CN113896322A

CN113896322A - Device and method for denitrifying and denitrifying rare earth tail water based on MBBR (moving bed biofilm reactor) process

Info

Publication number: CN113896322A
Application number: CN202111207479.2A
Authority: CN
Inventors: 宁小飞; 简陈生; 刘波; 董乔红
Original assignee: Jiangxi Jinjin Environmental Protection Technology Co ltd
Current assignee: Jiangxi Jinjin Environmental Protection Technology Co ltd
Priority date: 2021-10-18
Filing date: 2021-10-18
Publication date: 2022-01-07

Abstract

The invention discloses a device and a method for denitrifying rare earth tail water based on a carrier fluid bed moving bed biofilm reactor process. The reactor used in the device comprises: the device comprises a water inlet facility, a sludge precipitation and backflow facility, a frame type stirrer, a grid net, an MBBR water distribution pipe net, an MBBR reaction box body, a rotary sieve bar, an MBBR filler, a porous slow-release carbon source and the like. The water inlet facility mainly comprises a water inlet tank, a lifting pump and the like, the frame type stirrer is arranged inside the MBBR reaction tank body, and the grid net is arranged on the upper part of the MBBR reaction tank body to play a role in isolating and blocking to prevent the loss of MBBR fillers. The rotating screen bars are arranged on the frame type stirrer and play a role in enhancing stirring. And the rare earth tail water enters the MBBR reaction box through a water inlet facility and is subjected to denitrification and denitrification treatment through a microbial film system grown and propagated in the MBBR filler. The system realizes low-energy-consumption denitrification treatment by optimizing stirring, MBBR filler composition and carbon source addition.

Description

Device and method for denitrifying and denitrifying rare earth tail water based on MBBR (moving bed biofilm reactor) process

Technical Field

The invention relates to the field of sewage treatment, in particular to a device and a method for denitrifying rare earth tail water based on an MBBR (moving bed biofilm reactor) process, which are mainly applied to the field of denitrifying high rare earth tail water.

Background

The rare earth tail water in the drainage basin is waste water with high ammonia nitrogen and nitrate nitrogen contents, which is formed by mother liquor (ammonium sulfate) left in a mine after rare earth is mined by adopting an in-situ mineral leaching process and slowly enters a natural water body along with the surface and underground water, and is the most important source for causing the long-term ammonia nitrogen and total nitrogen exceeding of a surface water system in a mining area. At present, the treatment modes aiming at the ammonia nitrogen in the drainage rare earth tail water mainly comprise high-load underground infiltration technology, a membrane method, a traditional biological denitrification method, synchronous nitrification and denitrification and other processes, but the treatment of total nitrogen is still difficult and serious at present, and the main reason is determined by the characteristics of low concentration of organic matters, poor biodegradability, high salinity and the like in the rare earth tail water. At present, in actual rare earth tail water denitrification operation, the instability of system effluent is caused by factors such as high COD adding cost, difficult process control and the like; CN 106673205A discloses a rapid starting method of an integrated autotrophic nitrogen removal system, which adopts a sequencing batch SBR reactor, inoculates shortcut nitrification sludge and anaerobic ammonia oxidation sludge according to the mass ratio of 1: 3-1: 1, adopts an intermittent aeration operation mode, and can reach the total nitrogen removal load of 0.63kgN/(m3 d) within 30 days under the condition that the total nitrogen removal load of the reactor is 0.3kgN/(m3 d) during the first inoculation; but the method has large inoculation proportion reaching 50-75%, adopts intermittent operation, has large amount in engineering application, and has no large-scale starting significance.

Disclosure of Invention

Aiming at the technical problems in the background technology, (Moving Bed Biofilm Reactor Process), namely a carrier fluidized Bed Moving Bed Biofilm Reactor; the invention provides a rare earth tail water denitrification treatment device and method based on an MBBR (moving bed biofilm reactor) process, and aims to solve the problems that the total nitrogen of the watershed rare earth tail water is difficult to treat and the like.

In order to achieve the purpose, the invention mainly adopts the following technical scheme:

the utility model provides a tombarthite tail water denitrification's device based on MBBR technology, includes into water box, the elevator pump that intakes, the flowmeter of intaking, agitator, grille net, play water weir groove, mud deposit and return-flow system, MBBR water distribution pipe net, MBBR reaction box, rotation grate bar, MBBR filler, components such as porous slowly-releasing carbon source.

Further, the device for the denitrification treatment of the rare earth tail water based on the MBBR process is characterized in that the water inlet tank body, the MBBR reaction tank body and the sludge precipitation reflux system are independent tank bodies or combined tank bodies.

Further, the device sends the rare earth tail water after nitration into the MBBR reaction box through the elevator pump that intakes to through the water distribution network that is located the bottom, in even cloth goes into the reaction box, and utilizes the kinetic energy that the water pump gave the water to stir the mixture to the filler in the MBBR reaction box and activated sludge, prevents that the MBBR filler from piling up in the reaction box bottom.

Furthermore, the upper part of the MBBR reaction box body in the device is provided with a grid mesh strip, and suspended fillers are intercepted inside the reaction box by utilizing the principle that the gap of the grid is smaller than the diameter of the MBBR fillers, so that the loss of the fillers in the system is prevented.

Furthermore, install the rotation screen bars that the quantity is unequal among the paddle of the middle frame agitator of MBBR reaction box in the device, along with the rotation of agitator motor, further cut the stirring to mud, the filler mixed liquid in the MBBR reaction box, strengthen agitator stirring effect.

The invention also provides an operation control method for the denitrification of the rare earth tail water based on the MBBR process, which comprises the steps of introducing the rare earth tail water into a reaction tank filled with the MBBR filler, a porous slow-release carbon source and the activated sludge, promoting the rare earth tail water to flow to the upper part of the reactor through a water distribution pipe network arranged at the bottom of the reactor, mixing the rare earth tail water with a microbial film in the MBBR filler and suspended activated sludge in the reactor, enhancing the stirring through a stirrer, a rotary sieve bar and other facilities arranged on the stirrer, and the like, so as to ensure that the MBBR filler and the activated sludge in the reactor are always in a suspension mixing state, slowly releasing the carbon source into the reactor through the added slow-release carbon source for the denitrification, and supplementing the insufficient carbon source with the inlet water to a certain extent. On the upper part of the reactor, the MBBR filler and the porous slow-release carbon source are firmly isolated and blocked in the reactor through the installed grid net, so that the filler loss is prevented. In the sludge precipitation and reflux system, because certain unconsumed organic matters (COD) and residual sludge still exist in water, denitrification is further carried out in the precipitation system, and the denitrification effect is enhanced; meanwhile, a sludge backflow facility is utilized, a part of sludge-water mixture in the sedimentation tank flows back into the reactor in a large-proportion backflow mode (the ratio of backflow amount to water inflow is 5: 1-10: 1), so that the loss of denitrifying bacteria is further prevented, and the rapid and economical denitrifying denitrification effect is achieved.

Further, the concentration of dissolved oxygen in the MBBR reactor is controlled to be 0.3-0.8 mg/L. If the dissolved oxygen is higher than 0.8mg/L, the stirring speed of the reactor needs to be reduced, and a sealing cover can be arranged at the upper part of the reactor to prevent oxygen in the air from entering.

Further, the sludge concentration (MLSS) in the reaction zone is controlled to be 5000-8000 mg/L, and the sludge age (SRT) of the sludge is controlled to be 30-35 days.

If the sludge concentration in the mixed reaction zone is lower than 5000mg/L, the method is debugged by adopting one or more of the following modes: firstly, manually adding a proper amount of activated sludge subjected to denitrification domestication; secondly, the sludge reflux proportion is increased in a proper amount; and thirdly, properly increasing the concentration of the organic matters in the inlet water. If the sludge in the mixed reaction zone is higher than 8000mg/L, a manual sludge discharge mode is adopted to properly discharge the sludge.

Further, in order to avoid the impact of the inlet water on the system stability, preferably, the pH value of the inlet water is controlled to be 7.5-8.0, and the carbon-nitrogen ratio (C/N) of the inlet water is controlled to be 2.5: 1-5: 1.

Preferably, the ratio of the added volume of the MBBR filler in the reactor to the volume of the reactor is controlled to be 0.5-0.8, the MBBR filler preferably uses a polyurethane sponge biological filler and a porous rotary spherical suspension filler, and the two fillers can be mixed for use.

The invention has the following benefits:

1) this application adopts a tombarthite tail water denitrification's device based on MBBR technology, and the suspension form MBBR filler that is big through the porosity of throwing, specific surface area provides the carrier of nidation for the microorganism to improve the interior microbial biomass of system and richen the biological species.

2) In the tombarthite tail water denitrification's based on MBBR technology device, the MBBR of suspension form packs to adsorb and adheres to a large amount of microorganism and forms the biomembrane, because biomembrane thickness constantly increases, the inside depths that oxygen can not the impenetrated will change into anaerobic state, thereby reach all simultaneously containing different biological species in each packs, pack the most inside anaerobism fungus, outwards be facultative aerobe and aerobic bacteria respectively in proper order, every filler unit all can become a miniature possesses the nitration like this, denitrification in the reactor of an organic whole, thereby treatment effect has been improved.

3) In the device for the denitrification treatment of the rare earth tail water of the MBBR process, the suspended MBBR filler is added into the MBBR, the biofilm on the surface of the suspended MBBR filler can grow a large number of various microorganisms under aerobic conditions, and the biomass of the suspended MBBR filler and the biomass of the activated sludge in the tank grow together in one tank, so that the biomass in unit volume is obviously improved, the nitrification load is obviously improved, and the concentration of the ammonia nitrogen in the effluent can be reduced to a very low level.

4) According to the invention, the water outlet weir groove is arranged along the whole width of the water inlet cross section of the side of the MBBR reaction box body, so that the flow velocity of the mixed liquid on the cross section of the MBBR reaction box body can be greatly reduced, the suspended carriers in the MBBR reaction box body are uniformly distributed, and the suspended carriers are prevented from being blocked on the MBBR interception grid net due to overlarge flow velocity of the mixed liquid.

5) The MBBR internal sludge reflux pump is arranged at the bottom of the MBBR reaction box body, so that a porous slow-release carbon source and an MBBR filler are effectively prevented from entering an internal reflux pump area; the porous slow-release carbon source and the MBBR filler are uniformly arranged in the MBBR reaction box body by rotating the sieve bars, so that the suspended carrier can be effectively prevented from being blocked on the water outlet screen.

6) The sewage treatment biochemical pool which needs to be upgraded and modified does not need to be newly increased in construction land; for a new construction, the invention can greatly save the occupied area of the biological pond; the invention is suitable for new construction or upgrading reconstruction of sewage treatment facilities of various scales, and can also be applied to an integrated sewage device occupying less land.

Drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings of the apparatus are briefly described below, and for those skilled in the art, other drawings can be obtained without inventive effort.

FIG. 1 is a schematic view of the structure of the present invention.

In the figure: 1-a water inlet tank body; 2-a water inlet lift pump; 3-a water inlet flowmeter; 4-a stirrer; 5-a grid net; 6-water outlet weir notch; 7-a sludge sedimentation tank; 8-a sludge reflux pump; 9-MBBR water distribution pipe network; 10-porous slow-release carbon source; 11-MBBR reaction box body; 12-rotating the screen bars; 13-MBBR filler.

Detailed Description

The invention will now be described in further detail with reference to the accompanying drawings and examples, which are simplified schematic drawings and illustrate only the basic structure of the invention in a schematic manner, and thus show only the constituents relevant to the invention.

The invention preferably provides a set of rare earth tail water denitrification device based on an MBBR (moving bed biofilm reactor) process as shown in the attached drawing, which mainly comprises a water inlet system, an MBBR reaction system, a sludge precipitation reflux system and accessory structures thereof; the water inlet system comprises a water inlet tank 1, a water inlet pump 2, a flow meter 3, a water distribution pipe network 9 and the like; the MBBR reaction system comprises a reaction box body 11, MBBR fillers 13, a porous slow-release carbon source 10, a stirrer 4, a grid net 5, a rotary screen 12 for auxiliary stirring and the like.

Among the above-mentioned device, the preferential integral type combination box structure of chooseing of water inlet system, MBBR reaction system and mud sedimentation return-flow system, but the rational utilization space is so that the area of using land is practiced thrift. The water outlet weir notch 6 and the grid mesh 5 in the MBBR reaction system are connected together in a hinge or bolt mode, the grid mesh can be freely installed and detached, the water outlet of the water outlet weir notch 6 is connected with the sedimentation tank 7 in a pipeline or water hole passing mode, and if a vertical sedimentation tank is adopted, the flow velocity in the central guide cylinder of the sedimentation tank needs to be ensured not to be more than 0.3 m/s. The stirrer 4 is fixed to the top of the reactor in a channel steel welding mode, the rotating screen 12 for auxiliary stirring is fixed to a stirrer blade in a buckling or spot welding mode, and the installation gap is 5-10 cm. The bottom of the sedimentation tank 7 is connected with a sludge reflux pump 8 through a reserved reflux pipeline, and part of sludge in the sedimentation tank 7 is refluxed into an MBBR reaction box 11.

In the actual application process, the rare earth tail water in the water inlet tank sends the nitrogen-containing wastewater into the MBBR reaction system through the lift pump, and the water inlet amount is regulated and controlled by the flow meter. After the wastewater enters the MBBR, the wastewater uniformly contacts with the suspended MBBR filler, suspended free activated sludge and a porous slow-release carbon source through a Chinese character feng-shaped pipe network arranged at the bottom of the reactor, nitrogen-containing pollutants and organic matters in the wastewater are adsorbed by a microbial film attached to the surface of the MBBR filler in the contact process of the MBBR filler and are transferred to the inside of the microbial film, in the transfer process, a small part of the organic matters and the nitrogen-containing pollutants are used for maintaining the normal metabolism of the microorganisms, and a large part of the organic matters and the nitrogen-containing pollutants are reduced into nitrogen by denitrifying bacteria and are discharged into the atmosphere.

In order to ensure the quick start of the system:

preferably, activated sludge subjected to denitrification domestication is preferentially inoculated, and if not, secondary sedimentation tank excess sludge of a municipal sewage treatment plant can be selected nearby as an inoculation sludge source.

Preferably, the ratio of the volume of the suspended filler filled by the MBBR to the volume of the reactor is controlled to be 0.5-0.8;

preferably, the ratio of the filling volume of the porous slow-release carbon source to the volume of the reactor is 0.3-0.5;

preferably ensuring that the concentration of sludge in the tank is not less than 4000mg/L, keeping all equipment of the system to continuously operate for 24 hours, strictly controlling the rotating speed of the stirrer 4 within 10 revolutions per minute, and ensuring that the amount of backflow of the sludge backflow pump 8 is at least 5-10 times of the amount of inflow water;

meanwhile, the numerical value of total nitrogen of inlet water is gradually increased by adopting a mode of increasing the pollution concentration of inlet water in stages, and outlet water is taken at least 2 times per day for water quality analysis until the system stably operates.

The present invention will be described in detail with reference to specific examples.

Example 1:

the daily treated water amount of a pilot test project for treating the rare earth tail water in a certain rare earth drainage basin in Longnan is 7.2m³And d, the concentration of nitrate nitrogen in the inlet water is 80-150 mg/L, the concentration of total nitrogen in the inlet water is 90-170 mg/L, the concentration of COD in the inlet water is 0-40 mg/L, and the concentration of total phosphorus is 0.1-0.5 mg/L. The rare earth tail water denitrification device based on the MBBR technology is adopted for testing. In the experiment, a mode of manually adding a carbon source is adopted for supplementing a denitrification carbon source, the carbon source respectively adopts sodium acetate, glycerol/propylene glycol/sodium acetate mixed carbon source and glucose, an all-weather water inlet mode is adopted, the ratio of the filling volume of the MBBR suspended filler to the volume of the reactor is 0.6, the concentration of suspended sludge in the reactor is 5500mg/L, and the reflux ratio is controlled to be 5: 1-10: 1. The test results are shown in the table below.

The results in table 1 show that the effect of the rare earth tail water denitrification treatment based on the MBBR process can meet the corresponding emission requirements in the national emission standard of rare earth industrial pollutants, and meanwhile, the comparison test on the ratio of the COD concentration of the inlet water to the total nitrogen concentration of the inlet water shows that the average value is 3.11, the minimum value is 1.35, and the ratio of the COD concentration of the inlet water to the total nitrogen concentration of the inlet water in the traditional denitrification process is more than 5.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A device for denitrifying and denitrifying rare earth tail water based on an MBBR (moving bed biofilm reactor) process mainly comprises a water inlet system, an MBBR reaction system, a sludge precipitation reflux system and accessory structures thereof; the method is characterized in that: the water inlet system comprises a water inlet tank, a water inlet pump, a flow meter and a water distribution pipe network; the MBBR reaction system comprises a reaction box body, MBBR fillers, a porous slow-release carbon source, a stirrer, a grid net and a rotary sieve for auxiliary stirring; the denitrification device reduces the nitrate nitrogen in the rare earth tail water into nitrogen through a biological membrane system attached to the surfaces of the MBBR filler and the porous slow-release carbon source and the inner part of the MBBR filler and the porous slow-release carbon source.

2. The device for denitrifying rare earth tail water based on the MBBR process according to claim 1, characterized in that: the MBBR water inlet system adopts a Chinese character feng-shaped water distribution system, the pipe diameter of a water distribution pipe network is phi 50 mm-phi 110mm, the hole diameter phi 4 mm-phi 10mm of the water distribution pipe network is opened, the hole opening direction is 45 degrees, holes are upwards staggered and opened, and the hole distance is not more than 25 cm.

3. The device for denitrifying rare earth tail water based on the MBBR process according to claim 1, characterized in that: the aperture of the grid mesh is not more than phi 20mm, and the material of the grid mesh comprises but is not limited to stainless steel and PP reinforced plastics.

4. The device for denitrifying rare earth tail water based on the MBBR process according to claim 1, characterized in that: the stirrer in the MBBR is a frame stirrer or a paddle stirrer, and the installation distance of the rotating screen is 5-10 cm.

5. The device for denitrifying rare earth tail water based on the MBBR process according to claim 1, wherein: the sludge settling system in the sludge settling and refluxing system is a vertical flow settling tank or a radial flow settling tank.

6. The device for denitrifying rare earth tail water based on the MBBR process according to claim 1, wherein: the porous slow-release carbon source is mainly prepared by sintering a mixture of straws, ceramsite soil and animal manure at high temperature and high pressure.

7. A denitrification method adopting the MBBR process-based rare earth tail water denitrification device is characterized in that: introducing rare earth tail water into a reaction tank body filled with MBBR (moving bed biofilm reactor) fillers, porous slow-release carbon sources and activated sludge, promoting the MBBR fillers and the activated sludge in the reactor to be always in a suspension mixing state through a water distribution pipe network and a frame type stirrer which are arranged at the bottom of the reactor, slowly releasing the carbon sources into the reactor through the added slow-release carbon sources for denitrification, and supplementing the insufficient carbon sources with inlet water to a certain extent; the MBBR filler is isolated and blocked from the reactor through a grid net arranged on the upper part of the reactor, so that the filler is prevented from losing; meanwhile, a sludge backflow facility is utilized to backflow a part of sludge-water mixture in the sedimentation tank into the reactor, so as to further prevent the loss of denitrifying bacteria, thereby achieving the rapid and economic denitrifying denitrification effect.

8. The method for denitrifying rare earth tail water based on the MBBR process according to claim 7, which is characterized in that: the stirrer works at a rotating speed not exceeding 10 revolutions per minute (r/min), the concentration of Dissolved Oxygen (DO) in the reaction box body is controlled to be 0.3-0.8 mg/L, and the concentration of sludge (MLSS) in the reaction box body is controlled to be 5000-8000 mg/L.

9. The method for denitrifying rare earth tail water based on the MBBR process according to claim 7, which is characterized in that: the ratio of the volume of the MBBR filler in the reactor to the volume of the reactor is controlled to be 0.5-0.8.

10. The method for simultaneous nitrification and denitrification of nitrogen in wastewater according to claim 7, wherein: the carbon-nitrogen ratio (C/N) of the inlet water is controlled to be 2.5: 1-5: 1, and the reflux ratio is controlled to be 5: 1-10: 1; the carbon source added in the inlet water is one or more of glucose, sodium acetate, ethanol, glycerol and various low molecular alcohols.