A sewage deep treatment system and process

Abstract

The present invention discloses a sewage deep treatment system and process, which is characterized by: after the secondary treatment of the Baileke process section, it includes a water level lifting pool, a biological contact oxidation pool, a magnetic coagulation clarification pool, a disinfection contact pool, a tailwater well, a sludge storage pool and a sludge concentration and dehydration room. The present invention adopts a biological contact oxidation pool, which can effectively remove organic pollutants in sewage. The filler in the pool has a large specific surface area, good oxygenation conditions, a high volumetric load, and a strong adaptability to sudden changes in water quality and quantity. There is no sludge expansion problem, the operation and management are simple, there is no sludge reflux, and it is easy to cultivate bacteria and domesticate; magnetic powder is added to the magnetic coagulation clarification pool, the magnetic powder particles are tiny and have a high density, so that the colloidal particles in the water and the magnetic powder particles are easily collided and destabilized to form flocs, which greatly improves the removal efficiency and sedimentation speed of suspended matter, and is very suitable for deep treatment for removing TP and SS. The SS, TP, TN, NH3-N, COD, and BOD5 of the effluent of the magnetic coagulation clarification pool can all reach the Class A standard for discharge.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a sewage deep treatment system, process and system. Background Art

[0002] At present, some urban sewage treatment plants adopt the Biolake process, which is equipped with anaerobic tanks, aeration tanks, sedimentation tanks, and stabilization tanks. It has the functions of biological nitrogen removal and phosphorus removal. The actual effluent meets the Level B standard requirements of the "Pollutant Discharge Standard for Urban Sewage Treatment Plants" GB18918-2002, but cannot stably meet the Level A standard requirements of the "Pollutant Discharge Standard for Urban Sewage Treatment Plants" GB18918-2002. The following is a summary of the effluent water quality and discharge standards of a sewage treatment plant's existing process, as shown in Table 3-4.

[0003] Table 3-4 Summary of effluent quality and discharge standards of existing sewage treatment plants

[0004]

[0005] The above data show that after secondary treatment of urban sewage, the current effluent water quality can meet the Class B standard, and some water quality indicators can meet the Class A standard; however, due to the imbalance of the C:N ratio of the influent water quality and insufficient depth of process treatment, the BOD5, SS, NH3-N, TP and other indicators are all difficult to reach the Class A standard to varying degrees, among which TP and SS are mainly difficult to meet the standard. Therefore, although most of the suspended solids and organic matter are removed, there will still be a small amount of difficult-to-biodegrade organic matter, nitrogen and phosphorus compounds, unprecipitated solid particles, pathogenic microorganisms, inorganic salts and other pollutants.

[0006] Therefore, in order to achieve the effluent quality in accordance with the discharge requirements of Class A of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants GB18918-2002, it is necessary to carry out treatment and upgrading (i.e. deep treatment or tertiary treatment), re-treat the residual pollutants in the secondary treatment effluent, and remove the difficult-to-degrade organic matter, soluble inorganic nutrients (nitrogen, phosphorus) and suspended solids. The selected sewage deep treatment process needs to have a certain removal efficiency for the main indicators such as SS and TP. Summary of the invention

[0007] In order to solve the problem that the effluent quality of the above-mentioned existing sewage treatment Biolake process still contains a small amount of difficult-to-biodegrade organic matter, nitrogen and phosphorus compounds, unprecipitated solid particles, pathogenic microorganisms, inorganic salts and other pollutants, and the indicators such as BOD5, SS, NH3-N, TP have different degrees of probability of being difficult to reach the Class A standard, among which TP and SS are the main problems that are difficult to reach the standard, the present invention provides a sewage deep treatment system and process.

[0008] In order to achieve the above object, the present invention provides a sewage deep treatment system, which is characterized by comprising a water level lifting tank, a biological contact oxidation tank, a magnetic coagulation clarification tank, a disinfection contact tank, a tailwater well, a sludge storage tank and a sludge concentration and dehydration machine room;

[0009] The water level lifting tank is connected to the secondary sewage treatment system of the Biolake process section, and is provided with a submersible axial flow pump inside, which is used to lift the effluent from the secondary treatment of the Biolake process section to the biological contact oxidation tank;

[0010] The biological contact oxidation pool is connected to the water level lifting pool, and includes a first aerobic section, an anoxic section, and a second aerobic section that are connected in sequence. Suspended fillers are added into the biological contact oxidation pool, and the fillers are covered with microbial biofilms. The microbial biofilms in the anoxic section contain benzene ring and heterocyclic degradation bacteria, which are used to degrade COD and SS pollutants in sewage. The microbial biofilms in the first aerobic section and the second aerobic section contain sugars, organic acids, hydrocarbons, and other organic matter degradation bacteria, which are used to degrade COD, ammonia nitrogen, total nitrogen, chromaticity, and SS pollutants in sewage. Aeration blowers are provided at the sides of the first aerobic section and the second aerobic section, and perforated pipe aeration is provided at the bottom to provide oxygen to the microorganisms on the biofilm. After the biofilm grows to a certain thickness, the microorganisms on the filler will undergo anaerobic metabolism due to lack of oxygen, and the generated gas and the flushing effect formed by aeration will cause the biofilm to fall off and promote the growth of new biofilms. A low-speed submersible flow propeller is provided in the anoxic section to allow sewage to flow through the microbial biofilm at a certain flow rate;

[0011] The magnetic coagulation clarification tank is arranged in the clarification tank room, connected to the biological contact oxidation tank, and includes a coagulation reaction zone, a magnetic powder reaction zone, a flocculation reaction zone and a magnetic coagulation zone connected in sequence; the coagulation reaction zone is provided with two reaction tanks;

[0012] The coagulation reaction zone is doped with PAC coagulant and is internally provided with a type I vertical reaction tank agitator;

[0013] The magnetic powder reaction zone is doped with magnetic powder and is internally provided with a type II vertical reaction tank agitator;

[0014] The flocculation reaction zone is doped with PAM coagulant, and a type III vertical reaction tank agitator is provided inside;

[0015] The magnetic coagulation zone is provided with a plurality of inclined tubes at the top and a sludge settling chamber at the bottom. The flocs formed in the sewage in the magnetic coagulation zone settle on the inclined tube wall by gravity and slide into the sludge settling chamber at the bottom of the pool, so that the flocs can be separated from the water. A central transmission scraper is provided above the sludge settling chamber to prevent the deposition of magnetic powder and sludge at the bottom and facilitate better reflux.

[0016] A sludge outlet pipe is provided on the side wall of the sludge settling chamber, and the sludge outlet pipe is connected to the magnetic powder reaction zone through a sludge return pump and a sludge return pipe. The sludge return pump is provided with 1 to 2 pieces, and the sludge outlet pipe is connected to the high shear machine through a residual sludge pump and a residual sludge pipe. The sludge outlet of the high shear machine is connected to a magnetic separator, and the sludge outlet of the magnetic separator is connected to a sludge storage tank. The magnetic powder separated in the magnetic separator is returned to the magnetic powder reaction zone through a magnetic powder recovery pipe. The sludge storage tank is used to store the sludge generated during the sewage treatment process and pump it to the sludge concentration and dehydration room. A submersible mixer is provided inside the sludge storage tank to prevent sludge deposition;

[0017] The sludge thickening and dehydration room is provided with a belt-type thickening and dehydration integrated machine for thickening and dehydrating the sludge;

[0018] The upper part of the magnetic coagulation zone is connected to a disinfection contact pool, in which a number of low-voltage, high-intensity, solid-state mercury alloy ultraviolet lamps and electronic ballasts are arranged;

[0019] The tailwater well is connected to the disinfection contact tank and is used to store disinfected and purified water and discharge it to the outside through a drainage pipe;

[0020] The submersible axial flow pump, aeration blower, low-speed submersible flow propeller, type I vertical reaction tank agitator, type II vertical reaction tank agitator, type III vertical reaction tank agitator, central transmission scraper, sludge return pump, residual sludge pump, high shear machine, magnetic separator, submersible mixer, belt-type concentrator and dehydrator, and electronic ballast are all connected to the PLC control system.

[0021] As a further improvement of this technology, it also includes a PAM dosing room, a coagulant storage tank, a carbon source storage tank and a sodium hypochlorite storage tank;

[0022] The PAM dosing room is used for preparing, storing and adding PAM coagulant, and is located next to the flocculation reaction zone in the clarification tank, and is connected to the flocculation reaction zone through a dosing pump and a dosing pipe;

[0023] The coagulant storage tank, the carbon source storage tank and the sodium hypochlorite storage tank are all arranged outside the clarification tank, and are used to store PAC coagulant, carbon source and sodium hypochlorite respectively. The coagulant storage tank is connected to the coagulation reaction zone through the coagulant diaphragm metering pump and the first infusion pipe, the carbon source storage tank is connected to the anoxic section through the carbon source diaphragm metering pump and the second infusion pipe, and the sodium hypochlorite storage tank is connected to the water inlet end of the disinfection contact tank through the sodium hypochlorite diaphragm metering pump and the third infusion pipe;

[0024] The dosing pump, the coagulant diaphragm metering pump, the carbon source diaphragm metering pump and the sodium hypochlorite diaphragm metering pump are all connected to the PLC control system.

[0025] As a further improvement of the present technology, the particle size of the magnetic powder is set to 90-110 μm; the average surface load of the inclined tube is set to 14.7 m / h, and the peak surface load is set to 19.1 m / h.

[0026] As a further improvement of this technology, the suspended filler adopts braided filler, the biosolids concentration in the pool is set to 5-10g / l, and the volume load can reach 2.0-3.0kgBOD 5 / m 3 .d.

[0027] As a further improvement of the present technology, a carbon source is added into the anoxic section, and the carbon source is set to sodium acetate to help denitrification.

[0028] As a further improvement of the present technology, sodium hypochlorite disinfectant is added to the water inlet of the disinfection contact pool to enhance the removal of Escherichia coli.

[0029] As a further improvement of the present technology, the outer side of the solid mercury alloy ultraviolet lamp is provided with an automatically cleanable ultraviolet lamp sleeve for cleaning the dirt film adsorbed on the sleeve wall, ensuring that the transmission of ultraviolet light intensity is not reduced and ensuring continuous sterilization function.

[0030] The present invention also provides a treatment process of the above sewage deep treatment system, which is characterized by comprising the following steps:

[0031] S1, effluent lifting: the effluent after secondary treatment in the Biolek process section is discharged into the intermediate water level lifting tank and then pumped into the biological contact oxidation tank through a submersible axial flow pump;

[0032] S2. Enhanced biochemical treatment: The sewage entering the biological contact oxidation pool passes through the first aerobic section, the anoxic section, and the second aerobic section in turn. The sewage retention time in the three treatment sections is 1h, 1.25h, and 0.25h, respectively. Through the action of the low-speed submersible flow propeller, the sewage flows through the biofilm covered on the bottom filler of the pool at a certain flow rate. The sewage is in extensive contact with the biofilm, and the organic pollutants in the sewage can be finally removed under the action of the metabolism of the microorganisms on the biofilm.

[0033] S3, magnetic coagulation sedimentation process: the effluent purified in step S2 enters the magnetic coagulation clarification tank, and passes through the coagulation reaction zone, magnetic powder reaction zone, flocculation reaction zone and magnetic coagulation zone in sequence. PAC coagulant, magnetic powder and PAM coagulant aid are added into the coagulation reaction zone, magnetic powder reaction zone and flocculation reaction zone respectively. The dosage of PAC coagulant is set to 50-80 mg / l, the dosage of PAM coagulant aid is set to 0.5-0.8 mg / l, and the sewage residence time in the coagulation reaction zone, magnetic powder reaction zone and flocculation reaction zone is 2.5-3.0 mg / l. The stirring time is set to 10 minutes. At the same time, the agitators of the type I vertical reaction tank, the type II vertical reaction tank, and the type III vertical reaction tank in the pool stir at a speed of 200-300r / min. The sewage retention time in the magnetic coagulation zone is set to 30 minutes. The magnetic coagulation clarification tank mainly removes TP and SS in the sewage, and also has a partial removal effect on COD and BOD5. The effluent SS, TP, TN, NH3-N, COD, and BOD5 of the magnetic coagulation zone 34 can all meet the Class A discharge standard.

[0034] S4, sludge return process: the flocs formed in the sewage entering the magnetic coagulation zone in step S3 settle on the upper inclined pipe wall by gravity, and slide into the sludge settling chamber at the bottom of the pool along the inclined pipe wall, so that the flocs can be separated from the water. The sludge in the sludge settling chamber returns to the flocculation reaction zone through the sludge outlet pipe, the sludge return pump, and the sludge return pipe to continue to participate in the flocculation reaction. The PAC coagulant, magnetic powder, and PAM coagulant aid returned with the sludge can play a role again, which helps to reduce the dosage of the PAC coagulant, magnetic powder, and PAM coagulant aid;

[0035] The frequency of the sludge return pump 35 is set to 0-50HZ, and the return ratio of the sludge is 8%-12% of the water intake;

[0036] S5. Regular sludge discharge process: The residual sludge pump regularly pumps the residual sludge in the magnetic coagulation area into the high shear machine through the residual sludge pipe. The sludge discharge ratio is set to 2% of the water intake. After being crushed by the high shear machine, it enters the magnetic separator. The separated magnetic powder returns to the magnetic powder reaction area to continue to participate in the reaction, which can reduce the amount of magnetic powder added. The residual sludge from the magnetic separator is pumped into the sludge storage tank;

[0037] S6. Disinfection process: The effluent from the magnetic coagulation area enters the disinfection contact pool, and sodium hypochlorite disinfectant is added to the water inlet of the disinfection contact pool to remove E. coli. Then, the water is sterilized by the strong sterilization of C-band ultraviolet light emitted by a low-pressure, high-intensity, solid-state mercury alloy ultraviolet lamp, which can kill various bacteria, viruses, parasites, algae and other pathogens in the water. The fecal coliform count is less than 1,000 / L, reaching the Class A standard.

[0038] S7, tailwater well water discharge: the water sterilized and disinfected in step S6 is discharged into the tailwater well and discharged to the outside through the drainage pipe;

[0039] S8, sludge concentration and dehydration process: the sludge in the sludge storage tank in step S5 is pumped into the sludge concentration and dehydration room, dehydrated and concentrated to a moisture content of less than 80% by a belt-type concentration and dehydration integrated machine, and then transported to the sludge deep treatment workshop.

[0040] As a further improvement of the present technology, sodium acetate is added as a supplementary carbon source in the anoxic section in step S2 as needed to assist denitrification and reduce the total nitrogen index in the sewage.

[0041] As a further improvement of the present technology, the UV lamp sleeve arranged outside the UV lamp in step S6 can automatically and regularly clean the dirt film adsorbed on the sleeve wall to ensure that the transmission of UV light intensity is not reduced and to ensure continuous sterilization function.

[0042] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a biological contact oxidation pond, which can effectively remove organic pollutants in sewage. Since the filler in the pond has a large specific surface area and good oxygenation conditions, it has a high volume load and occupies a small area; since the biological solids per unit volume in the biological contact oxidation pond are high and the water flow is completely mixed, it has a strong adaptability to sudden changes in water quality and quantity; since the amount of residual sludge in the biological contact oxidation pond is small, there is no sludge expansion problem, the operation and management are simple, there is no sludge reflux, and it is easy to cultivate bacteria; 2. This The invention adopts a magnetic coagulation clarification tank, in which magnetic powder is added. The magnetic powder particles are tiny and serve as precipitation nuclei, so that the colloidal particles in the water and the magnetic powder particles can easily collide and destabilize to form flocs, and the removal efficiency of suspended matter is greatly improved; at the same time, due to the high density of the magnetic powder, the density of the flocs is much greater than that of conventional coagulation flocs, thereby greatly improving the sedimentation speed; the magnetic coagulation sedimentation process has low operating costs and small footprint, and is very suitable for deep treatment of TP and SS removal. The SS, TP, TN, NH3-N, COD, and BOD5 of the effluent from the magnetic coagulation tank can reach 3. The magnetic coagulation and sedimentation process of the present invention is provided with sludge return, and the PAC coagulant, magnetic powder, and PAM coagulant can play a role again, which helps to reduce the dosage of PAC coagulant, magnetic powder, and PAM coagulant, saving costs; there is no magnetic separator, so that the magnetic powder in the remaining sludge can be returned to the magnetic powder reaction zone, reducing the dosage of magnetic powder, greatly saving the cost of sewage deep treatment; 4. The present invention adopts the strong sterilization and disinfection of C-band ultraviolet light emitted by low-pressure and high-strength solid mercury alloy ultraviolet lamp, and ultraviolet C has strong sterilization and disinfection effect on bacteria and viruses. The sterilization effect is generally within one second, and it can efficiently kill almost all bacteria and viruses, and can effectively kill some parasites that are extremely harmful to humans but cannot be or cannot be effectively killed by chlorine or even ozone (such as cryptosporidium, Giardia, etc.); UV C sterilization has no secondary pollution, and the operation is safe and reliable; 5. The present invention adds sodium hypochlorite disinfectant at the water inlet end of the disinfection contact tank to remove Escherichia coli, so that the tail water after disinfection meets the Class A discharge standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The process roadmap of the embodiment of the present invention is shown in FIG.

[0044] Figure 2 It is a schematic diagram of the structure of a magnetic coagulation clarification tank according to an embodiment of the present invention.

[0045] In the figure: 1, water level lifting tank, 2, biological contact oxidation tank, 21, first aerobic section, 22, anoxic section, 23, second aerobic section, 3, magnetic coagulation clarification tank, 31, coagulation reaction zone, 311, type I vertical reaction tank agitator, 32, magnetic powder reaction zone, 321, type II vertical reaction tank agitator, 33, flocculation reaction zone, 331, type III vertical reaction tank agitator, 34, magnetic coagulation zone, 341, central drive scraper, 342, inclined pipe, 343, sludge settling chamber, 344, sludge outlet pipe, 345, sludge return pipe, 346, residual sludge pipe, 35, sludge return pump, 36, residual sludge pump, 37, high shear machine, 38, magnetic separator, 39, magnetic powder recovery pipe, 4, contact disinfection tank, 5, tailwater well, 6, sludge storage tank, 7, sludge concentration and dehydration room. DETAILED DESCRIPTION

[0046] The present invention is described in detail below in conjunction with the examples. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form.

[0047] like Figure 1 , 2 As shown, the sewage deep treatment system of the first embodiment of the present invention comprises a water level lifting tank 1, a biological contact oxidation tank 2, a magnetic coagulation clarification tank 3, a disinfection contact tank 4, a tailwater well 5, a sludge storage tank 6 and a sludge concentration and dehydration machine room 7;

[0048] The water level lifting tank 1 is connected to the secondary sewage treatment system of the Biolake process section, and is provided with a submersible axial flow pump for lifting the effluent from the secondary treatment of the Biolake process section to the biological contact oxidation tank 2;

[0049] The biological contact oxidation pool 2 is connected to the water level lifting pool 1, and includes a first aerobic section 21, an anoxic section 22, and a second aerobic section 23 connected in sequence. Suspended fillers are added into the biological contact oxidation pool 2, and the fillers are covered with microbial biofilms. The microbial biofilms in the anoxic section 22 contain benzene ring and heterocyclic degradation bacteria, which are used to degrade COD and SS pollutants in the sewage. The microbial biofilms in the first aerobic section 21 and the second aerobic section 23 contain sugars, organic acids, hydrocarbons and other organic matter degradation bacteria, which are used to degrade COD, ammonia nitrogen, total nitrogen, chromaticity, SS pollutants, the first aerobic section 21 and the second aerobic section 23 are provided with an aeration blower at the side of the pool, and a perforated pipe aeration is provided at the bottom to provide oxygen to the microorganisms on the biofilm. After the biofilm grows to a certain thickness, the microorganisms on the filler will undergo anaerobic metabolism due to lack of oxygen. The generated gas and the flushing effect formed by aeration will cause the biofilm to fall off and promote the growth of new biofilms. A low-speed submersible flow propeller is provided in the anoxic section 22 to allow the sewage to flow through the microbial biofilm at a certain flow rate;

[0050] The magnetic coagulation clarification tank 3 is arranged in the clarification tank room, connected to the biological contact oxidation tank 2, and includes a coagulation reaction zone 31, a magnetic powder reaction zone 32, a flocculation reaction zone 33 and a magnetic coagulation zone 34 connected in sequence; the coagulation reaction zone 31 is provided with two reaction tanks;

[0051] The coagulation reaction zone 31 is doped with PAC coagulant and is provided with a type I vertical reaction tank agitator 311;

[0052] The magnetic powder reaction zone 32 is doped with magnetic powder and is provided with a type II vertical reaction tank agitator 321;

[0053] The flocculation reaction zone 33 is doped with PAM coagulant, and a type III vertical reaction tank agitator 331 is provided inside;

[0054] A plurality of inclined tubes 342 are provided on the upper part of the magnetic coagulation zone 34, and a sludge settling chamber 343 is provided in the middle of the bottom. The flocs formed in the sewage in the magnetic coagulation zone 34 settle on the wall of the inclined tube 342 by gravity, and slide into the sludge settling chamber 343 at the bottom of the pool, so that the flocs can be separated from the water. A central transmission scraper 341 is provided above the sludge settling chamber 343 to prevent the deposition of magnetic powder and sludge at the bottom and facilitate better reflux.

[0055] A sludge outlet pipe 344 is provided on the side wall of the sludge settling chamber 343. The sludge outlet pipe 344 is connected to the magnetic powder reaction zone 32 through a sludge return pump 35 and a sludge return pipe 345. The sludge return pump 35 is provided with two pieces. The sludge outlet pipe 344 is connected to a high shear machine 37 through a residual sludge pump 36 and a residual sludge pipe 346. The sludge outlet of the high shear machine 37 is connected to a magnetic separator 38. The sludge outlet of the magnetic separator 38 is connected to a sludge storage tank 6. The magnetic powder separated in the magnetic separator 38 is returned to the magnetic powder reaction zone 32 through a magnetic powder recovery pipe 39. The sludge storage tank 6 is used to store the sludge generated during the sewage treatment process and pump it to the sludge concentration and dehydration machine room 7. A submersible mixer is provided inside the sludge storage tank 6 to prevent sludge deposition.

[0056] The sludge thickening and dehydrating room 7 is equipped with a belt-type thickening and dehydrating integrated machine for thickening and dehydrating the sludge;

[0057] The upper part of the magnetic coagulation area 34 is connected to the disinfection contact pool 4, which is equipped with 200 to 240 320W / low-voltage high-intensity solid mercury alloy ultraviolet lamps and electronic ballasts, and the power of the lamp tube reaches 83KW;

[0058] The tailwater well 5 is connected to the disinfection contact tank 4 and is used to store the disinfected and purified water and discharge it to the outside through the drainage pipe;

[0059] Submersible axial flow pump, aeration blower, low-speed submersible flow propeller, type I vertical reaction tank agitator 311, type II vertical reaction tank agitator 321, type III vertical reaction tank agitator 331, central drive scraper 341, sludge return pump 35, residual sludge pump 36, high shear machine 37, magnetic separator 38, submersible mixer, belt-type concentrator and dehydrator, and electronic ballast are all connected to the PLC control system.

[0060] The embodiment of the present invention also includes a PAM dosing room, a coagulant storage tank, a carbon source storage tank and a sodium hypochlorite storage tank;

[0061] The PAM dosing room is used for preparing, storing and adding PAM coagulant aids. It is located next to the flocculation reaction area in the clarification tank and is connected to the flocculation reaction area through a dosing pump and a dosing pipe.

[0062] The coagulant storage tank, the carbon source storage tank and the sodium hypochlorite storage tank are all arranged outside the clarification tank room, and are used to store PAC coagulant, carbon source and sodium hypochlorite respectively. The coagulant storage tank is connected with the coagulation reaction zone through the coagulant diaphragm metering pump and the first infusion pipe, and is used to add PAC coagulant to the coagulation reaction zone. The carbon source storage tank is connected with the anoxic section through the carbon source diaphragm metering pump and the second infusion pipe, and is used to add the carbon source to the anoxic section. The sodium hypochlorite storage tank is connected with the water inlet end of the disinfection contact tank through the sodium hypochlorite diaphragm metering pump and the third infusion pipe, and is used to add sodium hypochlorite to the water inlet end of the disinfection contact tank.

[0063] The dosing pump, the coagulant diaphragm metering pump, the carbon source diaphragm metering pump and the sodium hypochlorite diaphragm metering pump are all connected to the PLC control system.

[0064] The particle size of the magnetic powder is set to 90-110 μm; the average surface load of the inclined tube 342 above the magnetic coagulation zone is set to 14.7 m / h, and the peak surface load is set to 19.1 m / h.

[0065] As a preferred method, the suspended filler is braided filler, the biosolids concentration in the pool is set at 5-10 g / l, and the volume load can reach 2.0-3.0 kg BOD 5 / m 3 .d.

[0066] Preferably, a carbon source is added into the anoxic section 22, wherein the carbon source is sodium acetate to assist denitrification.

[0067] Preferably, sodium hypochlorite disinfectant is added to the water inlet of the disinfection contact pool 4 to enhance the removal of Escherichia coli and ensure that the effluent meets the Class A standard.

[0068] Preferably, the solid mercury alloy ultraviolet lamp is sheathed with an automatically cleanable ultraviolet lamp sleeve for cleaning the dirt film adsorbed on the sleeve wall, ensuring that the transmission of ultraviolet light intensity is not reduced and ensuring continuous sterilization function.

[0069] The second embodiment of the present invention further provides a treatment process of the first embodiment of the sewage deep treatment system, comprising the following steps:

[0070] S1, effluent lifting: the effluent after secondary treatment in the Biolek process section is discharged into the intermediate water level lifting tank 1, and then pumped into the biological contact oxidation tank 2 through a submersible axial flow pump;

[0071] S2. Enhanced biochemical treatment: The sewage entering the biological contact oxidation pond 2 passes through the first aerobic section 21, the anoxic section 22, and the second aerobic section 23 in sequence. The sewage retention time in the three treatment sections is 1h, 1.25h, and 0.25h, respectively. The sewage flows through the biofilm on the bottom filler of the pond at a certain flow rate through the low-speed submersible flow propeller. The sewage is in extensive contact with the biofilm. Under the metabolism of the microorganisms on the biofilm, the organic pollutants in the sewage can be finally removed.

[0072] S3, magnetic coagulation sedimentation process: the effluent purified in step S2 enters the magnetic coagulation clarification tank 3, and passes through the coagulation reaction zone 31, the magnetic powder reaction zone 32, the flocculation reaction zone 33 and the magnetic coagulation zone 34 in sequence. PAC coagulant, magnetic powder and PAM coagulant are added to the coagulation reaction zone 31, the magnetic powder reaction zone 32 and the flocculation reaction zone 33 respectively. The dosage of PAC coagulant is set to 50-80 mg / l, and the dosage of PAM coagulant is set to 0.5-0.8 mg / l. The sewage in the coagulation reaction zone 31, the magnetic powder reaction zone 32 and the flocculation reaction zone 34 is The retention time is set to 10 minutes. At the same time, the agitators 311 of the type I vertical reaction tank, 321 of the type II vertical reaction tank, and 331 of the type III vertical reaction tank are stirred at a speed of 200-300 r / min. The retention time of sewage in the magnetic coagulation zone 34 is set to 30 minutes. The magnetic coagulation clarification tank 3 mainly removes TP and SS in the sewage, and also has a partial removal effect on COD and BOD5. The effluent SS, TP, TN, NH3-N, COD, and BOD5 of the magnetic coagulation zone 34 can all meet the Class A standard.

[0073] S4, sludge return process: in step S3, the flocs formed in the sewage entering the magnetic coagulation zone 34 settle on the wall of the upper inclined tube 342 by gravity, and slide into the sludge settling chamber 343 at the bottom of the pool along the wall of the inclined tube 342, so that the flocs can be separated from the water. The sludge in the sludge settling chamber 343 returns to the flocculation reaction zone 33 through the sludge outlet pipe 344, the sludge return pump 35, and the sludge return pipe 345 to continue to participate in the flocculation reaction. The PAC coagulant, magnetic powder, and PAM coagulant aid returned with the sludge can play a role again, which helps to reduce the dosage of the PAC coagulant, magnetic powder, and PAM coagulant aid;

[0074] The frequency of the sludge return pump 35 is set to 0-50HZ, and the sludge return ratio is 8%-12% of the water inlet to maintain the balance of the sludge volume inside the tank;

[0075] S5, regular sludge discharge process: the residual sludge pump 36 regularly pumps the residual sludge in the magnetic coagulation area into the high shear machine 37 through the residual sludge pipe 346, and the sludge discharge ratio is set to 2% of the water inlet volume, which is used to remove the excess sludge and maintain the normal solid load in the tank. After being crushed by the high shear machine 37, it enters the magnetic separator 38, and the separated magnetic powder returns to the magnetic powder reaction area 32 to continue to participate in the reaction, which can reduce the amount of magnetic powder added. The residual sludge from the magnetic separator 38 is pumped into the sludge storage tank 6;

[0076] S6, disinfection process: the water from the magnetic coagulation area 34 enters the disinfection contact pool 4, and sodium hypochlorite disinfectant is added to the water inlet of the disinfection contact pool 4 to remove E. coli. Then, the water is sterilized by C-band ultraviolet light emitted by 200 to 240 320W / low-pressure, high-intensity, solid-state mercury alloy ultraviolet lamps, which can kill various bacteria, viruses, parasites, algae and other pathogens in the water. The fecal coliform count is less than 1000 / L, reaching the Class A standard.

[0077] S7, tailwater well water discharge: the water after sterilization and disinfection in step S6 is discharged into the tailwater well 5, and discharged to the outside through the drainage pipe;

[0078] S8, sludge concentration and dehydration process: the sludge in the sludge storage tank 6 in step S5 is pumped into the sludge concentration and dehydration room 7, and is dehydrated and concentrated to a moisture content of less than 80% by a belt-type concentration and dehydration integrated machine, and then transported to the sludge deep treatment workshop.

[0079] Preferably, sodium acetate is added to the anoxic section 22 in step S2 as required as a supplementary carbon source to assist denitrification and reduce the total nitrogen index in the sewage.

[0080] Preferably, the UV lamp sleeve arranged outside the UV lamp in step S6 can automatically and regularly clean the dirt film adsorbed on the sleeve wall to ensure that the transmission of UV light intensity is not reduced and the continuous sterilization function is guaranteed.

[0081] The following is a summary table of effluent water quality and discharge standards of Example 2 of the present invention:

[0082]

[0083]

[0084] It can be seen from the above table that the values ​​of the six treatment units in the effluent water quality of the second embodiment of the present invention are all lower than the first-level A discharge standard, and can 100% reach the first-level A discharge standard.

[0085] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A sewage deep treatment system, characterized by: It includes a water level lifting tank, a biological contact oxidation tank, a magnetic coagulation clarification tank, a disinfection contact tank, a tailwater well, a sludge storage tank and a sludge thickening and dehydration room; The water level lifting tank is connected to the secondary sewage treatment system of the Biolake process section, and is provided with a submersible axial flow pump inside, which is used to lift the effluent from the secondary treatment of the Biolake process section to the biological contact oxidation tank; The biological contact oxidation pool is connected to the water level lifting pool, and includes a first aerobic section, an anoxic section, and a second aerobic section connected in sequence. Suspended fillers are added into the biological contact oxidation pool, and the fillers are covered with microbial biofilms. The microbial biofilms in the anoxic section contain benzene ring and heterocyclic degradation bacteria, which are used to degrade COD and SS pollutants in sewage. The microbial biofilms in the first aerobic section and the second aerobic section contain sugars, organic acids, hydrocarbons, and other organic matter degradation bacteria, which are used to degrade COD, ammonia nitrogen, total nitrogen, chromaticity, and SS pollutants in sewage. Aeration blowers are provided at the sides of the first aerobic section and the second aerobic section, and perforated pipe aeration is provided at the bottom to provide oxygen to the microorganisms on the biofilm. After the biofilm grows to a certain thickness, the microorganisms on the filler will undergo anaerobic metabolism due to lack of oxygen, and the generated gas and the flushing effect formed by aeration will cause the biofilm to fall off and promote the growth of new biofilms. A low-speed submersible flow propeller is provided in the anoxic section to allow sewage to flow through the microbial biofilm at a certain flow rate; The magnetic coagulation clarification tank is arranged in the clarification tank room, connected to the biological contact oxidation tank, and includes a coagulation reaction zone, a magnetic powder reaction zone, a flocculation reaction zone and a magnetic coagulation zone connected in sequence; the coagulation reaction zone is provided with two reaction tanks; The coagulation reaction zone is doped with PAC coagulant and is internally provided with a type I vertical reaction tank agitator; The magnetic powder reaction zone is doped with magnetic powder and is internally provided with a type II vertical reaction tank agitator; The flocculation reaction zone is doped with PAM coagulant, and a type III vertical reaction tank agitator is provided inside; The magnetic coagulation zone is provided with a plurality of inclined tubes at the top and a sludge settling chamber at the bottom. The flocs formed in the sewage in the magnetic coagulation zone settle on the inclined tube wall by gravity and slide into the sludge settling chamber at the bottom of the pool, so that the flocs can be separated from the water. A central transmission scraper is provided above the sludge settling chamber to prevent the deposition of magnetic powder and sludge at the bottom and facilitate better reflux. A sludge outlet pipe is provided on the side wall of the sludge settling chamber, and the sludge outlet pipe is connected to the magnetic powder reaction zone through a sludge return pump and a sludge return pipe. The sludge return pump is provided with 1 to 2 pieces, and the sludge outlet pipe is connected to the high shear machine through a residual sludge pump and a residual sludge pipe. The sludge outlet of the high shear machine is connected to a magnetic separator, and the sludge outlet of the magnetic separator is connected to a sludge storage tank. The magnetic powder separated in the magnetic separator is returned to the magnetic powder reaction zone through a magnetic powder recovery pipe. The sludge storage tank is used to store the sludge generated during the sewage treatment process and pump it to the sludge concentration and dehydration room. A submersible mixer is provided inside the sludge storage tank to prevent sludge deposition; The sludge thickening and dehydration room is provided with a belt-type thickening and dehydration integrated machine for thickening and dehydrating the sludge; The upper part of the magnetic coagulation zone is connected to a disinfection contact pool, in which a number of low-voltage, high-strength, solid-state mercury alloy ultraviolet lamps and electronic ballasts are arranged; The tailwater well is connected to the disinfection contact tank and is used to store disinfected and purified water and discharge it to the outside through a drainage pipe; The submersible axial flow pump, aeration blower, low-speed submersible flow propeller, type I vertical reaction tank agitator, type II vertical reaction tank agitator, type III vertical reaction tank agitator, central transmission scraper, sludge return pump, residual sludge pump, high shear machine, magnetic separator, submersible mixer, belt-type concentrator and dehydrator, and electronic ballast are all connected to the PLC control system.

2. A sewage deep treatment system according to claim 1, characterized in that: It also includes a PAM dosing room, a coagulant storage tank, a carbon source storage tank, and a sodium hypochlorite storage tank; The PAM dosing room is used for preparing, storing and adding PAM coagulant, and is located next to the flocculation reaction zone in the clarification tank, and is connected to the flocculation reaction zone through a dosing pump and a dosing pipe; The coagulant storage tank, the carbon source storage tank and the sodium hypochlorite storage tank are all arranged outside the clarification tank, and are used to store PAC coagulant, carbon source and sodium hypochlorite respectively. The coagulant storage tank is connected to the coagulation reaction zone through the coagulant diaphragm metering pump and the first infusion pipe, the carbon source storage tank is connected to the anoxic section through the carbon source diaphragm metering pump and the second infusion pipe, and the sodium hypochlorite storage tank is connected to the water inlet end of the disinfection contact tank through the sodium hypochlorite diaphragm metering pump and the third infusion pipe; The dosing pump, the coagulant diaphragm metering pump, the carbon source diaphragm metering pump and the sodium hypochlorite diaphragm metering pump are all connected to the PLC control system.

3. A sewage deep treatment system according to claim 1, characterized in that: The magnetic powder particle size is set to 90-110 μm; the average surface load of the inclined tube is set to 14.7 m / h, and the peak surface load is set to 19.1 m / h.

4. A sewage deep treatment system according to claim 1, characterized in that: The suspended filler is a braided filler, the biosolids concentration in the pool is set to 5-10 g / l, and the volume load is 2.0-3.0 kg BOD5 / m 3 .d.

5. A sewage deep treatment system according to claim 2, characterized in that: A carbon source is added into the anoxic section, and the carbon source is set as sodium acetate to help denitrification.

6. A sewage deep treatment system according to claim 2, characterized in that: Sodium hypochlorite disinfectant is added to the water inlet end of the disinfection contact pool.

7. A sewage deep treatment system according to claim 1, characterized in that: The outer side of the mercury alloy ultraviolet lamp is provided with an automatic cleaning ultraviolet lamp sleeve for cleaning the dirt film adsorbed on the sleeve wall, ensuring that the transmission of ultraviolet light intensity is not reduced and the continuous sterilization function is guaranteed.

8. A treatment process of the sewage deep treatment system according to any one of claims 1 to 7, characterized in that The steps include: S1, effluent lifting: the effluent after secondary treatment in the Biolek process section is discharged into the intermediate water level lifting tank and then pumped into the biological contact oxidation tank through a submersible axial flow pump; S2. Enhanced biochemical treatment: The sewage entering the biological contact oxidation pool passes through the first aerobic section, the anoxic section, and the second aerobic section in turn. The sewage retention time in the three treatment sections is 1h, 1.25h, and 0.25h, respectively. Through the action of the low-speed submersible flow propeller, the sewage flows through the biofilm covered on the bottom filler of the pool at a certain flow rate. The sewage is in extensive contact with the biofilm, and the organic pollutants in the sewage are finally removed under the metabolism of the microorganisms on the biofilm. S3, magnetic coagulation sedimentation process: the effluent purified in step S2 enters the magnetic coagulation clarification tank, and passes through the coagulation reaction zone, magnetic powder reaction zone, flocculation reaction zone and magnetic coagulation zone in sequence. PAC coagulant, magnetic powder and PAM coagulant aid are added to the coagulation reaction zone, magnetic powder reaction zone and flocculation reaction zone respectively. The dosage of PAC coagulant is set to 50-80 mg / l, and the dosage of PAM coagulant aid is set to 0.5-0.8 mg / l. The sewage stays in the coagulation reaction zone, magnetic powder reaction zone and flocculation reaction zone for a period of 2-3 hours. The stirring time is set to 10 minutes. At the same time, the agitators of the type I vertical reaction tank, the type II vertical reaction tank, and the type III vertical reaction tank in the pool stir at a speed of 200-300r / min. The sewage retention time in the magnetic coagulation zone is set to 30 minutes. The magnetic coagulation clarification tank mainly removes TP and SS in the sewage, and also has a partial removal effect on COD and BOD5. The effluent SS, TP, TN, NH3-N, COD, and BOD5 in the magnetic coagulation zone all meet the Class A discharge standard. S4, sludge return process: the flocs formed in the sewage entering the magnetic coagulation zone in step S3 settle on the upper inclined pipe wall by gravity, and slide into the sludge settling chamber at the bottom of the pool along the inclined pipe wall, so that the flocs can be separated from the water. The sludge in the sludge settling chamber returns to the flocculation reaction zone through the sludge outlet pipe, the sludge return pump, and the sludge return pipe to continue to participate in the flocculation reaction. The PAC coagulant, magnetic powder, and PAM coagulant aid returned with the sludge can play a role again, which helps to reduce the dosage of the PAC coagulant, magnetic powder, and PAM coagulant aid; The frequency of the sludge return pump is set to 0-50HZ, and the sludge return ratio is 8%-12% of the water intake; S5. Regular sludge discharge process: The residual sludge pump regularly pumps the residual sludge in the magnetic coagulation area into the high shear machine through the residual sludge pipe. The sludge discharge ratio is set to 2% of the water intake. After being crushed by the high shear machine, it enters the magnetic separator. The separated magnetic powder returns to the magnetic powder reaction area to continue to participate in the reaction, which can reduce the amount of magnetic powder added. The residual sludge from the magnetic separator is pumped into the sludge storage tank; S6. Disinfection process: The effluent from the magnetic coagulation area enters the disinfection contact pool, and sodium hypochlorite disinfectant is added to the water inlet of the disinfection contact pool to remove E. coli. Then, the water is sterilized by the strong sterilization of C-band ultraviolet light emitted by a low-pressure, high-intensity, solid-state mercury alloy ultraviolet lamp, which can kill various bacteria, viruses, parasites, and algae in the water. The number of fecal coliform bacteria is less than 1,000 / L, reaching the Class A discharge standard; S7, tailwater well water discharge: the water sterilized and disinfected in step S6 is discharged into the tailwater well and discharged to the outside through the drainage pipe; S8, sludge concentration and dehydration process: The sludge in the sludge storage tank in step S5 is pumped into the sludge concentration and dehydration room, dehydrated and concentrated to a moisture content of less than 80% by a belt-type concentration and dehydration integrated machine, and then transported to the sludge deep treatment workshop.

9. The treatment process according to claim 8, characterized in that: In the step S2, sodium acetate is added as a supplementary carbon source in the anoxic section as needed to help denitrification and reduce the total nitrogen index in the sewage.

10. The treatment process according to claim 8, characterized in that: In step S6, the UV lamp sleeve arranged outside the mercury alloy UV lamp regularly and automatically cleans the dirt film adsorbed on the sleeve wall to ensure that the transmission of UV light intensity is not reduced and the continuous sterilization function is guaranteed.

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