0147] It can be seen from the above embodiments that the present invention provides an integrated device for biological treatment of COD and nitrogen-containing organic sewage in an A / O tower, comprising a cylinder; a water distribution area, a filtration area, a three-phase contact aerobic area, a nitrification liquid reflux discharge area and an anoxic area are arranged in sequence from top to bottom in the cylinder; the three-phase contact aerobic area is a normal-pressure high-oxygen biofilm filler area in a non-water accumulation area; a sewage inlet is arranged in the anoxic area; the water outlet of the anoxic area is connected to the water inlet of the water distribution area. The device integrates water distribution, filtration, three-phase contact aerobic, nitrification liquid reflux discharge and anoxic, saving floor space. The device has a high pollutant removal load per unit volume. The aerobic zone can synergistically treat the odor generated in the anoxic zone; the COD, ammonia nitrogen and total nitrogen removal rates are high.

[0148] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An integrated device for biological treatment of COD and nitrogen-containing organic wastewater by A / O tower, characterized in that: Including a cylinder; The cylinder is provided with a water distribution area, a filtration area, a three-phase contact aerobic area, a nitrification liquid reflux discharge area and anoxic area in sequence from top to bottom; The three-phase contact aerobic zone is a normal pressure high oxygen biofilm filler zone in a non-waterlogged area; A sewage inlet disposed in the anoxic zone; The water outlet of the anoxic zone is communicated with the water inlet of the water distribution zone; The three-phase contact aerobic zone includes a cyclonic air supply zone and an aerobic zone arranged directly above the cyclonic air supply zone; A low-pressure fan is provided on the cylinder wall of the cyclone air supply zone to provide low-pressure air to the cyclone air supply zone through an air inlet; The cyclone air supply area is in communication with the nitration liquid reflux discharge area; The device also includes a sedimentation clean water discharge unit; the sedimentation clean water discharge unit is provided with a sludge discharge port and a sludge discharge pipe connected to the discharge port; The sludge discharge pipe is provided with an excess sludge discharge port and a return sludge control valve; the return sludge control valve transports the return sludge and the sewage treated in the anoxic zone to the water distribution zone; The sedimentation water discharge unit is arranged inside the cylinder, between the nitrification liquid reflux discharge area and the anoxic area; or arranged outside the cylinder; Part of the nitrification liquid in the nitrification liquid reflux discharge area is discharged into the sedimentation clear water discharge unit; If the sedimentation water discharge unit is arranged outside the cylinder; The nitrification liquid reflux discharge area in the cylinder includes a nitrification liquid collection tank; A nitrification liquid discharge port and an exhaust hole are arranged at the bottom of the nitrification liquid collecting tank; the nitrification liquid discharge port is connected to a nitrification liquid guide pipe (17-2); The exhaust hole discharges the gas generated in the anoxic zone to the cyclone gas supply zone; and a nitrification liquid diversion well connected to the nitrification liquid diversion pipe, wherein a nitrification liquid reflux port and a nitrification liquid discharge port are provided at the lower part of the nitrification liquid diversion well; The nitrification liquid reflux port is in communication with the anoxic zone; the nitrification liquid discharge port is connected to the water inlet of the sedimentation clean water discharge unit located outside the cylinder through a pipeline; If the sedimentation clean water discharge unit is arranged in the cylinder, the nitrification liquid reflux discharge area in the cylinder includes a nitrification liquid collection tank; An exhaust-nitrification liquid guide pipe (17-1) and a central guide tube (19-1) arranged at the bottom of the nitrification liquid collection tank; The exhaust-nitrification liquid guide pipe discharges the gas in the anoxic zone to the cyclone gas supply zone and directs part of the nitrification liquid into the sedimentation clean water discharge unit through the central guide tube; Another part of the nitrification liquid in the nitrification liquid reflux discharge area flows back to the anoxic area through the exhaust gas-nitrification liquid guide pipe (17-1) passing through the sedimentation clean water discharge unit.

2. The integrated device for biological treatment of COD and nitrogen-containing organic wastewater by A / O tower according to claim 1, characterized in that: The filter area is a quartz sand, ordinary sand, granular activated carbon filter material particle filter layer, mesh filter plate or porous filter plate with a particle size of 3 to 50 mm and a thickness of 50 to 300 mm.

3. The integrated device for biological treatment of COD and nitrogen-containing organic wastewater by A / O tower according to claim 1, characterized in that: If the sedimentation clean water discharge unit is arranged in the cylinder, the inner wall of the cylinder of the sedimentation clean water discharge unit is provided with an annular overflow groove; A clean water discharge port is arranged on the outer wall of the cylinder corresponding to the annular overflow groove.

4. A method for treating COD-containing and nitrogen-containing organic wastewater using the integrated device for biological treatment of COD-containing and nitrogen-containing organic wastewater by A / O tower according to any one of claims 1 to 3, comprising the following steps: The COD and nitrogen-containing organic wastewater to be treated is sent to the anoxic zone for treatment, and the effluent is lifted and transported for distribution, and then filtered, aerobic treated, nitrified liquid refluxed and sludge sedimented, and discharged as clean water to obtain treated wastewater.

5. The method according to claim 4, characterized in that During anoxic treatment, the concentration of anoxic bacteria sludge is 15-30% V / V; the dissolved oxygen concentration is 0.2-0.6 mg / L; the residence time is 3-8 hours, and the denitrification carbon source dosage is controlled to have a C / N ratio of 3-5:1; During aerobic treatment, the density of the filler used in the aerobic zone is 50-60% V / V; the wind pressure in the air supply zone is 50-1000 Pa; and the reflux ratio of the nitrifying liquid is 2.0-3.0:

1.

6. The method according to claim 4, characterized in that The COD- and nitrogen-containing organic wastewater to be treated includes one or more COD- and nitrogen-containing organic wastewaters generated in towns, rural areas, agglomeration areas and industries.

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