Multi-medium composite deep purification device for town sewage

Abstract

The invention discloses a multi-medium composite deep purification device for town sewage. The multi-medium composite deep purification device comprises a pretreatment process unit, a sewage lifting pump, a biological tank, a sedimentation tank, a denitrification tank, a micro-aeration tank, a filter tank, an ultraviolet disinfection tank, a sludge reflux pump, a residual sludge pump and a sludge dewatering room, a grit chamber of the pretreatment process unit adopts a gas stripping sand discharging device, the gas stripping sand discharging device operates regularly, and a sand-water separator of the gas stripping sand discharging device and a sand discharging device operate synchronously; according to the invention, a gas stripping sludge discharge technology is adopted, so that the problems that time and labor are consumed when a submersible sewage pump, a submersible pump and the like are mounted and maintained underwater, and the submersible sewage pump and the submersible pump are not suitable for some sewage treatment plants with large burial depth are solved; according to the deep purification process consisting of the denitrification tank, the micro-aeration tank and the filter tank, different types of fillers are added to carry out sewage deep treatment, so that the problem that the denitrification and dephosphorization effects are poor under the conditions of low inlet water C / N ratio and insufficient carbon sources is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment devices, and in particular relates to a multi-media composite deep purification device for urban sewage. Background Art

[0002] There is abundant rainwater and groundwater in southern my country's cities, and the mixing of rainwater and sewage is serious, which makes the sewage collected by urban sewage treatment plants generally have the problem of low carbon and high nitrogen and phosphorus. On the other hand, nitrate pollution in urban water bodies is becoming increasingly serious, posing a great threat to the urban water environment, and it is difficult to obtain satisfactory results with biological treatment methods for such low C / N value water bodies.

[0003] At present, the commonly used secondary treatment processes for urban domestic sewage in China mainly include: AAO process, oxidation ditch technology, SBR process series, biofilm method, biological treatment + artificial wetland process, etc. The AAO process has the characteristics of good phosphorus removal and nitrogen removal, but there are many sewage treatment structures, high requirements for operation and management, and high investment; the oxidation ditch process has stable operation, good treatment effect, small sludge production, but low load, large area, and relatively high operating energy consumption; the SBR process series (including CASS process, ICEAS process, UNITANK process and MSBR process, etc.) has a simple process flow, small area, and can achieve the requirements of phosphorus removal and nitrogen removal, but has complex automatic control requirements, large one-time investment, and high system maintenance costs; the biological treatment + artificial wetland process has low operating costs, simple operation and management, and can be coordinated with the surrounding environment, but has low treatment efficiency, large area, and has great limitations in application. In addition, these biological treatment processes are difficult to treat low C / N water bodies.

[0004] Therefore, how to effectively treat low C / N value sewage has become a technical challenge in my country's urban water treatment field, and developing cheap and practical denitrification technology is one of the current research focuses. Summary of the invention

[0005] The invention provides a multi-media composite deep purification device for urban sewage to overcome the problems existing in the prior art.

[0006] To solve the above problems, the technical solution provided by the present invention is as follows:

[0007] The embodiment of the present invention provides a multi-media composite deep purification device for urban sewage, comprising a pretreatment process unit (1), a sewage lifting pump (8), a biological pool (2), a sedimentation tank (3), a denitrification tank (4), a micro-aeration tank (5), a filtration tank (6) and an ultraviolet disinfection tank (7) which are connected in sequence through pipelines; the bottom of the sedimentation tank (3) is connected to a sludge return pump (9) and a residual sludge pump (10) through a pipeline, the sludge return pump (9) is also connected to the biological pool (2) through a pipeline, and the residual sludge pump (10) is connected to a sludge dewatering room (11) through a pipeline; the pretreatment process unit (1) comprises a coarse screen, a regulating tank, a water intake pump room, a fine screen and a grit chamber;

[0008] The sewage to be treated is pretreated through the coarse screen, the fine screen and the grit chamber of the pretreatment process unit (1). The pretreated sewage enters the biological pool (2) through the sewage lifting pump (8) for biological denitrification and phosphorus removal. The effluent of the biological pool (2) flows into the sedimentation tank (3) through the height difference. The effluent after sedimentation in the sedimentation tank (3) enters the deep treatment process system composed of the denitrification tank (4), the micro-aeration tank (5) and the filtration tank (6). The effluent of the deep treatment process system is disinfected in the ultraviolet disinfection tank (7) to achieve the effluent standard. Part of the sludge at the bottom of the sedimentation tank (3) is pumped into the biological pool (2) through the sludge return pump (9) to maintain the concentration of the sludge in the biological pool (2); the other part is pumped into the sludge dewatering room (11) through the residual sludge pump (10). The residual sludge after treatment in the sludge dewatering room (11) forms a mud cake and is transported out.

[0009] In an optional embodiment of the present invention, the sand settling tank of the pretreatment process unit (1) adopts an air lift sand discharge device, the air lift sand discharge device operates regularly, and the sand-water separator of the air lift sand discharge device operates synchronously with the sand discharge device.

[0010] In an optional embodiment of the present invention, the biological pool (2) can adopt any treatment process such as AAO process, oxidation ditch process, SBR series process, biofilm series process, etc.

[0011] In an optional embodiment of the present invention, carbon-based organic matter and limestone are provided in the denitrification pool (4). The carbon-based organic matter has a porous structure, providing a good living environment for microorganisms. At the same time, the carbon-based organic matter has a large C / N ratio, providing a carbon source for denitrifying bacteria.

[0012] In an optional embodiment of the present invention, the micro-aeration tank (5) is filled with unsaturated carbon and calcium system materials, and maintains an aerobic state during normal operation, regularly lifts sludge, and performs backwashing to prevent clogging of the filler.

[0013] In an optional embodiment of the present invention, the filter tank (6) is filled with a multi-media composite filter material, which is kept in an anaerobic state during normal operation, and sludge is regularly airlifted and backflushed to prevent clogging of the filler.

[0014] In an optional embodiment of the present invention, the ultraviolet disinfection pool (7) uses a low-pressure high-intensity ultraviolet lamp with a power of N=15kW to kill bacteria, viruses and other microorganisms in the water in a short time to ensure that the number of fecal coliform bacteria in the final effluent meets the standard.

[0015] In an optional embodiment of the present invention, the sludge dewatering room (11) uses a plate and frame filter press for dewatering, and the moisture content of the sludge after dehydration reaches 70% to 80%.

[0016] Compared with the prior art, the embodiment of the present invention provides a multi-media composite deep purification device for urban sewage, which has the following beneficial effects: (1) The air lift sludge removal technology is adopted to solve the problem of time-consuming and labor-intensive underwater installation and maintenance of submersible sewage pumps and submersible pumps, as well as the problem that submersible sewage pumps and submersible pumps are not suitable for some sewage treatment plants with large burial depths. (2) The multi-media composite deep purification device is adopted to add different types of fillers in the deep purification process section for deep sewage treatment, which solves the problem of poor denitrification and phosphorus removal effects when the carbon source of low C / N influent is insufficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A schematic diagram of a multi-media composite deep purification device for urban sewage provided in an embodiment of the present application.

[0019] Figure 2 This is a graph showing the relationship between the mud discharge efficiency of the air lift mud discharge device and the air intake volume under the condition of a flooding ratio of 0.571 provided in an embodiment of the present application.

[0020] Figure 3 This is a graph showing the relationship between the mud discharge efficiency of the air lift mud discharge device and the air intake volume under the condition of a flooding ratio of 0.633 provided in an embodiment of the present application.

[0021] Figure 4 This is a graph showing the relationship between the mud discharge efficiency of the air lift mud discharge device and the air intake volume under the condition of a flooding rate of 0.75 provided in an embodiment of the present application.

[0022] Figure 5This is a graph showing the relationship between the mud discharge efficiency of the air lift mud discharge device and the air intake volume under the condition of a flooding ratio of 0.833 provided in an embodiment of the present application.

[0023] Figure 6 This is a graph showing the relationship between the mud discharge efficiency of the air lift mud discharge device and the air intake volume under the condition of a flooding ratio of 0.917 provided in an embodiment of the present application.

[0024] Figure 7 A pool bottom mud depth map provided for an embodiment of the present application.

[0025] Figure 8 Schematic diagram of a rotten wood and iron filings biological filter device provided in an embodiment of the present application.

[0026] Fig. 9 This is a COD change diagram of the biofilter effluent provided in the embodiment of the present application.

[0027] Fig.10 This is a graph of TP removal rate of the biofilter provided in an embodiment of the present application.

[0028] Fig.11 This is a graph showing changes in nitrogen in the effluent from biofilter No. 1 provided in an embodiment of the present application.

[0029] Fig.12 This is a graph showing changes in nitrogen in the effluent from biofilter No. 2 provided in an embodiment of the present application.

[0030] Fig.13 This is a graph showing changes in nitrogen in the effluent from biofilter No. 3 provided in the examples of the present application.

[0031] Figure numbers: 1-pretreatment process unit; 2-biological pool; 3-sedimentation tank; 4-denitrification tank; 5-micro-aeration tank; 6-filtration tank; 7-ultraviolet disinfection tank; 8-wastewater lifting pump; 9-sludge return pump; 10-residual sludge pump; 11-sludge dewatering room; a-water inlet; b-sludge return; c-residual sludge lifting; d-residual sludge transportation; e-effluent. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0033] like Figure 1As shown, an embodiment of the present invention provides a multi-media composite deep purification device for urban sewage, including a pretreatment process unit 1, a sewage lifting pump 8, a biological pool 2, a sedimentation tank 3, a denitrification tank 4, a micro-aeration tank 5, a filtration tank 6 and an ultraviolet disinfection tank 7 which are connected in sequence through pipelines; a sludge return pump 9 and a residual sludge pump 10 are connected to the bottom of the sedimentation tank 3 through a pipeline, the sludge return pump 9 is also connected to the biological pool 2 through a pipeline, and the residual sludge pump 10 is connected to a sludge dewatering room 11 through a pipeline; the pretreatment process unit 1 includes a coarse screen, a regulating tank, a water intake pump room, a fine screen and a grit chamber.

[0034] The sewage to be treated is pretreated through the coarse screen, fine screen and grit chamber of the pretreatment process unit 1. The pretreated sewage enters the biological pool 2 through the sewage lifting pump 8 for biological denitrification and phosphorus removal. The effluent from the biological pool 2 flows into the sedimentation tank 3 through the height difference. The effluent after sedimentation in the sedimentation tank 3 enters the deep treatment process system composed of the denitrification tank 4, the micro-aeration tank 5 and the filtration tank 6. The effluent from the deep treatment process system is disinfected in the ultraviolet disinfection tank 7 to achieve the effluent standard. Among them, part of the sludge at the bottom of the sedimentation tank 3 is pumped into the biological pool 2 through the sludge return pump 9 to maintain the concentration of the sludge in the biological pool 2; the other part is pumped into the sludge dewatering room 11 through the residual sludge pump 10. The residual sludge after treatment in the sludge dewatering room 11 forms a mud cake d for external transportation.

[0035] The wastewater to be treated a in this embodiment can be various types of wastewater, such as urban wastewater, black and smelly water, etc. The grit chamber of the pretreatment process unit 1 adopts an air lift sand discharge device, which operates regularly, and the sand-water separator of the air lift sand discharge device operates synchronously with the sand discharge device.

[0036] The biological pool 2 can adopt various treatment processes, such as AAO process, oxidation ditch process, SBR series process, biofilm process series process, etc. The denitrification pool 4 is provided with carbon-based organic matter and limestone. The carbon-based organic matter has a porous structure, which provides a good living environment for microorganisms. At the same time, the C / N ratio of the carbon-based organic matter is very large, which provides a carbon source for denitrifying bacteria such as Pseudomonasstutzeri. Specific design parameters: filter surface hydraulic load (filtration rate) 1.0~2.0m 3 / m 2 h(m / h), denitrification load (filler) 0.05~0.09kgNO3 - -N / m 3 ·d, empty bed hydraulic retention time 60 to 180 min.

[0037] The micro-aeration tank 5 is filled with unsaturated carbon and calcium system materials. It maintains an aerobic state during normal operation, regularly lifts sludge, and performs backwashing to prevent plugging of the filler. Specific design parameters: residence time 0.5-1.5h, BOD5 volume load 0.5kg BOD5 / m3 ·d, design aeration intensity 0.1m 3 / m 2 ·min.

[0038] The filter tank 6 is filled with multi-media composite filter materials. It maintains an anaerobic state during normal operation, regularly lifts sludge, and performs backwashing to prevent plugging of the filler. Specific design parameters: Filter surface hydraulic load (filtration rate) 2.0~4.0m 3 / m 2 h (m / h), empty bed hydraulic retention time 42 ~ 90min. Ultraviolet disinfection pool 7 uses low-pressure high-intensity ultraviolet lamps, power N = 15kW, to kill bacteria, viruses and other microorganisms in the water in a short time to ensure that the number of fecal coliform bacteria in the final effluent meets the standard ≤ 10 3 The sludge dewatering room 11 uses a plate and frame filter press for dewatering, and the sludge moisture content reaches 70% to 80% after dehydration.

[0039] The following further describes the multi-media composite deep purification device for urban sewage of the present application with specific examples. This section further describes the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means adopted in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. Specific embodiment 1

[0041] The embodiment of the present application provides a method for perforated air lift to remove mud. The air lift sand removal device adopts an air compressor with a model of OTS-550×2-50L, a rated exhaust pressure of 7.0bar, a nominal volume flow of 80L / min, and an overall size of 73×36×63cm. The air inlet pipe has a hose with an inner diameter of 6mm. The inner diameter of the air inlet is 10mm, and the bottom end is connected to the air inlet pipe. There is a cover plate at the upper end, and the compressed air enters the lifting riser through the holes on the cover plate. The lifting riser and the perforated pipe both use plastic pipes with an inner diameter of 40mm. The connection method adopts hot melt connection, and the holes are drilled with an electric drill. The measuring device is an air lift flowmeter with models LZT-08A10M-V5-50L / min and LZT-08A10M-V 10-100L / min, which is used to measure the exhaust volume of the air compressor.

[0042] Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 The following is a graph showing the relationship between the sludge removal efficiency of conventional gas lift and perforated gas lift with holes of 18mm, 20mm and 22mm as a function of air intake under the conditions of flooding rates of 0.571, 0.633, 0.75, 0.833 and 0.917, respectively. Figure 7 This is a diagram of the mud accumulation height for conventional gas lift mud removal and perforated gas lift mud removal with holes of 18mm, 20mm and 22mm respectively.

[0043] When the flooding ratio is 0.571, the conventional air lift and the perforated air lift with a hole diameter of 20 mm and 22 mm reach the maximum mud discharge efficiency of the device at an air intake of 60 L / min, which are 18.41%, 15.98% and 19.86% respectively. The perforated air lift with a hole diameter of 18 mm reaches the maximum mud discharge efficiency of 12.27% at an air intake of 65 L / min. The results are shown in Figure 2 shown.

[0044] When the flooding ratio is 0.633, the conventional air lift reaches the maximum mud discharge efficiency of 27.45% at an air intake of 55L / min, the perforated air lift with a hole diameter of 18mm reaches the maximum mud discharge efficiency of 17.27% at an air intake of 65L / min, and the perforated air lift with hole diameters of 20mm and 22mm both reach the maximum mud discharge efficiency at an air intake of 60L / min, which are 22.09% and 27.40%, respectively. Figure 3 shown.

[0045] When the flooding rate is 0.75, the conventional air lift reaches the maximum mud removal efficiency of 34.48% at an air intake of 55L / min, and the perforated air lift reaches the maximum mud removal efficiency at an air intake of 60L / min, which are 22.80%, 29.28% and 35.76% respectively. Figure 4 shown.

[0046] When the flooding rate is 0.833, the conventional air lift reaches the maximum mud removal efficiency of 40.67% at an air intake of 50L / min, and the perforated air lift reaches the maximum mud removal efficiency at an air intake of 55L / min, which are 27.05%, 34.60% and 43.24% respectively. Figure 5 shown.

[0047] When the flooding rate is 0.917, both conventional gas lift and perforated gas lift reach the maximum mud removal efficiency at an air intake of 50 L / min, which are 48.39%, 31.87%, 40.60% and 50.33% respectively. Figure 6 shown.

[0048] The sludge accumulation height of conventional air lift sludge discharge is much greater than that of perforated air lift sludge discharge device when x<30cm. The sludge accumulation depth of perforated air lift decreases with the distance from the riser. The sludge accumulation depth of perforated air lift sludge discharge with hole diameters of 18mm, 20mm, and 22mm is all at x=0cm, that is, the highest at the farthest distance from the riser. The maximum sludge accumulation depths are 13.5cm, 17.2cm, and 21.7cm, respectively. According to the ratio of the total sludge height at the first and last ends minus the sludge height, the uniformity of perforated air lift sludge discharge with diameters of 18mm, 20mm, and 22mm is calculated to be 0.845, 0.778, and 0.696, respectively. The results are as follows Figure 7 shown.

[0049] According to the above specific effects, the comparative test of mud discharge effect between perforated air lift and conventional air lift shows that the mud discharge effect of perforated air lift with a hole diameter of 22 mm is better; the mud discharge efficiency of perforated air lift is not greatly improved compared with conventional air lift, but the mud discharge uniformity is significantly better than that of conventional air lift. Specific embodiment 2

[0051] The embodiment of the present application provides a biofilter filler of rotten wood and iron filings. The rotten wood filler is made by sawing and breaking rotten wood branches into smaller wood blocks with a particle size between 0.2 and 0.5 cm and a length between 0.4 and 0.6 cm. After washing the rotten wood dust with tap water, it is naturally air-dried for use. The iron filings are screened and have a particle size between 0.2 and 0.5 cm. Before use, the iron filings are soaked in a 10% NaOH solution until the impurities attached to the surface are completely floated, and then the iron filings are soaked in a 5% HCl solution for 10 to 30 minutes to further remove the rust on the surface, and finally the surface of the iron filings is rinsed with clean water and the surface moisture is absorbed with absorbent paper.

[0052] The simulated wastewater is prepared by mixing sodium acetate (CH3COONa), potassium nitrate (KNO3), potassium dihydrogen phosphate (KH2PO4) and tap water in a certain proportion. The pH of the prepared water is adjusted by NaOH, HCl and NaHCO3. The specific water quality indicators of the artificially prepared wastewater are shown in Table 1, and the measured water quality is shown in Table 2:

[0053] Table 1 Composition of artificial wastewater

[0054] Component name Concentration (mg / l) Component name Concentration (mg / l) <![CDATA[KNO3]]> 81.5 <![CDATA[MgSO4·7H2O]]> 30 <![CDATA[KH2PO4]]> 21.94 <![CDATA[CaCl2]]> 10 Trace element liquid 1ml / L

[0055] Table 2 Water quality of artificial wastewater

[0056] COD(mg / l) 20-40 <![CDATA[NO3 - -N(mg / l)]]> 40-50 TP(mg / l) 4-10 pH 6-8

[0057] Experimental biofilter test equipment such as Figure 8As shown, the reactor body is a cylinder made of organic glass, which is fixed on the supporting iron frame by flange so as to be placed stably on the ground. Geometric dimensions (inner diameter × height): 10cm × 170cm. The biofilter adopts an upward flow method. From bottom to top, the reactor consists of an inlet buffer zone (20cm), a perforated filter plate, a supporting layer (10cm), a packing layer (100cm), a zeolite layer (15cm) and an outlet buffer zone, with a total effective volume of about 15L. The packing layer is filled with rotten wood and iron filings with a height of H = 100cm, and sampling ports are set at 100cm, 80cm, 60cm, 40cm and 20cm respectively.

[0058] The biofilter was filled with rotten wood and iron filings, and three different filling methods were used for experiments. All the fillings were compacted. In biofilter No. 1, iron filings were in the lower layer and rotten wood in the upper layer, each filled with 50 cm; in biofilter No. 2, rotten wood was in the lower layer and iron filings were in the upper layer, each filled with 50 cm; biofilter No. 3 was filled in 3 layers, and the biofilter was filled with 25 cm iron filings, 50 cm rotten wood, and 25 cm iron filings from bottom to top. The wastewater was pumped into the biofilter from bottom to top using a peristaltic pump, and the startup and stable operation of the biofilter were observed. The removal effect and operation of the reactor under different filling methods, influent pH value, nitrate nitrogen concentration, and hydraulic retention time were compared, providing a theoretical reference for the operation of the denitrification process in actual sewage treatment plants.

[0059] The COD of the effluents from the three biofilters was relatively high from 0 to 7 days, and then gradually stabilized. The COD of the effluents from the biofilters was higher than that of the influents during the whole process, which verified that the decayed wood did have the function of slow-release carbon source. The COD of the effluent from biofilter No. 1 was significantly higher than that from biofilters No. 2 and No. 3, and the COD of the effluents from biofilters No. 2 and No. 3 were relatively close. After 11 days, the COD values ​​of the effluents were all stabilized below 70 mg / L. The results are as follows: Fig. 9 shown.

[0060] The influent TP fluctuated between 4.23mg / L and 8.35mg / L, and the average influent TP concentration was 5.69mg / L. Biofilters 1, 2, and 3 all had good TP removal effects, with average TP removal rates of 80.44%, 82.66%, and 79.21%, respectively. During the operation, the TP removal rates of the biofilters remained between 75% and 86%, and there was no significant difference between the biofilters. The results are shown in Fig.10 shown.

[0061] From the first day of operation, each biofilter has - -N removal has a certain effect, because iron filings can quickly chemically reduce NO3 - -N. No. 1 Biofilter NO3 --N concentration decreased rapidly, falling to less than 4 mg / L within 6 days, and then the decline slowed down, and NO3 - -N is basically stable at around 1mg / L, and has a negative impact on NO3 - -N removal effect is very good. However, the effluent NH4 + -N was significantly higher than the other two cases, and the effluent ammonia nitrogen concentration was almost twice that of the No. 2 biofilter. By the end of the operation, NH4 + -N concentrations are higher than 30mg / L. The influent of No. 2 biofilter first passes through the rotten wood layer, where the denitrifying bacteria in the rotten wood layer remove nitrate nitrogen, and then passes through the iron filings layer, where the iron filings can reduce and remove the remaining nitrate nitrogen that has not been removed by the denitrifying bacteria, so the effluent NH4 + -N concentration was greatly reduced, and basically maintained at around 15 mg / L in the second week of operation of the biofilter. - -N removal effect is slightly worse than the other two biofilters. Biofilter No. 3 has the best effect. The influent first passes through the iron filings layer. After iron filings pretreatment, part of the nitrate nitrogen can be removed, and the biodegradability of the influent can be improved through micro-electrolysis. Then the influent passes through the rotten wood layer. The iron ions carried in the water can participate in cellular electron transfer, enhance microbial respiration, and help increase the amount of microorganisms, which promotes the degradation and removal of nitrate nitrogen in this layer of water by denitrifying bacteria. In addition, the ammonia nitrogen generated in the upper layer can react with nitrate nitrogen and be removed, which helps to reduce the ammonia nitrogen concentration in the effluent. After that, the influent passes through the iron filings layer again, and the remaining nitrate nitrogen can be further removed by zero-valent iron and micro-electrolysis. At the same time, part of the pollutants can also be removed through the adsorption and flocculation of the iron filings layer. The results are as follows Fig.11 , Fig.12 , Fig.13 shown.

[0062] According to the above specific implementation effect description, the best effect is achieved by filling the filler with iron filings at the top and bottom and rotten wood in the middle layer. Through this filling method, a better denitrification and denitrification effect is achieved in the case of low-carbon source sewage. Specific embodiment 3

[0064] Treatment object: urban sewage

[0065] Influent concentration: COD = 250mg / L, BOD5 = 120mg / L, NH3-N = 25mg / L, SS = 180mg / L, TP = 3.0mg / L, TN = 35mg / L

[0066] Processing requirements: Level A

[0067] Process flow: coarse screen-fine screen-advection grit chamber A 2O- Sedimentation tank - Denitrification tank - Micro-aeration tank - Filtration tank - Disinfection tank, where the denitrification tank uses carbon organic matter and limestone fillers, the micro-aeration tank uses unsaturated carbon and calcium system fillers, and the filtration tank uses modified rotten wood fillers and composite active iron-aluminum dephosphorization fillers.

[0068] Treatment effect: COD = 50mg / L, BOD5 = 10mg / L, NH3-N = 5mg / L, SS = 10mg / L, TP = 0.5mg / L, TN = 15mg / L, COD, BOD5, ammonia nitrogen, SS, total phosphorus and total nitrogen removal rates are 80%, 92%, 80%, 94%, 83% and 57% respectively Specific embodiment 4

[0070] Treatment object: industrial wastewater

[0071] Influent concentration: COD = 330mg / L, BOD5 = 155mg / L, NH3-N = 25mg / L, SS = 200mg / L, TP = 3.0mg / L, TN = 35mg / L

[0072] Processing requirements: Level A

[0073] Process flow: sedimentation tank - anaerobic tank - denitrification tank - micro-aeration tank - filtration tank - disinfection tank, in which the denitrification tank uses carbon-based organic matter and limestone fillers, the micro-aeration tank uses unsaturated carbon and calcium system fillers, and the filtration tank uses modified rotten wood fillers and composite active iron-aluminum dephosphorization fillers

[0074] Treatment effect: COD = 50mg / L, BOD5 = 10mg / L, NH3-N = 5mg / L, SS = 10mg / L, TP = 0.5mg / L, TN = 15mg / L, COD, BOD5, ammonia nitrogen, SS, total phosphorus and total nitrogen removal rates are 84.8%, 93.5%, 80%, 95%, 83%, 57% respectively Specific embodiment 5

[0076] Treatment object: Class V lake water

[0077] Influent concentration: COD = 37 mg / L, BOD5 = 12.3 mg / L, NH3-N = 0.56 mg / L, TP = 0.75 mg / L, TN = 1.69 mg / L

[0078] Treatment requirements: surface water class III

[0079] Process flow: sedimentation tank - anaerobic tank - denitrification tank - micro-aeration tank - filtration tank - disinfection tank, in which the denitrification tank uses carbon-based organic matter and limestone fillers, the micro-aeration tank uses unsaturated carbon and calcium system fillers, and the filtration tank uses modified rotten wood fillers and composite active iron-aluminum dephosphorization fillers

[0080] Treatment effect: COD=20mg / L, BOD5=4mg / L, NH3-N=0.2mg / L, TP=0.2mg / L, TN=1mg / L, COD, BOD5, ammonia nitrogen, SS, total phosphorus and total nitrogen removal rates were 45.9%, 67.5%, 64.3%, 73.3% and 40.8% respectively.

[0081] In summary, although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A multi-media composite deep purification device for urban sewage, characterized in that: The invention comprises a pretreatment process unit (1), a sewage lifting pump (8), a biological pool (2), a sedimentation tank (3), a denitrification tank (4), a micro-aeration tank (5), a filtration tank (6) and an ultraviolet disinfection tank (7) which are connected in sequence through pipelines; the bottom of the sedimentation tank (3) is connected to a sludge return pump (9) and a residual sludge pump (10) through a pipeline, the sludge return pump (9) is also connected to the biological pool (2) through a pipeline, and the residual sludge pump (10) is connected to a sludge dewatering room (11) through a pipeline; the pretreatment process unit (1) comprises a coarse screen, a regulating tank, a water intake pump room, a fine screen and a grit chamber; The sewage to be treated is pretreated through the coarse grid, fine grid and grit chamber of the pretreatment process unit (1). The pretreated sewage enters the biological pool (2) through the sewage lifting pump (8) for biological denitrification and phosphorus removal. The effluent of the biological pool (2) flows into the sedimentation tank (3) through the height difference. The effluent after sedimentation in the sedimentation tank (3) enters the deep purification process system composed of the denitrification tank (4), the micro-aeration tank (5) and the filtration tank (6). The effluent of the deep purification process system is disinfected in the ultraviolet disinfection tank (7) to achieve the effluent standard. Part of the sludge at the bottom of the sedimentation tank (3) is pumped into the biological pool (2) through the sludge return pump (9) to maintain the concentration of the sludge in the biological pool (2); the other part is pumped into the sludge dewatering room (11) through the residual sludge pump (10). The residual sludge after treatment in the sludge dewatering room (11) forms a mud cake and is transported out.

2. A multi-media composite deep purification device for urban sewage according to claim 1, characterized in that: The grit chamber of the pretreatment process unit (1) adopts an air lift sand discharge device, which operates regularly, and the sand-water separator of the air lift sand discharge device operates synchronously with the sand discharge device.

3. A multi-media composite deep purification device for urban sewage according to claim 1, characterized in that: The biological pond (2) can adopt any treatment process such as AAO process, oxidation ditch process, SBR series process, and biofilm process series process.

4. A multi-media composite deep purification device for urban sewage according to claim 1, characterized in that: The denitrification pool (4) is provided with carbon-based organic matter and limestone. The carbon-based organic matter has a porous structure, providing a good living environment for microorganisms. At the same time, the carbon-based organic matter has a large C / N ratio, providing a carbon source for Pseudomonas stutzeri-type denitrifying bacteria.

5. The multi-media composite deep purification device for urban sewage according to claim 1, characterized in that: The micro aeration tank (5) is filled with unsaturated carbon and calcium system materials, and maintains an aerobic state during normal operation. Sludge is regularly airlifted and backflushed to prevent clogging of the filler.

6. A multi-media composite deep purification device for urban sewage according to claim 1, characterized in that: The filter tank (6) is filled with a multi-media composite filter material, which is kept in an anaerobic state during normal operation, and the sludge is regularly airlifted and backflushed to prevent clogging of the filler.

7. The multi-media composite deep purification device for urban sewage according to claim 1 is characterized in that: The ultraviolet disinfection pool (7) uses a low-pressure high-intensity ultraviolet lamp with a power of N=15kW to kill bacteria, viruses and other microorganisms in the water in a short time to ensure that the number of fecal coliform bacteria in the final effluent meets the standard of ≤10 3 Pieces / L.

8. The multi-media composite deep purification device for urban sewage according to claim 1, characterized in that: The sludge dewatering room (11) uses a plate-frame filter press for dewatering, and the moisture content of the sludge reaches 70% to 80% after dehydration.

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