CN106745740B

CN106745740B - Improved composite efficient water treatment method and system for denitrification and dephosphorization

Info

Publication number: CN106745740B
Application number: CN201611217738.9A
Authority: CN
Inventors: 桂新安; 叶方清; 盛倩; 戴杨叶; 洪士杰
Original assignee: SDIC Xinkai Water Environment Investment Co Ltd
Current assignee: Xinkai Water Environment Investment Co ltd
Priority date: 2016-12-26
Filing date: 2016-12-26
Publication date: 2023-04-21
Anticipated expiration: 2036-12-26
Also published as: CN106745740A

Abstract

The invention further provides a water body treatment method for denitrification and dephosphorization, which comprises the following steps: (1) Mixing at least part of water body to be treated with sludge for pre-anoxic treatment; (2) carrying out anaerobic treatment on the water body obtained by the pre-anoxic treatment; (3) Alternately performing anoxic treatment and aerobic treatment on the water body obtained by anaerobic treatment; (4) degassing the water body obtained in the step (3); and (5) carrying out precipitation treatment on the water body obtained by the degassing treatment. The water treatment method and the system for denitrification and dephosphorization provided by the invention can optimize the water quality and have the advantages of low cost, high efficiency and the like.

Description

Improved composite efficient water treatment method and system for denitrification and dephosphorization

Technical Field

The invention relates to the field of water treatment, in particular to an improved composite efficient water treatment method and system for denitrification and dephosphorization, wherein the water treatment system can be used as an improved composite efficient denitrification and dephosphorization bioreactor.

Background

With urban development and acceleration of industrialization progress, sewage treatment becomes a hot spot environmental problem of great concern. A large amount of domestic sewage, industrial wastewater and farmland surface water runoff are collected into lake water, river, reservoir and bay water areas, so that other plants such as algae are propagated in a large amount, and water eutrophication is formed. For the countries with shortage of water resources in China, strict control of the out-of-standard discharge of nitrogen and phosphorus sewage is necessary, and the denitrification and dephosphorization technology in the prior art mainly comprises the following steps:

1) Traditional AAO

The process flow chart is shown as follows, and the biological pool is divided into an anaerobic section (A1), an anoxic section (A2) and an aerobic section (O) by an aeration device, a propeller (an anaerobic section and an anoxic section) and a reflux channel, as shown in the figure 1-1.

Within this process flow, BOD5, SS and nitrogen and phosphorus in various forms will be removed one by one. In the activated sludge of the A2O biological denitrification and dephosphorization system, the flora mainly comprises nitrifying bacteria, denitrifying bacteria and phosphorus accumulating bacteria. The waste water firstly enters an anaerobic section (A1), and the facultative anaerobic fermentation bacteria convert biodegradable macromolecular organic matters in the waste water into micromolecular fermentation products such as VFA. The phosphorus accumulating bacteria can decompose phosphorus accumulating salt stored in the bacteria body, the released energy can be used for the obligate aerobic phosphorus accumulating bacteria to maintain survival in an anaerobic environment, and the other part of energy can also actively absorb VFA and other small molecular organic matters in the environment and store the same in the bacteria body in a PHB mode. Then the wastewater enters an anoxic section (A2), and denitrifying bacteria utilize nitrate brought by the reflux of the mixed liquid in the aerobic section and biodegradable organic matters in the wastewater to perform denitrification, so that the aim of simultaneously removing carbon and nitrogen is fulfilled. The waste water enters an aeration aerobic section (O), and phosphorus accumulating bacteria not only absorb and utilize residual biodegradable organic matters in the waste water, but also decompose PHB stored in the body, and the released energy can be used for growth and propagation, and can actively absorb phosphorus dissolved in the surrounding environment and store the phosphorus in the body in the form of phosphorus accumulating salt. The concentration of dissolved phosphorus in the discharged wastewater is already quite low. After the organic matters in the aerobic section (O) are respectively utilized by phosphorus accumulating bacteria and denitrifying bacteria through the anaerobic section (A1) and the anoxic section (A2), the concentration is quite low, which is favorable for the growth and propagation of autotrophic nitrifying bacteria and the conversion of ammonia (NH4+) into NO 3-through nitrification. Although aerobic heterotrophic bacteria other than phosphorus can exist, they are severely suppressed in the anaerobic zone (A1) and insufficient in nutrition in the aerobic zone (O), and therefore are disadvantageous in competing with microorganisms of other physiological groups. In the discharged surplus sludge, as a large amount of phosphorus accumulating bacteria capable of accumulating and accumulating phosphorus salt excessively are contained, the phosphorus content in the sludge can reach more than 2.5%, so that the phosphorus removal effect can be greatly improved compared with a common aerobic activated sludge system.

2)JHB

The modification of the traditional AAO process, namely, a pre-anoxic tank is arranged in front of an anaerobic tank of the traditional AAO process, and meanwhile, the sludge in the secondary sedimentation tank flows back to the pre-anoxic tank, so that the biological principle of treating wastewater by the JHB process is basically consistent with that of the traditional AAO process.

The wastewater respectively enters the pre-anoxic tank and the anaerobic tank according to a certain distribution proportion, and the pre-anoxic tank has the function of removing a large amount of nitrate nitrogen carried by the return sludge in the form of nitrogen by using part of organic matters in the inflow water as electron donors through denitrifying bacteria in the system, so that the influence of nitrate on the phosphorus release of the anaerobic tank is reduced, and the final phosphorus removal of the system is facilitated. Meanwhile, in the pre-anoxic tank, phosphorus release (when the C/N is higher) and phosphorus absorption (when the C/N is lower, denitrification phosphorus absorption) can occur along with the organic mass of the inlet water; the mixed solution in the pre-anoxic tank and part of inflow water enter a subsequent anaerobic tank together, and phosphorus accumulating bacteria in the system synthesize storage such as PHB and the like in cells by utilizing organic matters which are easy to biodegrade, and release phosphorus; after passing through the anaerobic tank, the wastewater enters the pre-anoxic tank and is mixed with nitrifying liquid from the aerobic tank, and the stage mainly comprises two biochemical processes, namely a conventional denitrification process by using denitrifying bacteria, and a denitrification phosphorus accumulating process by using denitrifying phosphorus accumulating bacteria by using nitrate nitrogen as an electron acceptor; finally, the wastewater enters an aerobic tank, and the reaction of the wastewater and the aerobic phosphorus accumulation is consistent with the action of the traditional AAO technology.

The process flow is shown in fig. 1-2.

3) Multi-segment AO

The multistage AO technology designs a biological reaction tank as a front anaerobic zone/aerobic zone and a multistage anoxic zone, adopts a multi-point water distribution technology, distributes sewage into the front ends of the anaerobic zone and the anoxic zones respectively in a plurality of stages, and the reflux sludge completely flows back to the front end of the anaerobic zone, thereby creating an environment more suitable for growth and propagation of phosphorus accumulating bacteria, nitrifying bacteria and denitrifying bacteria, greatly enhancing the dephosphorizing and denitrifying capacity, and having the technological process shown in figures 1-3.

The process principle is as follows: in the sewage biological treatment process, the removal of total nitrogen is mainly realized by means of a denitrification process, and the necessary condition for denitrification is that nitrification is performed first. In the process of the chain reaction of nitrification and denitrification, the nitrification rate is obviously slower than the denitrification rate, and the main reason is that the proliferation rate of nitrifying bacteria is slow. Biological phosphorus removal is accomplished by means of specific physiological characteristics of phosphorus accumulating bacteria. Under anaerobic condition, the phosphorus accumulating bacteria utilize organic matters which are easy to degrade in sewage to synthesize storage matters such as poly beta-hydroxybutyric acid (PHB) and the like, and store the storage matters in cells. Under aerobic conditions, the phosphorus accumulating bacteria oxidize the intracellular stored PHB to take up phosphate from the sewage in excess and convert it into phosphorus, store it as energy in the cell, and discharge the phosphorus out of the sewage treatment system through the discharge of excess sludge. For the activated sludge process, increasing the proportion of nitrifying bacteria and phosphorus accumulating bacteria in an activated sludge system is a technical key for efficient dephosphorization and denitrification effects. According to the population advantage theory in ecology, the multistage A/O technology with the dephosphorization and denitrification functions realizes reasonable distribution of carbon sources and effective full utilization by sectional water distribution, so that a sludge concentration gradient from high to low is formed in a biological pond, meanwhile, the total quantity of organisms is increased, phosphorus accumulating bacteria, nitrifying bacteria and denitrifying bacteria are in advantages, the dephosphorization and denitrification effects are enhanced, and a novel technology which is formed by combining primary anaerobic Aerobic (AO) dephosphorization and multistage anoxic-aerobic (MAO) enhanced denitrification is formed.

4)IFAS

The IFAS process is a process (the principle is shown in the following figures 1-4) combining an attached growth biomembrane process and a suspension growth activated sludge process, specifically, suspension filler is put into the activated sludge process, pollutants in water are removed together through biomembrane on the suspension filler and the suspension activated sludge, and due to the cutting effect of the suspension filler on bubbles, the oxygen transfer efficiency in water can be improved, and the treatment effect is enhanced.

In addition, the IFAS technology enables the filler to be suspended in the reactor in the modes of aeration disturbance, liquid backflow and the like, and as the biomass fixed on the filler does not increase the concentration of the mixed liquor of the activated sludge and the growth of the biological film can reduce the SVI of the system, the performance of a downstream sedimentation tank is not negatively affected by the increase of the solid load in the activated sludge reactor, and the performance of the downstream sedimentation tank can be improved to a certain extent.

The multistage A/O process has obvious advantages compared with CAST because of smaller tank capacity, lower operation energy consumption and simple operation and management, but the multistage AO is not provided with independent anaerobic sections in the process, and effluent is discharged after the sewage well is alternately anoxic and aerobic, so that a proper living environment is not provided for phosphorus accumulating bacteria in the process, and the biological phosphorus removal effect of the process is poor; meanwhile, the water power flow state of plug flow is presented on the whole, so that the problems of uneven distribution of dissolved oxygen, poor impact load bearing capacity of each reaction section and the like are easily caused; and as can be seen from the foregoing, the reduction in cell capacity is limited by the change in the number of stages.

On the basis of the traditional AAO function, three process advantages (the JHB efficient dephosphorization, the IFAS small occupied area, the improvement of the concentration of the activated sludge mixed liquor, the sludge reduction, the improvement of the sludge sedimentation performance, no increase of the secondary sedimentation tank load and the strong buffer capacity, the multi-section AO sludge concentration, the full utilization of carbon sources, the high denitrification efficiency, the strong impact load resistance, the low running cost, the low engineering investment and the like) of the JHB are fully combined, and raw water of a town sewage treatment plant is subjected to biochemical treatment to achieve the better effluent quality.

Although the traditional denitrification and dephosphorization technologies have respective characteristics, the technologies have certain defects, so that the high efficiency and stability of the technology are restricted, and a plurality of processes comprise the backflow of multiple sludge and mixed liquor, so that the complexity of the system is increased, and the capital construction and operation cost are greatly increased. Therefore, further development and development of biological nitrogen and phosphorus removal are still necessary, and the level of biological nitrogen and phosphorus removal is continuously improved.

Disclosure of Invention

In view of the above-described drawbacks of the prior art, an object of the present invention is to provide a water treatment method and system for denitrification and dephosphorization, which solve the problems of the prior art.

The first aspect of the invention provides a water treatment method for denitrification and dephosphorization, comprising the following steps:

(1) Mixing at least part of water body to be treated with sludge to perform pre-anoxic treatment, wherein the concentration of dissolved oxygen in the water body in the pre-anoxic treatment is less than or equal to 0.5mg/L;

(2) Anaerobic treatment is carried out on the water body obtained by the pre-anoxic treatment, and the concentration of dissolved oxygen in the water body in the anaerobic treatment is less than or equal to 0.2mg/L;

(3) Alternately carrying out anoxic treatment and aerobic treatment on the water body obtained by anaerobic treatment, wherein the alternating times are more than one time, the concentration of dissolved oxygen in the water body in the anoxic treatment is less than or equal to 0.5mg/L, the concentration of dissolved oxygen in a reaction system in the aerobic treatment is 2-4 mg/L, and in the aerobic treatment of at least part times, filler is added into the water body during treatment and/or at least part of water body to be treated is introduced during treatment;

(4) Degassing the water body obtained in the step (3), and regulating the concentration of dissolved oxygen in the water body to 0.2-0.5 mg/L;

(5) And (3) carrying out precipitation treatment on the water body obtained by the degassing treatment, wherein at least part of sludge obtained by precipitation is reused for pre-anoxic treatment.

In the pre-anoxic treatment process of the water treatment method for denitrification and dephosphorization, the water to be treated can be partially subjected to the pre-anoxic treatment according to the proportion, in the pre-anoxic treatment process, the water to be treated is mixed with the return sludge (the sludge obtained from the precipitation treatment), organic matters in the inlet water are used as a carbon source for denitrification, nitrate brought by the return sludge is removed, the adverse effect of nitrate nitrogen on anaerobic dephosphorization is further eliminated, and the biological dephosphorization capacity in the subsequent treatment process is improved.

The water body to be treated can be a water body with higher nitrogen and phosphorus content, for example, TN (total nitrogen content) in the water body to be treated can be 30-80 mg/L, and TP (total phosphorus content) can be 3-15 mg/L. For another example, in the water body to be treated, COD _Cr (use of Potassium dichromate (K) ₂ Cr ₂ O ₇ ) Oxygen consumption measured as oxidant) may be 200 to 1000mg/L; BOD (BOD) ₅ (the value of BOD (biochemical oxygen demand) for 5 days) can be 100-400 mg/L; NH (NH) ₃ -N (ammonia nitrogen content in water) can be 20-45 mg/L; SS (the amount of suspended solids in a body of water) may be 140-500 mg/L.

In general, the amount of water to be treated used in the pre-anoxic treatment and the amount of water to be treated used in each aerobic treatment can be adjusted by one skilled in the art according to the dissolved oxygen concentration in the pre-anoxic treatment and/or in each aerobic treatment and/or in the water during each anoxic treatment. In some embodiments of the present invention, the volume ratio of the amount of the water to be treated used in the pre-anoxic treatment to the total amount of the water to be treated used in each aerobic treatment process may be 1: 5-9, the amount of the water body to be treated used in each aerobic treatment process can be adjusted according to the needs, for example, when the concentration of the target treatment object (for example, TN) is lower, more water bodies to be treated can be introduced, and when the concentration of the target treatment object (for example, TN) is higher, less water bodies to be treated can be introduced.

In some embodiments of the invention, the pre-anoxic treatment has a sludge load of 0.05 to 0.15kgBOD ₅ /(kgMLSS.d). One skilled in the art can select an appropriate type of sludge based on the process conditions (e.g., dissolved oxygen concentration in the body of water, sludge loading, etc.) in the treatment process.

In some embodiments of the invention, the concentration of sludge in the body of water is 8000-14000 mg/L in the pre-anoxic treatment.

In some embodiments of the invention, the pre-anoxic treatment agitates the body of water, preferably submerged, preferably at an agitation strength of 4-5W/m ³ 。

The submerged stirring generally refers to a stirring device (e.g., a submerged propeller) used in stirring, and the submerged stirring device can stir a water body and simultaneously push the water body to flow in a certain direction.

In some embodiments of the invention, the hydraulic retention time in the pre-anoxic treatment is between 0.3 and 1 hour.

In some embodiments of the invention, the concentration of dissolved oxygen in the reaction system is 0.2-0.5 mg/L in the pre-anoxic treatment.

In the anaerobic treatment process of the water treatment method for denitrification and dephosphorization, the water subjected to the pre-anoxic treatment can be further subjected to anaerobic treatment and can be mixed with at least part of water to be treated, so that phosphorus in the water can be released, the concentration of P (phosphorus) in the water can be increased, and the concentration of BOD in sewage can be reduced due to the absorption of soluble organic matters by microbial cells; in addition, NH ₃ N is partially removed by cell synthesis, which results in NH in the wastewater ₃ The concentration of-N canTo decrease and NO ₃ The content of N may not vary significantly.

In some embodiments of the invention, the anaerobic treatment is performed by stirring the water, preferably submerged stirring, preferably at a stirring intensity of 4-5W/m ³ 。

In some embodiments of the invention, the anaerobic treatment has a hydraulic retention time of 0.5 to 2 hours.

In some embodiments of the invention, the pre-anoxic treated water body is mixed with at least a portion of the water body to be treated for anaerobic treatment.

In some embodiments of the invention, the anaerobic treatment is performed on the supernatant of the body of water obtained from the pre-anoxic treatment.

In the anoxic treatment process of the water treatment method for denitrification and dephosphorization, the water can be further subjected to anoxic treatment after being subjected to anaerobic treatment, and the denitrification and denitrification can be performed by using the organic matters in the raw sewage as a carbon source, so that at least part of the organic matters are degraded. The water body can be further subjected to anoxic treatment after being subjected to aerobic treatment, so that the water body containing higher nitrate nitrogen after being subjected to aerobic treatment can be mixed with at least part of the water body to be treated, denitrifying bacteria can utilize organic matters in the water body to be treated as carbon sources again for denitrification, and at least part of the organic matters in the water body to be treated are degraded again. The water body obtained by the anoxic treatment can be further subjected to aerobic treatment.

In some embodiments of the invention, the anoxic treatment is performed by stirring the water body, preferably submerged stirring, preferably with a stirring strength of 1-3W/m ³ 。

In some embodiments of the invention, the hydraulic retention time in the anoxic treatment may be in the range of 0.5 to 5 hours, and the hydraulic retention time generally refers to the sum of the hydraulic retention times during each anoxic treatment. The hydraulic residence time during each anoxic treatment can be adjusted by one skilled in the art according to the content of the target treatment (e.g., TN, etc.). Generally, when the target treatment concentration is high, the hydraulic retention time is long.

In some embodiments of the invention, the denitrification load value (denitrification rate) of the water body is 0.03-0.06 kgNO in the anoxic treatment ₃ -N/kgMLSS.d。

In some embodiments of the invention, the concentration of dissolved oxygen in the anoxic treatment is 0.2 to 0.5mg/L.

In the aerobic treatment process of the water treatment method for denitrification and dephosphorization, the water subjected to anoxic treatment can be further subjected to aerobic treatment, so that organic matters in the water can be biochemically degraded by high-concentration microorganisms (for example, the concentration of the microorganisms can be 10000-15000 mg/L) in the mixed liquid and suspended filler area. At the same time, organic nitrogen and the like can be ammoniated and nitrified to lead NH ₃ The concentration of N can be continuously reduced, and the phosphorus accumulating bacteria can also take excessive P in the process, so that the P content is reduced at a higher speed.

In some embodiments of the invention, in the aerobic treatment, the water body is aerated and stirred, and the aeration intensity is 4-6 m ³ /m ² .h。

Aeration stirring generally refers to aeration of a water body through an aeration device, and can enable the water body to form convection at the same time, so that the effect of stirring the water body is achieved.

In some embodiments of the invention, the hydraulic retention time in the aerobic treatment is 3.5 to 13 hours, and the hydraulic retention time generally refers to the sum of hydraulic retention times in each aerobic treatment process. Those skilled in the art can vary the amount of the target treatment (e.g., COD _Cr Etc.), the hydraulic retention time in each aerobic treatment process is adjusted. Generally, when the target treatment concentration is high, the hydraulic retention time is long.

In some embodiments of the invention, the filler is made of high density polyethylene (High Density Polyethylene, HDPE) in the aerobic treatment. For example, the high density polyethylene may have a density of 94 to 98kg/m ³ 。

In some embodiments of the present invention, the packing has a bulk specific gravity of 94 to 98kg/m in the aerobic treatment ³ 。

In some embodiments of the invention, the specific surface area of the filler in the aerobic treatment>500m ² /m ³ 。

In some embodiments of the invention, the filler is located in the last 4/5 section of the body of water in the direction of travel of the body of water in the aerobic treatment.

In some embodiments of the invention, the filler is located in the suspended filler zone in the aerobic treatment.

In some embodiments of the invention, the packing fraction is 30 to 60%.

The suspended packing region may be of various structures and/or devices capable of containing packing and passing a body of water, for example, the suspended packing region may be a suspended packing region formed by a suspended packing entrapment device, which may be, for example, a porous entrapment mesh or the like.

In the degassing treatment process of the water treatment method for denitrification and dephosphorization, the water subjected to at least one alternating anoxic treatment and aerobic treatment can be further subjected to the degassing treatment, so that excessive dissolved oxygen carried in the water can be reduced, and after sludge is refluxed, the consumption of carbon sources for pre-anoxic treatment and subsequent denitrification treatment can be reduced.

In some embodiments of the invention, the deaeration treatment is performed on a body of water, preferably submerged agitation.

In the precipitation treatment process of the water treatment method for denitrification and dephosphorization provided by the invention, the water subjected to the degassing treatment can be further subjected to the precipitation treatment, so that mud-water separation in the water can be realized, purified water (for example, supernatant liquid) obtained by separation can be discharged, at least part of concentrated sludge obtained by precipitation is returned to the pre-anoxic zone, and the rest of the concentrated sludge can further enter a sludge concentration and dehydration system.

In some embodiments of the present invention, 50% or more of the sludge obtained by the precipitation is used for the pre-anoxic treatment, and preferably, the remaining sludge is concentrated and dehydrated.

In some embodiments of the invention, the surface loading in the precipitation treatment is 0.7 to 1.8m3/m2.H.

In some embodiments of the invention, the supernatant obtained by the precipitation treatment meets the primary water quality index requirements of the first-level A standard of GB 18918-2002.

The second aspect of the invention provides a water body treatment system for denitrification and dephosphorization, which comprises a pre-anoxic treatment device, an anaerobic treatment device, an anoxic and aerobic alternate treatment device, a degassing treatment device and a sedimentation treatment device which are sequentially in fluid communication, wherein the anoxic and aerobic alternate treatment device comprises more than one group of anoxic treatment devices and aerobic treatment devices which are alternately in fluid communication, the water body treatment system also comprises a water inlet pipeline which is in fluid communication with the pre-anoxic treatment device and/or at least part of the aerobic treatment devices, a filler is arranged in the aerobic treatment device, and the sedimentation treatment device is in fluid communication with the pre-anoxic treatment device through a sludge return pipeline.

The fluid communication generally refers to the introduction of fluid from one device to another device between the devices. The fluid may typically be, for example, a gas, a liquid, or the like.

In some embodiments of the invention, the pre-anoxic treatment device is provided with sludge with a sludge load of 0.05-0.15 kg BOD ₅ /(kgMLSS.d)。

In some embodiments of the invention, the concentration of the sludge relative to the water body in the pre-anoxic treatment device is 8000-14000 mg/L.

In some embodiments of the invention, the pre-anoxic treatment device is provided with a stirring device, preferably a submersible stirring device.

In some embodiments of the present invention, a diversion partition is further provided in the pre-anoxic treatment device.

In some embodiments of the invention, the pre-anoxic treatment device is in fluid communication with a water intake conduit.

In some embodiments of the invention, the anaerobic treatment device is provided with a stirring device, preferably a submersible stirring device.

In some embodiments of the invention, the anaerobic treatment device is in fluid communication with a water intake conduit.

In some embodiments of the invention, the anaerobic treatment device is in fluid communication with the pre-anoxic treatment device through an overflow device or a water passing hole.

In some embodiments of the invention, a diversion partition is further provided in the anaerobic treatment device.

In some embodiments of the invention, the anoxic treatment device is provided with a stirring device, preferably a submersible stirring device.

In some embodiments of the invention, an aeration device is provided in the anoxic treatment device.

In some embodiments of the invention, the anoxic treatment device is in fluid communication with a water intake conduit.

In some embodiments of the invention, the aerobic treatment device is provided with an aeration device and/or a stirring device, preferably an aeration stirring device.

In some embodiments of the invention, the material of the filler in the aerobic treatment device is high-density polyethylene.

In some embodiments of the present invention, the aerobic treatment device has a bulk specific gravity of 94 to 98kg/m ³ 。

In some embodiments of the invention, the aerobic treatment device has a specific surface area of the filler>500m ² /m ³ 。

In some embodiments of the invention, the filler is located at the rear 4/5 section of the aerobic treatment device according to the travelling direction of the water body.

In some embodiments of the invention, the packing is located within a suspended packing zone, preferably the suspended packing zone is comprised of suspended packing entrapment devices.

In some embodiments of the present invention, the packing ratio in the aerobic treatment apparatus is 30 to 60%.

In some embodiments of the invention, a diversion partition wall is further arranged in the aerobic treatment device.

In some embodiments of the invention, the degassing treatment device is provided with a stirring device, preferably a submersible stirring device.

In some embodiments of the invention, a sludge discharge conduit is also included, which is in fluid communication with the sedimentation treatment device, preferably a sludge concentrating and dewatering treatment device is also included, which is in fluid communication with the sedimentation treatment device through the sludge discharge conduit.

In some embodiments of the invention, the sedimentation treatment device comprises a water outlet pipe, and an overflow device is arranged on the water outlet pipe.

As described above, compared with the prior art, the water treatment method and system for denitrification and dephosphorization provided by the invention have the following remarkable characteristics:

(1) The water treatment method and the system provided by the invention are provided with the pre-denitrification process section, so that the nitrate content in the return sludge can be reduced, and the anaerobic environment of the anaerobic section can be better maintained, thereby being more beneficial to dephosphorization, and the quality of the treated main effluent water can reach below the first-level A standard of pollutant emission standard of urban sewage treatment plant (GB 18918-2002);

(2) The method adopts various treatment processes, and ensures that the operation mode of the reactor is more flexible and the denitrification and dephosphorization efficiency is high by the optimized control of the reaction conditions such as the multistage distribution of pollutants, hydraulic flow state and the like;

(3) The specific microorganism carrier is adopted, so that the impact resistance of the reactor is improved, the sludge settling performance is enhanced, the output of residual sludge is reduced, the effective tank capacity and engineering investment are reduced, the effective tank capacity is reduced by about 40%, and the engineering investment is reduced by about 4-8%;

(4) The optimized design of different pool bodies and pipeline system structural forms is adopted, so that the flow state of the reactor is smoother, and the energy consumption is reduced; the microporous aeration equipment is adopted, the power consumption is far lower than that of an oxidation ditch process or a mesoporous aeration system, and the contradiction between oxygenation and stirring is solved by combining plug flow; compared with the conventional process, the method can save energy consumption by about 0.05 to 0.1kW.h/m ³ 。

Drawings

FIG. 1-1 shows a flow chart of an A2/O process.

FIGS. 1-2 show a JHB process flow diagram.

FIGS. 1-3 show a multi-stage AO process flow diagram.

FIGS. 1-4 show a flow chart of an IFAS process.

FIG. 2 shows a schematic overall process flow of the present invention.

Fig. 3 is a schematic structural diagram of an embodiment of the present invention.

Description of element reference numerals

101. Pre-anoxic treatment device

102. Anaerobic treatment device

103. Anaerobic and aerobic alternate treatment device

104. Anoxic treatment device

1041. First anoxic treatment device

104n nth anoxic treatment device

105. Aerobic treatment device

1051. First aerobic treatment device

105 n-th aerobic treatment device

106. Degassing treatment device

107. Sedimentation treatment device

108. Water inlet pipeline

109. Water outlet pipeline

110. Sludge return pipeline

111. Sludge discharge pipeline

1. Pre-anoxic zone

2. Anaerobic zone

3. First anoxic zone

4. First aerobic zone

5. Second anoxic zone

6. Second aerobic zone

7. Degassing zone

8. Precipitation zone

9. Water inlet channel

10. Water outlet

11. Mud outlet channel

11a return sludge canal

11b excess sludge discharge canal

12. Diversion partition wall of pre-anoxic zone

13. Flow guide partition wall between pre-anoxic zone and anaerobic zone

14. Anaerobic zone diversion partition wall

15. Partition wall between anaerobic zone and first anoxic zone

16. First anoxic zone flow guiding partition wall

17. Partition wall between first anoxic zone and first aerobic zone

18. First aerobic zone flow guiding partition wall

19. Partition wall between first aerobic zone and second anoxic zone

20. Second anoxic zone flow guiding partition wall

21. Partition wall between second anoxic zone and second aerobic zone

22. Second aerobic zone flow guiding partition wall

23. Partition wall of second aerobic zone and degassing zone

24. Partition wall between degassing zone and sedimentation zone

25. Diversion hole of pre-anoxic zone

26. Diversion hole of pre-anoxic zone

27. Water hole from pre-anoxic zone to anaerobic zone

28. Anaerobic zone diversion hole

29. Anaerobic zone diversion hole

30. Water passing hole from anaerobic zone to first anoxic zone

31. First anoxic zone diversion hole

32. First anoxic zone diversion hole

33. Water holes from the first anoxic zone to the first aerobic zone

34. First aerobic zone diversion hole

35. First aerobic zone diversion hole

36. Water passing holes from first aerobic zone to second anoxic zone

37. Second anoxic zone diversion hole

38. Second anoxic zone diversion hole

39. Water holes from the second anoxic zone to the second aerobic zone

40. Second aerobic zone diversion hole

41. Second aerobic zone diversion hole

42. Water outlet hole from second aerobic zone to degassing zone

43. Water outlet hole from degassing zone to precipitation zone

44. Suspension filler

45. Suspension filler interception device

46. Submersible mixer

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.

It should be understood that the process equipment or devices not specifically identified in the examples below are all conventional in the art.

Furthermore, it is to be understood that the reference to one or more method steps in this disclosure does not exclude the presence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise indicated; it should also be understood that the combined connection between one or more devices/means mentioned in the present invention does not exclude that other devices/means may also be present before and after the combined device/means or that other devices/means may also be interposed between these two explicitly mentioned devices/means, unless otherwise indicated. Moreover, unless otherwise indicated, the numbering of the method steps is merely a convenient tool for identifying the method steps and is not intended to limit the order of arrangement of the method steps or to limit the scope of the invention in which the invention may be practiced, as such changes or modifications in their relative relationships may be regarded as within the scope of the invention without substantial modification to the technical matter.

As shown in fig. 2, the present invention further provides a water treatment system for denitrification and dephosphorization, which comprises a pre-anoxic treatment device 101, an anaerobic treatment device 102, an anoxic and aerobic alternative treatment device 103, a degassing treatment device 106 and a sedimentation treatment device 107 which are sequentially in fluid communication, wherein the anoxic and aerobic alternative treatment device 103 comprises more than one group of anoxic treatment devices 104 and aerobic treatment devices 105 which are alternately in fluid communication, for example, n times of alternation can be n times, n is a positive integer, and the specific times of alternation can be 1 time, 2 times, 3 times, 4 times or more. The water treatment system further comprises a water inlet pipeline 108, wherein the water inlet pipeline 108 is in fluid communication with the pre-anoxic treatment device 104 and/or at least part of the aerobic treatment device 105, the aerobic treatment device 105 is provided with a filler, and the sedimentation treatment device 107 is in fluid communication with the pre-anoxic treatment device 101 through a sludge return pipeline 110.

In the water treatment system provided by the present invention, the pre-anoxic treatment device 101 may be various reaction vessels available in the art for water treatment, such as a reaction tank, etc., and the pre-anoxic treatment device 101 may be further provided with a stirring device, such as a submersible stirring device (specifically, may be provided withIs a submersible stirrer, etc.), thereby stirring the water body, enabling the water body to be uniformly distributed and flow in a certain direction, and the stirring strength can be 4-5W/m ³ . The pre-anoxic treatment device 101 may further be provided with a guide partition wall, which may generally partition a space inside the device, so that the water body may flow in a certain direction.

In the pre-anoxic treatment device 101 of the water treatment system provided by the invention, the water to be treated can be partially introduced into the pre-anoxic treatment device 101 in proportion and subjected to pre-anoxic treatment, in the pre-anoxic treatment process, the water to be treated is mixed with return sludge (the sludge obtained from precipitation treatment), organic matters in the inlet water are used as carbon sources for denitrification, nitrate brought by the return sludge is removed, thereby eliminating adverse effects of nitrate nitrogen on anaerobic dephosphorization and improving biological dephosphorization capability in the subsequent treatment process. In the pre-anoxic treatment device, the concentration of dissolved oxygen in the water body can be less than or equal to 0.5mg/L, and the concentration of dissolved oxygen in the water body can also be 0.2-0.5 mg/L. The pre-anoxic treatment device can be provided with sludge, and the load of the used sludge can be 0.05-0.15 kg BOD ₅ And (kg MLSS. D), wherein the concentration of the sludge relative to the water body is 8000-14000 mg/L in use. In the pre-anoxic treatment device, the hydraulic retention time can be generally 0.3 to 1h.

In the water treatment system provided by the invention, the anaerobic treatment device 102 can be various reaction vessels which can be used for water treatment in the field, such as a reaction tank, a reaction pot and the like, and the anaerobic treatment device 102 can be also provided with a stirring device, such as a diving stirring device (particularly a diving stirrer and the like), so that the water can be stirred, the water can be uniformly distributed and flows in a certain direction, and the stirring strength can be 4-5W/m ³ . The anaerobic treatment device 102 may also be in fluid communication with a water intake conduit 108 such that the pre-anoxic treated water body may be mixed with at least a portion of the water body to be treated for anaerobic treatment. The anaerobic treatment device 102 can be in fluid communication with the pre-anoxic treatment device 101 through an overflow device or a water passing hole, thereby enabling pre-anoxic treatmentThe supernatant of the treated water body may be introduced into an anaerobic treatment device 102, which may be, for example, a weir or the like, for further anaerobic treatment. The anaerobic treatment device 102 may further be provided with a guide partition wall, which may generally partition a space inside the device, so that a water body may flow in a certain direction.

In the anaerobic treatment device 102 of the water treatment system provided by the invention, the water subjected to the pre-anoxic treatment can be further introduced into the anaerobic treatment device 102 to be subjected to anaerobic treatment, and at least part of the water to be treated can be introduced into the treatment process to be mixed, so that phosphorus in the water can be released, the concentration of P (phosphorus) in the water can be increased, and the concentration of BOD in sewage can be reduced due to the absorption of soluble organic matters by microbial cells; in addition, NH ₃ N is partially removed by cell synthesis, which results in NH in the wastewater ₃ The concentration of-N can be reduced while NO ₃ The content of N may not vary significantly. In the anaerobic treatment device 102, the concentration of dissolved oxygen in the water body can be less than or equal to 0.2mg/L, and the hydraulic retention time can be 0.5-2 h.

In the water treatment system provided by the invention, the anoxic treatment device 104 can be various reaction vessels which can be used for water treatment in the field, such as a reaction tank, a reaction pot and the like, and the anoxic treatment device 104 can be also provided with a stirring device, such as a diving stirring device (particularly a diving stirrer and the like), so that the water can be stirred, the water can be uniformly distributed and flows in a certain direction, and the stirring strength is 1-3W/m ³ . The anoxic treatment device 104 may be further provided with an aeration device (e.g., an aerator, etc.), so that the oxygen content in the water body may be adjusted, and the number of aeration devices (aeration intensity) in the anoxic treatment device 104 may be generally 10 to 20% of the number of aeration devices (aeration intensity) in the aerobic treatment device 105.

In the anoxic treatment device 104 of the water treatment system provided by the invention, the water inlet of the anoxic treatment device of the first stage (for example, the first anoxic treatment device 1041) is generally connected with the anaerobic treatment device 102 and is subjected to anaerobismThe oxygen-treated water may be further introduced into the anoxic treatment device 104 to undergo anoxic treatment, and denitrification may be performed using the organic matters in the raw sewage as a carbon source, such that at least a portion of the organic matters are degraded. In the anoxic treatment device 104 of the water treatment system provided by the invention, the water inlets of anoxic treatment devices (for example, 1042-104 n) except the anoxic treatment device of the first stage are usually connected with the water outlets of the aerobic treatment devices 105 corresponding to the previous stage (for example, 1042 corresponds to 1051 and 1043 corresponds to 1052), and the water body can be further subjected to anoxic treatment after being subjected to aerobic treatment, so that the water body containing higher nitrate nitrogen after being subjected to aerobic treatment can be mixed with at least part of water body to be treated, denitrifying bacteria can utilize organic matters in the water body to be treated again as carbon sources to perform denitrification, and at least part of organic matters in the water body to be treated are degraded again. The water body obtained by the anoxic treatment can be further subjected to aerobic treatment. In the anoxic treatment device 104, the hydraulic retention time may be generally adjusted according to the concentration of the target substance, for example, the hydraulic retention time may be 0.5 to 5 hours, and the hydraulic retention time generally refers to the sum of hydraulic retention times during each anoxic treatment. The hydraulic residence time during each anoxic treatment can be adjusted by one skilled in the art according to the content of the target treatment (e.g., TN, etc.). Generally, when the target treatment concentration is high, the hydraulic retention time is long. In the anoxic treatment device, the denitrification load value of the water body can be 0.03-0.06 kgNO ₃ N/kg MLSS. D, the concentration of dissolved oxygen may be 0.2-0.5 mg/L.

In the water treatment system provided by the invention, the aerobic treatment device 105 can be various reaction vessels which can be used for water treatment in the field, such as a reaction tank, a reaction pot and the like, and the aerobic treatment device 105 can also be an aeration device and/or a stirring device, so that the water can be aerated and/or stirred, and the uniform distribution of the water can be ensured while the water is oxygenated. For example, the water body may be stirred by aeration using an aeration stirring device such as an aerator with an aeration intensity of 4 to 6m ³ /m ² H. By a means ofThe aeration agitation device is usually positioned to cooperate with the filler, and may be, for example, at or around the location where the filler is disposed. The aeration agitation device is typically located at a distance from the bottom of the aerobic treatment device 105. The aerobic treatment device 105 may also be provided with a diversion partition wall, which may generally partition the space inside the device, so that the water body may flow in a certain direction. The aerobic treatment device 105 may also be provided with a suspended filler zone, wherein the filler is located in the rear 4/5 section of the water body (for example, the front 1/5 section is not provided with the suspended filler zone, and the rear 4/5 section is the suspended filler zone) or may be located in the 2/5-4/5 section of the water body (for example, the front 2/5 section is not provided with the suspended filler zone, 2/5-4/5 is the suspended filler zone, and the last 1/5 section is not provided with the suspended filler zone), the suspended filler zone may be formed by a suspended filler interception device, the suspended filler zone may be various structures and/or devices capable of containing the filler and allowing the water body to pass through, for example, the suspended filler zone may be a suspended filler interception device formed by a suspended filler interception device, the suspended filler interception device may be a porous interception net, for example, the aperture of the interception net may be 8mm±0.5mm, the center distance of the interception net may be 10mm±0.5mm, and the mesh shape of the interception net may be round or square.

In the aerobic treatment device 105 of the water treatment system provided by the invention, the water inlet of each stage of the aerobic treatment device 105 is usually connected with the water outlet of the anoxic treatment device 104 corresponding to the previous stage (for example, 1051 corresponds to 1041 and 1052 corresponds to 1042), the water subjected to anoxic treatment can be further introduced into the aerobic treatment device 105 to be subjected to aerobic treatment, so that organic matters in the water can be biochemically degraded by high-concentration microorganisms in the mixed liquid and suspended filler area. At the same time, organic nitrogen and the like can be ammoniated and nitrified to lead NH ₃ The concentration of N can be continuously reduced, and the phosphorus accumulating bacteria can also take excessive P in the process, so that the P content is reduced at a higher speed. In the aerobic treatment device 105, the hydraulic retention time can be generally adjusted according to the concentration of the target substance, for example, the hydraulic retention time can be 3.5 to 13 hours, and the hydraulic retention time is generally referred to asThe sum of the hydraulic retention time in each aerobic treatment process. Those skilled in the art can vary the amount of the target treatment (e.g., COD _Cr Etc.), the hydraulic retention time in each aerobic treatment process is adjusted. Generally, when the target treatment concentration is high, the hydraulic retention time is long. In the aerobic treatment device 105, the filler may be made of high-density polyethylene, and the bulk specific gravity of the filler may be 94 to 98kg/m ³ The specific surface area of the filler is generally>500m ² /m ³ . The shape of the filler is not particularly limited, and for example, the particle diameter of the filler may be 25 mm.+ -. 0.5mm, the wall thickness of the filler may be 0.4 mm.+ -. 5%, and the length of the filler may be 10 m.+ -. 0.5mm. The filler is usually positioned at the rear 4/5 section of the water body of the aerobic treatment device according to the advancing direction of the water body, and can also be positioned at the 2/5-4/5 section of the water body. The packing may generally be located in a suspended packing zone with a packing loading of 30 to 60%. The packing ratio of the packing generally refers to the percentage of the volume of the body of water that is filled.

In the water treatment system provided by the invention, the degassing treatment device 106 may be various reaction vessels available in the art for water treatment, for example, may be a reaction tank, a reaction pot, etc., and the degassing treatment device 106 may also be provided with a stirring device, for example, may be a submersible stirring device (specifically, may be a submersible stirrer, etc.), so that the water can be stirred, so that the water can be uniformly distributed and flow in a certain direction.

In the degassing treatment device 106 of the water treatment system provided by the invention, the water subjected to at least one alternating anoxic treatment and aerobic treatment can be further introduced into the degassing treatment device 106 to be subjected to degassing treatment, so that excessive dissolved oxygen carried in the water can be reduced, and after sludge is returned, carbon source consumption for pre-anoxic treatment and subsequent denitrification treatment can be reduced.

In the water treatment system provided by the present invention, the sedimentation treatment device 107 may be various reaction vessels that can be used for water treatment in the field, for example, a reaction tank, etc. The system may also include a sludge discharge conduit 111, the sludge discharge conduit 111 may be in fluid communication with the sedimentation treatment device 107, a portion of the sludge may be directed into the pre-anoxic treatment device 101, and the remaining sludge may be directed out of the sedimentation treatment device 107. The water treatment system may further include a sludge concentration and dehydration treatment device, which may be, for example, a sludge dehydrator or the like, which may be in fluid communication with the sedimentation treatment device 107 through a sludge discharge pipe 111 so as to dehydrate sludge drawn out of the sedimentation treatment device 107. The sedimentation treatment device 107 generally comprises a water outlet conduit 109, wherein the water outlet conduit 109 may be provided with overflow means, such as a weir or the like, so that supernatant resulting from the sedimentation treatment may be led out of the sedimentation treatment device 107.

In the sedimentation treatment device 107 of the water treatment system provided by the invention, the water subjected to the degassing treatment can be further introduced into the sedimentation treatment device 107 to be subjected to the sedimentation treatment, and the surface load is 0.7-1.8 m ³ /m ² .h。

In the invention, the detection method for the content of each index is as follows:

TN: potassium persulfate-ultraviolet spectrophotometry;

TP: digestion of potassium persulfate;

COD _Cr : potassium dichromate process;

BOD ₅ : standard dilution method;

NH ₃ -N: a Nahner reagent photometry;

SS: weight method.

Example 1

FIG. 3 shows an embodiment of the present invention, a modified composite high efficiency denitrification and dephosphorization bioreactor process as shown in FIG. 3, the reactor comprising: the pre-anoxic zone 1 and the anaerobic zone 2, the first anoxic zone 3, the first aerobic zone 4 (containing suspended filler zone), the second anoxic zone 5, the second aerobic zone 6 (containing suspended filler zone), the degassing zone 7, the sedimentation zone 8, the water inlet channel 9, the water outlet 10, the sludge outlet channel 11 (comprising a return sludge channel 11a and a surplus sludge discharge channel 11 b); the whole reactor is rectangular, and each reaction is rectangular; an inlet weir and a control gate are respectively arranged on the inlet canal 9 to distribute sewage to the pre-anoxic zone 1, the anaerobic zone 2, the first anoxic zone 3 and the second anoxic zone 5; the pre-anoxic zone 1 is separated by a pre-anoxic zone guide partition wall 12, water flow is communicated with the pre-anoxic zone guide hole 26 through a pre-anoxic zone guide hole 25, and a submersible stirrer 46 is arranged in the pre-anoxic zone for stirring and pushing; the anaerobic zone 2 is separated by an anaerobic zone diversion partition 14, water flow is communicated with the anaerobic zone diversion hole 29 by an anaerobic zone diversion hole 28, and a submersible stirrer 46 is arranged in the anaerobic zone for stirring and pushing; the pre-anoxic zone 1 and the anaerobic zone 2 are separated by a flow guide partition wall 13 between the pre-anoxic zone and the anaerobic zone, the anaerobic zone 2 and the first anoxic zone 3 are separated by a partition wall 15 between the anaerobic zone and the anoxic zone 1, the pre-anoxic zone 1 and the anaerobic zone 2 are communicated through a pre-anoxic zone to anaerobic zone water hole 27, and the water body of the anaerobic zone 2 can be introduced into the first anoxic zone 3 through an anaerobic zone to first anoxic zone water hole 30; the first anoxic zone 3 is separated by the first anoxic zone guide partition wall 16, water flow is communicated with the first anoxic zone guide hole 32 through the first anoxic zone guide hole 31, a submersible stirrer 46 is arranged in the first anoxic zone to stir and push, and a micropore aeration device (not shown) can be arranged in the first anoxic zone to control the oxygen content of the water body; the first anoxic zone 3 and the first aerobic zone 4 are separated by a partition wall 17 between the first anoxic zone and the first aerobic zone, and the first anoxic zone 3 is communicated with the first aerobic zone 4 through a water hole 33 from the first anoxic zone to the first aerobic zone; the first aerobic zone 4 is separated by a first aerobic zone diversion partition 18, and water flow is communicated with a first aerobic zone diversion hole 35 through a first aerobic zone diversion hole 34 and circularly flows around the first aerobic zone diversion partition 18; a suspended filler 44 and a microporous aeration device (not shown) are arranged in the first aerobic zone 4, so that oxygenation and stirring can be carried out on a water body, and the suspended filler 44 is fixed in a designated area through a suspended filler interception device 45; the first aerobic zone 5 and the second anoxic zone 6 are separated by a partition wall 21 between the second anoxic zone and the second aerobic zone, and the sewage in the first aerobic zone 6 is communicated with the second anoxic zone 5 through a water hole 39 from the second anoxic zone to the second aerobic zone; the second anoxic zone 5 is separated by a second anoxic zone diversion partition wall 20, water flows are communicated with the second anoxic zone diversion holes 38 through second anoxic zone diversion holes 37, a submersible stirrer 46 is arranged in the second anoxic zone for stirring and pushing, and a micropore aeration device (not shown) can be arranged in the second anoxic zone for controlling the oxygen content of the water body; the second anoxic zone 5 and the second aerobic zone 6 are separated by a partition wall 21 between the second anoxic zone and the second aerobic zone, and the second anoxic zone 5 is communicated with the second aerobic zone 6 through a second anoxic zone to second aerobic zone water hole 39; the second aerobic zone 6 is separated by a second aerobic zone diversion partition wall 22, and water flow is communicated with a second aerobic zone diversion hole 41 through a second aerobic zone diversion hole 40 and circularly flows around the second aerobic zone diversion partition wall 22; a suspended filler 44 and a microporous aeration device (not shown) are arranged in the second aerobic zone 6, so that oxygenation and stirring can be carried out on the water body, and the suspended filler 44 is fixed in a designated area through a suspended filler interception device 45; the second aerobic zone 6 and the degassing zone 7 are separated by a partition wall 23 of the second aerobic zone and the degassing zone; the degassing zone 7 and the sedimentation zone 8 are separated by a partition wall 24 between the degassing zone and the sedimentation zone, and sewage in the second aerobic zone 6 can be introduced into the degassing zone 7 through a water outlet hole 42 of the degassing zone from the second aerobic zone; the sewage from the degassing zone 7 can be introduced into the sedimentation zone 8 through the degassing zone to the sedimentation zone water outlet 43; concentrated sludge obtained by precipitation in the precipitation zone 8 is refluxed to the pre-anoxic zone 1 through a reflux sludge canal 11a, and the reflux sludge canal 11a is provided with a control gate.

The packing ratio of the suspended packing 44 was 35% (the ratio of the volume of the suspended packing to the volume of the reactor); the suspension filler 44 is made of high-density polyethylene, has a particle diameter of 25mm, a wall thickness of 0.4mm, a length of 10mm and a bulk specific gravity of 96+/-2 kg/m ³ Specific surface area>500m ² /m ³ The method comprises the steps of carrying out a first treatment on the surface of the The suspension filler interception device 45 consists of a stainless steel porous interception net, the diameter of round holes of the interception net is 8mm, the center distance of the round holes is 10mm, and a row of coarse bubble diffusers are respectively arranged at the base parts of two sides of the interception net and are 0.9-1.5 m away from the bottom of the reactor; the submerged stirrers in the anaerobic zone and the degassing zone are stirring type; the pre-anoxic zone, the anoxic zone and the aerobic zone are of a push flow type; the aeration systems of the anoxic zone and the aerobic zone consist of disc-type aerators with the diameter D250 and the single maximum ventilation of 4m ³ /h; the aerator comprises a bracket, is made of ABS and is provided with a double-sided buckle.

Reactor structural dimensions (except for the settling zone): l (length) ×b (width) ×h (height) =110×40×7m (effective water depth 6 m), and the longitudinal direction is the right-to-left direction in fig. 3. Wherein, the pre-anoxic zone and the anaerobic zone L (length) ×b (width) ×h (height) = (40×13.5×7m); a first anoxic zone and a first aerobic zone L (length) ×b (width) ×h (height) = (50×40×7m); a second anoxic zone and a second aerobic zone L (length) ×b (width) ×h (height) = (42×40×7m); degassing zone L (length) ×b (width) ×h (height) = (4.5×40×7m). In practice, the reactors of the two groups are operated simultaneously, and a top view of the reactor of group 1 is shown in FIG. 3.

The total treatment amount of the inflow water body is 50000m ³ And/d, the water body is town sewage (medium and high concentration), and the specific water quality information is as follows: COD (chemical oxygen demand) _Cr ：500mg/L；BOD ₅ ：250mg/L；TN：60mg/L；NH ₃ -N：40mg/L；SS：300mg/L；TP：6mg/L。

During treatment, the raw water flow distribution ratio of the pre-anoxic zone is 10%, and the water inflow ratio of the first anoxic zone and the anoxic zone at the front section to the second section is 7:3, the reflux ratio of the sludge in the reaction zone is 50-100% (which can be adjusted as required and can be 100%); the average sludge concentration of the reaction zone is 7000-12000 mg/L (which can be 8170mg/L according to the requirement, and the stirring strength of the pre-anoxic zone is about 5W/m) ³ 4 mixers are configured, and the single power is 1.5kW; anaerobic zone stirring intensity of about 5W/m ³ 4 mixers are configured, and the single power is 3kW; the stirring intensity in the anoxic zone is about 2.5W/m ³ 8 mixers are configured, and the single power is 3kW; aeration intensity of the aerobic zone is 4-6 m ³ /m ² H, 3500 microporous aeration discs are arranged, and aerators are reserved in the first anoxic zone and the second anoxic zone, wherein the aeration capacity is 10-20% of that of the aerobic zone (the aerobic zone is reduced into a conventional A) ² O process state this zone is operated aerobically).

The hydraulic retention time of the pre-anoxic zone is 0.5h, the hydraulic retention time of the anaerobic zone is 1h, the hydraulic retention time of the anoxic zone is 4h, the hydraulic retention time of the aerobic zone is 6.6h, and the hydraulic retention time of the degassing zone is 0.5h; the denitrification load value range of the anoxic zone is 0.03-0.05 kgNO ₃ N/kgMLSS. D (adjusted as required, may be 0.03 kgNO) ₃ -N/kgmlss.d); the sludge load value is 0.05-0.15 kgBOD ₅ /(kgMLSS. D) (adjusted as needed, 0.108 kgBOD) ₅ And/can be (kgMLSS. D)).

The water body obtained by treatment accords with the first-level A standard of pollutant emission standard of urban sewage treatment plant (GB 18918-2002)The operation energy consumption is 0.20-0.22 kW.h/m ³ 。

In summary, the present invention effectively overcomes the disadvantages of the prior art and has high industrial utility value.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims

1. A water treatment method for denitrification and dephosphorization comprises the following steps:

(1) Mixing at least part of water body to be treated with sludge to perform pre-anoxic treatment, wherein the concentration of dissolved oxygen in the water body in the pre-anoxic treatment is less than or equal to 0.5mg/L; in the pre-anoxic treatment, the hydraulic retention time is 0.3-1 h; in the pre-anoxic treatment, the water body is subjected to submerged stirring;

(2) Anaerobic treatment is carried out on the water body obtained by the pre-anoxic treatment, the concentration of dissolved oxygen in the water body in the anaerobic treatment is less than or equal to 0.2mg/L, the water body obtained by the pre-anoxic treatment is subjected to the anaerobic treatment, and at least part of the water body to be treated is introduced for mixing;

in the anaerobic treatment, the hydraulic retention time is 0.5-2 h; in the anaerobic treatment, the water body is subjected to submerged stirring;

in the anoxic treatment, the hydraulic retention time is 0.5-5 h; in the anoxic treatment, the water body is subjected to submerged stirring;

in the aerobic treatment, the hydraulic retention time is 3.5-13 h; in the aerobic treatment, the water body is aerated and stirred;

(4) Carrying out degassing treatment on the water body obtained in the step (3), and adjusting the concentration of dissolved oxygen in the water body to 0.2-0.5 mg/L, wherein in the degassing treatment, the water body is subjected to submerged stirring;

2. A method of water treatment according to claim 1, further comprising one or more of the following features:

(A1) In the pre-anoxic treatment, the sludge load is 0.05-0.15 kg BOD ₅ /(kgMLSS·d)；

(A2) In the pre-anoxic treatment, the concentration of sludge in the water body is 8000-14000 mg/L;

(A3) In the pre-anoxic treatment, the stirring strength of stirring the water body is 4-5W/m ³ ；

(A5) In the pre-anoxic treatment, the concentration of dissolved oxygen in a reaction system is 0.2-0.5 mg/L.

3. A method of water treatment according to claim 1, further comprising one or more of the following features:

(B1) In the anaerobic treatment, the stirring strength of stirring the water body is 4-5W/m ³ The method comprises the steps of carrying out a first treatment on the surface of the (B4) In the anaerobic treatment, supernatant fluid of the water body obtained by the pre-anoxic treatment is subjected to anaerobic treatment.

4. A method of water treatment according to claim 1, further comprising one or more of the following features:

(C1) In the anoxic treatment, the stirring strength of stirring the water body is 1-3W/m ³ ；

(C3) In the anoxic treatment, the denitrification load value of the water body is 0.03-0.06 kgNO ₃ -N/（kgMLSS·d）；

(C4) In the anoxic treatment, the concentration of dissolved oxygen is 0.2-0.5 mg/L.

5. A method of water treatment according to claim 1, further comprising one or more of the following features:

(D1) In the aerobic treatment, the aeration intensity is 4-6 m ³ /m ² ·h；

(D3) In the aerobic treatment, the filler is made of high-density polyethylene;

(D4) In the aerobic treatment, the bulk specific gravity of the filler is 94-98 kg/m ³ ；

(D5) In the aerobic treatment, the specific surface area of the filler>500m ² /m ³ ；

(D6) In the aerobic treatment, the filler is positioned at the rear 4/5 section of the water body according to the advancing direction of the water body;

(D7) In the aerobic treatment, the filler is positioned in a suspended filler zone, and the suspended filler zone is formed by a suspended filler interception device;

(D8) In the aerobic treatment, the filling ratio of the filler is 30-60%.

6. A method of water treatment according to claim 1, further comprising one or more of the following features:

(F1) In the precipitation treatment, more than 50% of the sludge obtained by precipitation is used for pre-anoxic treatment, and the rest sludge is concentrated and dehydrated;

(F2) In the precipitation treatment, the surface load is 0.7-1.8 m ³ /m ² ·h；

(F3) In the precipitation treatment, supernatant obtained by the precipitation treatment meets the main water quality index requirements of GB18918-2002 first-class A standard.

7. A water treatment system for denitrification and dephosphorization, for use in the denitrification and dephosphorization water treatment method according to claim 1, the treatment system comprising a pre-anoxic treatment device (101), an anaerobic treatment device (102), an anoxic and aerobic alternate treatment device (103), a degassing treatment device (106) and a sedimentation treatment device (107) which are in fluid communication in sequence, the anoxic and aerobic alternate treatment device (103) comprising more than one set of anoxic treatment devices (104) and aerobic treatment devices (105) which are in fluid communication in turn, and a water inlet pipe (108), the water inlet pipe (108) being in fluid communication with the pre-anoxic treatment device (104) and/or at least part of the aerobic treatment devices (105), a filler being provided in the aerobic treatment device (105), the sedimentation treatment device (107) being in fluid communication with the pre-anoxic treatment device (101) via a sludge return pipe (110).

8. The water treatment system of claim 7, further comprising one or more of the following features:

(a1) The sludge load in the pre-anoxic treatment device (101) is 0.05-0.15 kg BOD ₅ /(kgMLSS·d)；

(a2) In the pre-anoxic treatment device (101), the concentration of the sludge relative to the water body is 8000-14000 mg/L;

(a3) The pre-anoxic treatment device (101) is provided with a stirring device which is a diving stirring device;

(a4) The pre-anoxic treatment device (101) is in fluid communication with a water intake conduit (108);

(a5) The pre-anoxic treatment device (101) is also provided with a diversion partition wall.

9. The water treatment system of claim 7, further comprising one or more of the following features:

(b1) The anaerobic treatment device (102) is provided with a stirring device, and the stirring device is a submersible stirring device;

(b2) The anaerobic treatment device (102) is in fluid communication with a water intake conduit (108);

(b3) The anaerobic treatment device (102) is in fluid communication with the pre-anoxic treatment device (101) through an overflow device or a water passing hole;

(b4) The anaerobic treatment device (102) is also provided with a diversion partition wall.

10. The water treatment system of claim 7, further comprising one or more of the following features:

(c1) The anoxic treatment device (104) is provided with a stirring device which is a diving stirring device;

(c2) The anoxic treatment device (104) is provided with an aeration device.

11. The water treatment system of claim 7, further comprising one or more of the following features:

(d1) The aerobic treatment device (105) is provided with an aeration device and/or a stirring device;

(d2) In the aerobic treatment device (105), the filler is made of high-density polyethylene;

(d3) In the aerobic treatment device (105), the bulk specific gravity of the filler is 94-98 kg/m ³ ；

(d4) In the aerobic treatment device (105), the specific surface area of the filler>500m ² /m ³ ；

(d5) In the aerobic treatment device (105), the filler is positioned at the rear 4/5 section of the aerobic treatment device according to the advancing direction of the water body;

(d6) In the aerobic treatment device (105), the filler is positioned in a suspended filler zone, and the suspended filler zone is formed by a suspended filler interception device;

(d7) In the aerobic treatment device (105), the filling ratio of the filler is 30-60%;

(d8) The aerobic treatment device (105) is also provided with a diversion partition wall.

12. The water treatment system according to claim 7, wherein the aerobic treatment device (105) is provided with an aeration stirring device.

13. The water treatment system as recited in claim 7, wherein a submersible stirring device is provided in the degasification device (106).

14. The water treatment system of claim 7, further comprising one or more of the following features:

(f1) Further comprising a sludge discharge conduit (111), the sludge discharge conduit (111) being in fluid communication with the sedimentation treatment device (107), further comprising a sludge concentration and dehydration treatment device, the sludge concentration and dehydration treatment device being in fluid communication with the sedimentation treatment device (107) through the sludge discharge conduit (111);

(f2) The sedimentation treatment device comprises a water outlet pipeline (109), and an overflow device is arranged on the water outlet pipeline (109).