CN202808537U - Town sewage deep treatment system - Google Patents

Abstract

The utility model discloses a town sewage deep treatment system and aims at solving the problems that the treated sewage can not meet the national standard in the prior art, a flow is long, occupying area is large and operating cost is high. The town sewage deep treatment system comprises a grid sewage treatment device, a grit chamber, an oxygen deficiency tank, an MBR (membrane biological reactor) aerobic tank, an adsorption filter tank and a disinfection tank which are sequentially communicated, wherein a nano ferric oxide hydrate compound adsorbent is filled inside the adsorption filter tank, and a sludge outlet used for discharging sludge is arranged at the bottom of the MBR aerobic tank. The town sewage deep treatment system disclosed by the utility model has the advantages of short flow, low cost, low operating cost, high stability and good sewage treatment effect.

Description

Urban sewage advanced treatment system

technical field

The utility model relates to a treatment system for urban sewage, in particular to an advanced treatment system for urban sewage.

Background technique

With the continuous growth of my country's population and rapid economic development, water consumption and drainage are increasing year by year, while limited water resources are constantly being polluted, and the water environment is constantly deteriorating. At the same time, a large number of sewage treatment plants in our country were built during the "Ninth Five-Year Plan" and "Tenth Five-Year Plan", and the discharge standards are relatively low, which can no longer meet the requirements of total volume control. State Environmental Protection Administration Huanfa [2005] No. 110 "Notice on Strictly Implementing Pollutant Discharge Standards for Urban Sewage Treatment Plants" stated for the first time that "in order to prevent eutrophication of waters, the effluent of urban domestic sewage treatment plants When entering the key river basins determined by the country and the province, lakes, reservoirs and other closed and semi-closed waters, the standard A of the first-level standard in the "Standard" should be implemented. Announcement No. 21 in 2006 reiterated this issue again, which actually directly expanded the scope of application of the first-level standard A in GB18918-2002 to the vast majority of urban sewage treatment plants at the regulatory level. The renovation of standard A sewage treatment systems will be implemented in large numbers in many river basins and provinces. In addition, although my country's total water resources are relatively large, ranking sixth in the world, due to its large population, the per capita water resources are only a quarter of the world's. At the same time, my country's water resources are still unevenly distributed, with more in the south and less in the north. Phenomenon, so my country is a country with very scarce water resources. The recycling and reuse of sewage can save a lot of fresh water and supplement the shortage of water resources, and urban sewage has the advantages of local availability, stability and reliability, and high guarantee rate, which is of great significance to alleviate the shortage of water resources in our country. Therefore, it is imminent to develop a process suitable for advanced treatment and regeneration of urban sewage.

At present, secondary biological treatment processes are widely used in China's urban sewage treatment, including: traditional activated sludge process, delayed aeration activated sludge process, SBR (Sequencing Batch Reactor Activated Sludge Process) sequencing batch activated sludge process, AB, UNITANK And oxidation ditch process, A/O and A ² /O, etc. After the sewage is treated, the effluent can generally meet the GB18918-2002 Class B standard. In order to further improve the treatment effect and make the effluent meet the first-class A standard and the reuse standard, advanced treatment is often carried out in the subsequent three-stage treatment process coupled with coagulation sedimentation, filtration, and activated carbon adsorption. However, this urban sewage advanced treatment process has the disadvantages of long process, high investment, high operating cost and poor stability.

MBR, also known as membrane bioreactor, is a new type of water treatment technology that combines membrane treatment unit and biological treatment unit. It integrates biodegradation, sedimentation and filtration, reduces the demand for equipment, and is currently being gradually accepted. Pay attention to. MBR has the characteristics of stable effluent quality, high treatment capacity, short process flow, small footprint, and convenient operation and management. Its removal effect on COD, NH ₃ -N and SS suspended matter is significantly better than traditional secondary biological processes. However, MBR generally has a very long sludge age, which makes phosphate enriched in the system for a long time, resulting in poor phosphorus removal effect of the system. Judging from the operation results of most MBRs, the concentration of phosphorus in the effluent is not ideal, and it is difficult to reduce it to below 1mg/L, which seriously restricts the application of this process in the field of advanced sewage treatment and reuse.

Adsorption is considered to be one of the most effective methods for treating phosphorus pollution in water bodies. Research results in the past two decades have shown that hydrated iron oxide has a high specific surface area and surface hydroxyl density, has a high degree of selective adsorption of phosphorus, and can be regenerated and reused by adjusting the pH. The particle size of the iron oxide is extremely fine. If it is directly used in the adsorption filter, it will cause a high pressure loss and make the adsorption system unable to operate stably. At present, in order to solve this engineering problem, hydrated iron oxide is often immobilized in porous large particle carriers to prepare composite adsorbents.

Based on the above, we can see that the current treatment of urban sewage has the following problems:

1: There is an urgent contradiction between the urgent need to meet the national first-class A standard for urban sewage treatment and the poor effect of existing urban sewage treatment;

2: The existing urban sewage treatment systems and methods have long processing and reuse processes, high investment, high operating costs and poor stability.

Utility model content

In order to overcome the above problems, the utility model provides an urban sewage treatment system with short flow, low cost, low operating cost and high stability.

In order to achieve the above purpose, the urban sewage advanced treatment system of the present utility model includes a grid sewage treatment device for removing suspended solids, a grit chamber for depositing inorganic particles, an anoxic pool for denitrification and denitrification treatment, and an MBR that are connected in sequence. Aerobic pools, adsorption filters and disinfection pools;

in,

The bottom of the MBR aerobic tank is provided with a sludge outlet;

The adsorption filter tank is filled with a composite adsorbent of nanometer hydrated iron oxide for further dephosphorization of sewage.

Further, the grid sewage treatment device includes a coarse grid sewage treatment machine and a fine grid sewage treatment machine; the grid gap of the coarse grid sewage treatment machine is 20-30mm; the fine grid sewage treatment machine grid The strip gap is 5-10mm.

Further, the grit chamber is an advection type grit chamber, a swirl type grit chamber or an aeration type grit chamber.

Further, the MBR aerobic pool includes a flat MBR membrane module.

Further, the sludge outlet of the MBR aerobic tank is also communicated with the anoxic tank through a pipeline; the pipeline is used to return part of the sludge to the anoxic tank, and the return ratio is 30%- 60%.

Further, the loaded nanometer hydrated iron oxide includes a carrier, and the carrier is a macroporous anion exchange resin, activated carbon, diatomaceous earth or pulverized coal.

Further, the adsorption filter tank also includes an input pipe for inputting a sodium hydroxide aqueous solution with a specific gravity of 2%-5%.

Further, the disinfection pool is an ultraviolet disinfection pool.

Further, sludge dewatering equipment is connected to the rear end of the sludge outlet.

The beneficial effects of the utility model urban sewage advanced treatment system:

1. The urban sewage advanced treatment system of this utility model adopts the combination of MBR membrane technology and the adsorption of nanometer hydrated iron oxide composite adsorbent, and uses the hydrated iron oxide composite adsorbent to carry out the advanced treatment of dephosphorization, thereby making up for the dephosphorization effect of MBR Bad enough.

2. The urban sewage advanced treatment system of this utility model, after the nano-hydration iron oxide composite adsorbent is saturated, is regenerated by sodium hydroxide aqueous solution, and has good regeneration performance, high mechanical strength, and can be reused.

3. The urban sewage advanced treatment system of this utility model has good effect after sewage treatment. After treatment, COD<50mg/L, BOD<10mg/L, SS<10mg/L, TP<0.2mg/L, NH ₃ -N<3mg/L, the water quality of the effluent is better than the A standard in the first grade standard of GB18918-2002.

4. The urban sewage advanced treatment system of the utility model has the characteristics of short process, low investment, small floor area and stable operation effect.

Description of drawings

Fig. 1 is a schematic structural view of the urban sewage treatment system described in the first embodiment of the utility model.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described further.

Embodiment one:

As shown in Figure 1, the urban sewage advanced treatment system in this example includes grid sewage treatment devices connected in sequence, advection grit chambers, anoxic tanks, and MBR aerobic tanks, which are filled with macroporous anion exchange resins as carriers. The adsorption filter and disinfection pool of the nano-hydration iron oxide composite adsorbent, the sewage treatment scale is 50,000 m3/d, and the influent is urban domestic sewage.

The grid sewage treatment device includes a coarse grid sewage treatment machine and a fine grid sewage treatment machine; the grid gap of the coarse grid sewage treatment machine is 30mm; the grid gap of the fine grid sewage treatment machine is 8mm; grid sewage treatment device is used to remove suspended solids in sewage;

The advection grit chamber is used for settling inorganic particles in sewage;

The anoxic pool is used for denitrification and denitrification treatment of sewage;

The MBR aerobic pool is used for deep purification treatment of sewage, and a sludge outlet is provided at the bottom;

In particular, sludge dehydration equipment is connected to the rear end of the sludge outlet;

The adsorption filter is used to further dephosphorize the sewage;

The disinfection tank is used for disinfection and sterilization of sewage.

Further, the sludge outlet of the MBR aerobic tank is also communicated with the anoxic tank through a pipeline, and the pipeline is used to return part of the sludge to the anoxic tank, usually with a return ratio of 30%- 60%.

The urban sewage advanced treatment system described in this example includes the following steps when performing sewage treatment:

1) The sewage to be treated passes through the coarse grid sewage treatment machine with a grid gap of 30mm and the fine grid sewage treatment machine with a grid gap of 8mm to intercept larger suspended solids in the water;

2) Then the water enters the advection grit chamber to remove inorganic particles in the water, and the hydraulic retention time is 60s;

3) The effluent of the flat-flow grit chamber enters the anoxic tank, and the denitrification and denitrification treatment is carried out under the condition of stirring. Concentration 1.0mg/L;

4) The effluent from the anaerobic pool enters the aerobic pool with a built-in MBR flat membrane. The hydraulic retention time in the pool is 4 hours, the MLSS is 10-12g/L, and the dissolved oxygen maintained at 3.0mg/L is maintained through blast aeration;

In step 4), at least part of the generated sludge is dehydrated by a plate-and-frame filter press and transported outside, and the treated sludge is rich in nutrients and can be landfilled or used as agricultural fertilizer;

5) The effluent from the MBR aerobic tank enters the adsorption filter tank, which is filled with nano-hydration iron oxide composite adsorbent with macroporous anion exchange resin as the carrier, and the adsorption flow rate is 40 bed volume per hour. It is 2% NaOH solution, at a temperature of 20 degrees Celsius, the regeneration is carried out at a bed volume per hour.

6) The effluent of the adsorption filter is sterilized and disinfected.

In addition, the MBR aerobic tank also returns part of the sludge to the anoxic tank through the pipeline at a ratio of 30%-60%. However, the reflux ratio in this embodiment is 50%.

After the operation of the urban sewage advanced treatment system in this embodiment, a good operation effect has been obtained, the effluent turbidity <5NTU, COD <50mg/L, BOD <10mg/L, SS suspended solids <10mg/L, TP phosphorus content <0.2 mg/L, NH3-N ammonia nitrogen content <5mg/L, meeting the Grade A standard in the "Urban Miscellaneous Water Quality Standard" GB/T 18920-2002 and "Urban Sewage Treatment Plant Pollutant Discharge Standard" GB18918-2002. In addition, the urban sewage advanced treatment system described in this embodiment also has the advantages of short treatment process, low investment, low operating cost, small footprint, and stable operation.

Embodiment two:

The urban sewage advanced treatment system in this example includes a grid sewage treatment device, a swirl type grit chamber, an anoxic tank, an MBR aerobic tank, an adsorption filter and a disinfection tank connected in sequence; the grid sewage treatment device It includes two stages, the first stage is a coarse grid sewage treatment machine with a grid gap of 25mm, and the second level is a fine grid sewage treatment machine with a grid gap of 5mm. In a specific application process, the grid sewage treatment device can be one-stage or multi-stage. When the grid sewage treatment device has only one stage, the interval between the grid bars is preferably 6-12 mm, which can also meet the first-level A standard of advanced sewage treatment. But there is a problem, and the interception of the first-level gate sewage treatment machine needs frequent cleaning, otherwise it will cause problems such as difficulty in water discharge. When the grid sewage treatment device adopts 3 or 4 or more stages, the hardware investment cost of the system is increased, and the complexity of the structure is increased. Therefore, the two-stage structure of the coarse grid sewage treatment machine and the fine grid sewage treatment machine is the preferred structure. The MBR aerobic pool is provided with a flat MBR membrane module. The disinfection pool is an ultraviolet disinfection pool with a built-in ultraviolet disinfection device.

The sewage treatment scale of the urban sewage advanced treatment system described in this embodiment is 20,000 m3/d, and the influent is urban domestic sewage.

The urban sewage advanced treatment system described in this example includes the following steps in the specific urban sewage advanced treatment:

1) The sewage to be treated passes through the coarse grid sewage treatment machine with a grid gap of 25mm and the fine grid sewage treatment machine with a grid gap of 5mm to intercept larger suspended solids in the water;

2) Then the water enters the cyclone grit chamber to remove inorganic particles in the water, and the hydraulic retention time is 40s;

3) The effluent of the swirling grit chamber and the reflux liquid of the aerobic tank enter the anoxic tank together, and carry out denitrification and denitrification treatment under the condition of stirring. The hydraulic retention time in the tank is 2h, and the MLSS is 2-3g/L. Dissolved oxygen concentration 1.5mg/L;

4) The effluent from the anaerobic pool enters the aerobic pool with a built-in MBR flat membrane. The hydraulic retention time in the pool is 6 hours, the MLSS is 8-10g/L, and the dissolved oxygen is maintained at 3.0mg/L through blast aeration;

In step 4), it also includes returning part of the generated sludge to the anaerobic tank through the sludge pipe at the bottom of the aerobic tank. The reflux ratio is 40%. buried or used as fertilizer;

5) The effluent of the MBR aerobic tank enters the adsorption filter tank, which is filled with nano-hydration iron oxide composite adsorbent with activated carbon as the carrier, the adsorption flow rate is 50 bed volume per hour, and the material after adsorption saturation is used with a specific gravity of 2%. NaOH solution, at a temperature of 25 degrees Celsius, regenerates at 2 bed volumes per hour;

6) The effluent from the adsorption filter enters the ultraviolet disinfection pool for sterilization.

After the operation of the urban sewage advanced treatment system described in this embodiment, good operation results have been obtained, effluent turbidity <3NTU, COD<50mg/L, BOD<10mg/L, SS<10mg/L, TP<0.1mg /L, NH3-N<3mg/L, meeting the Class A standard in the "Urban Miscellaneous Water Quality Standard" GB/T 18920-2002 and "Pollutant Discharge Standard for Urban Sewage Treatment Plant" GB18918-2002.

Embodiment three:

The urban sewage advanced treatment system in this example has a scale of 10,000 m3/d, mainly including grid sewage treatment devices, aerated grit chambers, anoxic ponds, MBR aerobic ponds, adsorption filters and disinfection ponds. The grid sewage treatment device includes a coarse grid sewage treatment machine and a fine grid sewage treatment machine.

The sewage treatment of the urban sewage advanced treatment system in this example includes the following steps:

1) The sewage to be treated passes through the coarse grid sewage treatment machine with a grid gap of 20mm and the fine grid sewage treatment machine with a grid gap of 3mm to intercept larger suspended solids in the water;

2) Then the water enters the aerated grit chamber to remove inorganic particles in the water, and the hydraulic retention time is 30s;

3) The effluent of the aerated grit chamber and the reflux liquid of the aerobic tank enter the anoxic tank together, and carry out denitrification and denitrification treatment under the condition of stirring. The hydraulic retention time in the tank is 1h, and the MLSS is 3-4g/L. Dissolved oxygen concentration 1.0mg/L;

4) The effluent from the anaerobic pool enters the aerobic pool with built-in MBR flat membrane, the hydraulic retention time in the pool is 4 hours, the MLSS is 8-10g/L, and the dissolved oxygen is maintained at 3.0mg/L through blast aeration;

In step 4), it also includes returning part of the generated sludge to the anaerobic tank through the pipeline at the bottom of the MBR aerobic tank. The return ratio is 60%. Used in landfill or as agricultural fertilizer;

5) The effluent of the MBR aerobic tank enters the adsorption filter tank, which is filled with nano-hydration iron oxide composite adsorbent with diatomite as the carrier, the adsorption flow rate is 50 bed volume per hour, and the material after adsorption saturation is used with a specific gravity of 2.5 % NaOH solution at a temperature of 20 degrees Celsius for regeneration at 2 bed volumes per hour.

6) The effluent from the adsorption filter enters the ultraviolet disinfection pool with built-in ultraviolet equipment, and is sterilized.

The sewage treated by the urban sewage advanced treatment system described in this embodiment has a good cleaning effect and meets the requirements in the "Urban Miscellaneous Water Quality Standard" GB/T 18920-2002 and "Urban Wastewater Treatment Plant Pollutant Discharge Standard" GB18918-2002 Grade A standard. The specific cleaning parameters are as follows:

Effluent turbidity<5NTU, COD<50mg/L, BOD<10mg/L, SS<10mg/L, TP<0.2mg/L, NH3-N<5mg/L.

Embodiment four:

The sewage treatment scale of the urban sewage advanced treatment system in this example is 6000m3/d, and the influent is urban domestic sewage. The urban sewage advanced treatment system includes a grid sewage treatment device, a swirl type sink, and a coarse grid sewage treatment machine with a grid interval of 25 mm and a fine grid sewage treatment machine with a grid interval of 3 mm, which are connected in sequence. Sand pool, anoxic pool, MBR aerobic pool, adsorption filter filled with nano-hydration iron composite adsorbent with coal as carrier, and disinfection pool;

The grid sewage treatment device is used to remove suspended solids in sewage;

The cyclone grit chamber is used to settle inorganic particles in sewage;

The anoxic pool is used for nitrification and denitrification treatment of sewage;

The MBR aerobic pool is used for deep purification treatment of sewage, and the bottom is provided with a sludge outlet; the rear end of the sludge outlet is connected with sludge dehydration equipment;

The adsorption filter tank is provided with an input pipe for inputting NaOH aqueous solution to further dephosphorize the sewage;

The disinfection tank is used for disinfection and sterilization of sewage.

In this example, the urban sewage advanced treatment system includes the following steps for sewage treatment:

1) The sewage to be treated passes through the coarse grid with a grid gap of 25mm and the fine grid with a grid gap of 3mm to intercept larger suspended matter in the water;

2) Then the water enters the cyclone grit chamber to remove inorganic particles in the water, and the hydraulic retention time is 60s;

3) The effluent of the swirling grit chamber and the reflux liquid of the aerobic tank enter the anoxic tank together, and carry out denitrification and denitrification treatment under the condition of stirring. The hydraulic retention time in the tank is 1h, and the MLSS is 2-3g/L. Dissolved oxygen concentration 1.5mg/L;

4) The effluent from the anaerobic tank enters the aerobic tank with a built-in flat MBR membrane module. The hydraulic retention time in the tank is 2 hours, the MLSS is 10-12g/L, and the dissolved oxygen maintained at 3.0mg/L is maintained through blast aeration;

In step 4), it also includes returning part of the generated sludge to the anaerobic tank through the sludge pipe at the bottom of the aerobic tank. Landfill or use as agricultural fertilizer;

5) The effluent of the MBR aerobic tank enters the adsorption filter tank, and the adsorption flow rate is 50 bed volumes per hour. The nano-hydration iron oxide composite adsorbent absorbs the saturated material, and the NaOH solution with a specific gravity of 2.5% is used. At a temperature of 25 degrees Celsius, Regeneration was performed at 2 bed volumes per hour.

6) The effluent from the adsorption filter enters the ultraviolet disinfection pool with built-in ultraviolet equipment, and is sterilized.

After the operation of this project, good operation results have been obtained, effluent turbidity <5NTU, COD<40mg/L, BOD<10mg/L, SS<5mg/L, TP<0.1mg/L, NH3-N<3mg/L L, meeting the Grade A standard in the "Urban Miscellaneous Water Quality Standard" GB/T 18920-2002 and "Pollutant Discharge Standard for Urban Sewage Treatment Plant" GB18918-2002.

Comprehensive embodiment 1 to embodiment 4 shows that: the grid sewage treatment device in the urban sewage advanced treatment system described in the utility model can be one-stage or multi-stage, preferably two-stage coarse grid sewage treatment machine and Fine grid sewage treatment machine; the grid gap of the coarse grid sewage treatment machine is 20-30mm; the grid gap of the fine grid sewage treatment machine is 5-10mm. There are at least three types of grit chambers that can be selected, advection type grit chambers, swirl type grit chambers and aeration type grit chambers. The types of carriers that can be selected for the composite adsorbent of nanometer hydrated iron oxide include at least macroporous anion exchange resin, activated carbon, diatomaceous earth and pulverized coal.

The above are only preferred embodiments of the present utility model, but the scope of protection of the present utility model is not limited thereto. Any skilled person familiar with the art within the technical scope disclosed by the utility model can easily think of changes or Replacement should be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be determined by the protection scope defined in the claims.

Claims (9)

1. A system for advanced treatment of urban sewage, characterized in that, the advanced treatment system for urban sewage comprises a grid sewage treatment device connected in order to remove suspended solids, a grit chamber for precipitating inorganic particles, and denitrification and denitrification. Nitrogen treated anoxic pool, MBR aerobic pool, adsorption filter and disinfection pool; in, The bottom of the MBR aerobic tank is provided with a sludge outlet; The adsorption filter tank is filled with a composite adsorbent of nanometer hydrated iron oxide for further dephosphorization of sewage. the 2. The urban sewage advanced treatment system according to claim 1, wherein said grid sewage treatment device comprises a coarse grid sewage treatment machine and a fine grid sewage treatment machine; said coarse grid sewage treatment machine grid The gap between the bars is 20-30mm; the gap between the bars of the fine grid sewage treatment machine is 5-10mm. the 3 . The urban sewage advanced treatment system according to claim 1 , wherein the grit chamber is an advection type grit chamber, a swirl type grit chamber or an aeration type grit chamber. the 4. The urban sewage advanced treatment system according to claim 1, wherein the MBR aerobic tank comprises a flat MBR membrane module. the 5. The urban sewage advanced treatment system according to claim 1 or 4, wherein the sludge outlet of the MBR aerobic tank is also communicated with the anoxic tank through a pipeline; the pipeline is used to partially The sludge is returned to the anoxic tank, and the return ratio is 30%-60%. the 6 . The urban sewage advanced treatment system according to claim 1 , wherein the nanometer hydrated iron oxide includes a carrier, and the carrier is a macroporous anion exchange resin, activated carbon, diatomaceous earth or pulverized coal. the 7. The urban sewage advanced treatment system according to claim 1, characterized in that, the adsorption filter tank further comprises an input pipe for inputting a sodium hydroxide aqueous solution with a specific gravity of 2%-5%. the 8. The urban sewage advanced treatment system according to claim 1, wherein the disinfection pool is an ultraviolet disinfection pool. the 9. The urban sewage advanced treatment system according to claim 1, characterized in that, a sludge dewatering device is connected to the rear end of the sludge outlet. the

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