CN108558128B - Co-flocculation air-float anaerobic bioreactor and method thereof - Google Patents

Abstract

The invention discloses a co-flocculation air flotation anaerobic bioreactor and a method thereof. The co-flocculation air flotation anaerobic bioreactor mainly includes a biological reaction zone, a dosing mixing zone and a flocculation air flotation zone. The biological reaction zone is equipped with a mud discharge pipe, a three-phase separator and a riser. The dosing mixing zone is equipped with a solvent Medicine tank, flow control valve and ejector, the flocculation air flotation area is equipped with a DC vortex reaction tank, downflow chamber, slag scraper, slag collecting tank, downflow pipe and gas collecting chamber. The invention combines the anaerobic biological reaction and the co-flocculation air flotation process, uses the biogas generated by the anaerobic biological reaction to remove particulate matter by air flotation, and at the same time produces a copolymerization adhesion effect, so that the effluent quality is good, chemicals are saved, and efficiency is High and low energy consumption characteristics.

Description

Co-flocculation air flotation anaerobic bioreactor and method thereof

Technical field

The invention belongs to the field of environmental protection equipment, and specifically relates to a co-flocculation air flotation anaerobic bioreactor and a method thereof.

Background technique

Anaerobic bioreactor is a device that uses anaerobic microorganisms to convert organic matter in wastewater into biogas to achieve water purification. The main advantages of anaerobic bioreactors are: no need for oxygen supply, biogas energy generation, less residual sludge, and low nutritional requirements. Therefore, anaerobic bioreactors are widely used in the field of treating high-concentration organic wastewater. After years of development, anaerobic bioreactors have various configurations and have experienced three stages of development. The first generation of anaerobic bioreactors are mainly represented by traditional anaerobic digesters; the second generation of anaerobic bioreactors are mainly represented by traditional anaerobic digesters. Represented by upflow sludge bed reactor (UASB) and anaerobic biological filter (AF); the third generation anaerobic bioreactor mainly includes anaerobic granular sludge expanded bed reactor (EGSB) and internal circulation reactor (IC) is the representative. By the third generation of anaerobic bioreactors, the organic volume load can reach more than 20kg COD·m ^-3 ·d ^-1 , and achieve better removal rates.

High-concentration complex wastewater (such as livestock and poultry breeding wastewater, slaughtering wastewater, papermaking wastewater, etc.) contains a large number of particulate organic pollutants. Its complete removal requires a hydrolysis-fermentation-methane production process, and the hydrolysis of particulate matter is the limit of the entire process. Quick steps. Therefore, when treating high-concentration complex wastewater, in order to ensure a certain pollutant removal rate, anaerobic bioreactors can often only operate at low loads, and their treatment potential is completely suppressed. For anaerobic bioreactors to efficiently treat high-concentration complex wastewater, they must first efficiently remove particulate matter. Air flotation devices are usually installed in wastewater treatment projects to remove particulate matter, but this will increase the complexity of the project and increase infrastructure investment. For the low-profit farming industry, wastewater treatment must ensure that the effluent meets discharge standards at a low cost, so the development of anaerobic bioreactors with air flotation functions is of great practical significance.

The adhesion between particulate matter and bubbles is the key to the air flotation process. If coagulant is added and the colloid is in the primary reaction stage of destabilizing and coagulating, the tiny biogas bubbles will first adhere to the microflocs and then grow together during the flotation process. Large, they adhere and aggregate with other particles or microflocs to form air-laden flocs, forming a copolymerization and adhesion phenomenon that includes interparticle entrapment and intermediate bubble bridging. The invention combines anaerobic biological reaction and copolymerization adhesion, and is advanced and practical.

Contents of the invention

The purpose of the present invention is to solve the problems existing in the prior art and provide a co-flocculation air flotation anaerobic bioreactor.

A co-flocculation air flotation anaerobic bioreactor includes a water inlet area, a biological reaction area, an outlet area, a dosing mixing area and a flocculation air flotation area arranged from bottom to top; the water inlet area is provided with an inlet pipe and an inlet pipe. One end of the water pipe is connected to the water distributor, and the bottom of the water inlet area is connected to the mud discharge pipe; the upper part of the biological reaction area is equipped with a three-phase separator, and the three-phase separator is connected to the riser; the water outlet area is equipped with an outlet weir; the dosing mixing area is equipped with Dissolving tank, flow control valve and ejector. The dissolving tank is connected to the throat of the ejector through a pipeline with a flow control valve. The inlet of the ejector is connected to the riser pipe; a DC vortex is installed in the flocculation air flotation zone. Reaction tank and downflow chamber. The DC vortex reaction tank is a continuous two-stage structure. The lower section is in the shape of an inverted cone and the upper section is in the shape of a straight cylinder. The DC vortex reaction tank is coaxially located along the center of the flocculation and air flotation zone. , the downflow chamber is sandwiched between the outer wall of the DC vortex reaction tank and the inner wall of the flocculation air flotation zone. The bottom of the DC vortex reaction tank is connected to the outlet of the ejector. There is a downflow pipe at the bottom of the downflow chamber. The downflow pipe Connected to the water distributor; there is a slag scraper at the liquid level of the downflow chamber, and a slag collecting tank is arranged around the outside of the downflow chamber to collect the scum scraped out by the slag scraper; there are A closed space forms a gas collecting chamber for collecting the gas produced by the reactor, and an exhaust pipe is provided on the gas collecting chamber.

Based on the above solution, each component can also adopt the following preferred methods:

The volume ratio of the biological reaction zone to the flocculation air flotation zone is 50 to 100:1. The height-to-diameter ratio of the biological reaction zone is 5 to 10. The ratio of the cross-sectional area of the biological reaction zone to the cross-sectional area of the riser is greater than 2500:1, and the diameter of the riser is not greater than 50mm. The volume ratio of the once-through vortex reaction tank and the downflow chamber in the flocculation air flotation zone is 1:2. The bottom inlet of the once-through vortex reaction tank in the flocculation air flotation zone is equipped with a guide vane structure. The bottom cone angle of the once-through vortex reaction tank in the flocculation and air flotation zone is 30° to 45°, and the ratio of the height of the inverted conical cylinder to the height of the straight cylinder of the once-through vortex reaction tank is 1 to 2:1. The biological reaction zone is filled with a bed of granular sludge.

A method for anaerobic biological treatment of wastewater using the co-flocculation air flotation of the above reactor, specifically: the wastewater enters the water distributor through the water inlet pipe, and the water distributor evenly distributes the wastewater in the water inlet section of the reactor, allowing the wastewater to enter Biological reaction zone; in the biological reaction zone, wastewater flows through the granular sludge bed, dissolved organic matter is converted into biogas through the action of microorganisms, and particulate matter moves upward from the pores of the granular sludge bed. In the three phases of the biological reaction zone Three-phase separation is performed at the separator. The separated reaction liquid part enters the outlet weir in the water outlet area from the biological reaction area and is discharged from the reactor. The mixed liquid composed of biogas, reaction liquid and unseparated solids is collected from the three-phase separator. The mixed liquid enters the riser tube, and then enters the dosing mixing zone through the riser tube; in the dosing mixing zone, the mixed liquid enters the ejector and is ejected from the nozzle into the throat, and the pressure drop is used in the mixing chamber at the front end of the throat to inhale the dissolved medicine The flocculant solution in the tank, the mixed liquid after adding the medicine enters the flocculation air flotation zone through the throat; in the flocculation air flotation zone, the mixed liquid enters the DC vortex reaction tank through the inlet of the guide vane structure, and flows in the inverted conical cylinder part Mixing is carried out to achieve the primary reaction, and then it enters the straight part. As the diameter expands, the water flow gradually eases to achieve floc growth; the floc with bubbles floats to the liquid surface to form scum, which is removed by the slag scraper and collected in the slag collecting tank. , the biogas escaping from the liquid surface enters the gas collecting chamber, and the degassed reaction liquid returns from the downflow chamber to the water distributor through the downflow pipe, forming an internal circulation of the mixed liquid; the sludge in the reactor is regularly discharged from the sludge tube discharge. The dosage of flocculant can be adjusted through the flow control valve.

The advantages of this invention are: 1) flocculation and air flotation are carried out simultaneously in the flocculation and air flotation zone, producing a copolymerization and adhesion effect, saving chemicals, short processing time and good scum stability; 2) The large aspect ratio of the biological reaction zone is conducive to increasing the The flow rate rises so that particulate matter does not settle in the biological reaction zone but enters the flocculation and flotation zone with the mixed liquid, which strengthens the removal of particulate matter; 3) Use an ejector as a dosing device in the dosing mixing zone to cooperate with flow control valve, which can save power and ensure sufficient mixing; 4) The DC vortex reaction tank in the flocculation air flotation zone has the characteristics of small pressure drop, and there is no need to increase the pressure of the mixed liquid; 5) The DC vortex reaction tank in the flocculation air flotation zone The vigorous mixing of the water flow in the conical cylinder part of the pool corresponds to the fast stirring process in the flocculation experiment; the gentle water flow in the straight cylinder part corresponds to the slow mixing process in the flocculation experiment. The floc floats to the liquid surface and is immediately removed by the slag scraper. The scum generation process is stable and Quick removal; 6) Particulate matter in wastewater forms scum with high energy density, which can be used for composting to recover energy, and the effluent has less particulate matter and good effluent quality.

Description of the drawings

Figure 1 is a schematic diagram of the functional area of the co-flocculation air flotation anaerobic bioreactor;

Figure 2 is a schematic structural diagram of a co-flocculation air flotation anaerobic bioreactor;

In Figure 1: water inlet area I, biological reaction area II, water outlet area III, dosing mixing area IV and flocculation air flotation area V;

In Figure 2: water inlet pipe 1, water distributor 2, mud discharge pipe 3, three-phase separator 4, riser pipe 5, water outlet weir 6, solvent tank 7, flow control valve 8, ejector 9, DC vortex Reaction tank 10, downflow chamber 11, slag scraper 12, slag collecting tank 13, downflow pipe 14, and gas collection chamber 15.

Detailed ways

The present invention will be further elaborated and described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 1 and 2, a co-flocculation air flotation anaerobic bioreactor includes a water inlet zone I, a biological reaction zone II, a dosing mixing zone IV and a flocculation air flotation zone connected in sequence from bottom to top. V, water outlet area III is arranged above the biological reaction area II. The water inlet area I, the biological reaction area II, and the outlet area III are connected in sequence to form a cylindrical reactor body. The bottom of the water inlet area I is funnel-shaped. The water inlet area I is provided with a water inlet pipe 1 and a water distributor 2 connected to one end of the water inlet pipe 1. The bottom of the water inlet area I is connected to a mud discharge pipe 3, and a control valve can be installed on the mud discharge pipe 3. The biological reaction zone II is filled with a bed of granular sludge. A three-phase separator 4 is provided at the upper part of the biological reaction zone II, and the gas phase collector outlet of the three-phase separator 4 is connected to a riser 5. The liquid phase channel of the three-phase separator 4 is connected to the water outlet area III, and an outlet weir 6 is provided in the water outlet area III. The dosing mixing zone IV is equipped with a chemical dissolving tank 7, a flow control valve 8 and an ejector 9. The ejector 9 has a mixing chamber. The inlet of the ejector 9 extends into the mixing chamber, and the end of the pipe at the inlet is in the shape of a nozzle. The mixing chamber is also connected to a throat. When the water flow is sprayed into the mixing chamber, it continues to enter the throat, generating negative pressure based on the Venturi effect. The chemical solution tank 7 is used to store the flocculant solution and is connected to the mixing chamber at the front end of the throat of the ejector 9 through a pipeline with a flow control valve 8 . The inlet of the ejector 9 is connected with the riser pipe 5 . The flocculation air flotation zone V is provided with a DC vortex reaction tank 10 and a downflow chamber 11. The DC vortex reaction tank 10 is a continuous two-section structure, with the lower section being in the shape of an inverted conical cylinder and the upper section being in the shape of a straight cylinder. When the water flow enters the lower section, turbulence will occur due to the continuous increase in diameter, resulting in violent mixing. After entering the upper section, the water flow tends to be stable, and the flocs gradually agglomerate and grow during the collision and contact process. The DC vortex reaction tank 10 is coaxially arranged along the center of the flocculation air flotation zone V. The downflow chamber 11 is sandwiched between the outer wall of the DC vortex reaction tank 10 and the inner wall of the flocculation air flotation zone V, and is arranged in a ring shape in the DC Outside the vortex reaction tank 10, the overflowing water flow in the direct-flow vortex reaction tank 10 will enter the downflow chamber 11, and the floc will be carried by the bubbles and rise to the liquid surface. The bottom of the DC vortex reaction tank 10 is connected to the outlet of the ejector 9, and a downflow pipe 14 is provided at the bottom of the downflow chamber 11. The downflow pipe 14 is connected to the water distributor 2 to form a circulation loop. A slag scraper 12 is provided at the liquid surface of the downflow chamber 11, and a slag collecting tank 13 is provided around the outside of the downflow chamber 11 for collecting scum scraped out by the slag scraper 12; the downflow chamber 11 and the slag collecting tank 13 There is a closed space at the top to form a gas collecting chamber 15 for collecting the gas produced by the reactor. The gas collecting chamber 15 is provided with an exhaust pipe.

The parameters of each component in the reactor can be set as follows: the volume ratio of the biological reaction zone II to the flocculation air flotation zone V is 50 to 100:1. The height-to-diameter ratio (H/D) of biological reaction zone II is 5 to 10. The ratio of the cross-sectional area of the biological reaction zone II to the cross-sectional area of the riser tube 5 is greater than 2500:1, and the diameter of the riser tube 5 is not greater than 50mm. The volume ratio of the straight-flow vortex reaction tank 10 and the downflow chamber 11 in the flocculation air flotation zone V is 1:2. The bottom inlet of the DC vortex reaction tank 10 in the flocculation air flotation zone V is provided with a guide vane structure. The bottom cone angle of the DC vortex reaction tank 10 in the flocculation and air flotation zone V is 30° to 45°, and the ratio of the height of the inverted conical cylinder to the height of the straight cylinder of the DC vortex reaction tank 10 is 1 to 2:1.

The method of co-flocculation air flotation anaerobic biological treatment of wastewater based on the above reactor has the following steps: wastewater enters the water distributor 2 through the water inlet pipe 1, and the water distributor 2 evenly distributes the wastewater in the water inlet area I section of the reactor, The wastewater enters the biological reaction zone II; in the biological reaction zone II, the wastewater flows through the granular sludge bed, and the dissolved organic matter is converted into biogas through the action of microorganisms, and the granular materials move upward from the pores of the granular sludge bed. Three-phase separation is performed at the three-phase separator 4 in the reaction zone II. The separated reaction liquid part enters the outlet weir 6 in the outlet zone III from the biological reaction zone II and is discharged from the reactor. The biogas, reaction liquid and unseparated solids are composed of The mixed liquid enters the riser 5 from the collector of the three-phase separator 4, and then enters the dosing mixing zone IV through the riser 5; in the dosing mixing zone IV, the mixed liquid enters the ejector 9 and is ejected from the nozzle into the throat. , in the mixing chamber at the front end of the throat, the pressure drop is used to inhale and dissolve the flocculant solution in the medicine tank 7. The dosage of the flocculant is adjusted through the flow control valve 8; the mixed liquid after adding the medicine enters the flocculation and flotation zone through the throat. Ⅴ; In the flocculation air flotation zone Ⅴ, the mixed liquid enters the DC vortex reaction tank 10 through the inlet of the guide vane structure. In the inverted conical cylinder part, the water flow is violently mixed to achieve the primary reaction, and then enters the straight cylinder part. As the diameter expands, the water flow gradually Ease and achieve floc growth; the flocs wrapped with bubbles float to the liquid surface to form scum, which is removed by the slag scraper 12 and collected in the slag collecting tank 13. The biogas escaping from the liquid surface enters the gas collection chamber 15 and is desorbed. The degassed reaction liquid returns from the downflow chamber 11 to the water distributor 2 via the downflow pipe 14, forming an internal circulation of the mixed liquid; the sludge in the reactor is regularly discharged from the sludge discharge pipe 3.

The key to realizing the co-flocculation air flotation process of the present invention lies in the height ratio of the conical cylinder part and the straight cylinder part in the DC vortex reaction tank in the flocculation air flotation zone. By controlling the height ratio of the tapered cylinder part and the straight cylinder part in the DC vortex reaction tank to enhance the copolymer adhesion effect. The reactor must operate under high load, so increase the cross-sectional area of the biological reaction zone or reduce the cross-sectional area of the riser to obtain liquid lifting power.

Claims (8)

1. A co-flocculation air flotation anaerobic bioreactor, characterized by: including an inlet area (I), a biological reaction area (II), an outlet area (III), and a dosing mixing area (IV) arranged from bottom to top. ) and the flocculation air flotation area (V); the water inlet area (I) is provided with a water inlet pipe (1) and a water distributor (2) connected to one end of the water inlet pipe (1). The bottom of the water inlet area (I) is connected to a drain Mud pipe (3); a three-phase separator (4) is provided at the upper part of the biological reaction zone (II), and a riser pipe (5) is connected to the three-phase separator (4); an outlet weir (6) is provided in the water outlet area (III) ; The dosing mixing area (IV) is equipped with a chemical dissolving tank (7), a flow control valve (8) and an ejector (9). The chemical dissolving tank (7) passes through a pipeline with a flow control valve (8) and the ejector The throat of (9) is connected, and the inlet of the ejector (9) is connected with the riser (5); the flocculation air flotation zone (V) is equipped with a DC vortex reaction tank (10) and a downflow chamber (11). The DC vortex reaction tank (10) is a continuous two-stage structure. The lower section is in the shape of an inverted conical cylinder and the upper section is in the shape of a straight cylinder. The DC vortex reaction tank (10) is in the same direction along the center of the flocculation air flotation zone (V). The downflow chamber (11) is sandwiched between the outer wall of the DC vortex reaction tank (10) and the inner wall of the flocculation air flotation zone (V). The bottom of the DC vortex reaction tank (10) is connected to the ejector (9) ), a downflow pipe (14) is provided at the bottom of the downflow chamber (11), and the downflow pipe (14) is connected to the water distributor (2); a slag scraper (12) is provided at the liquid surface of the downflow chamber (11) ), the downflow chamber (11) is surrounded by a slag collecting tank (13) for collecting scum scraped out by the slag scraper (12); the tops of the downflow chamber (11) and the slag collecting tank (13) have A closed space forms a gas collecting chamber (15) for collecting the gas produced by the reactor, and the gas collecting chamber (15) is provided with an exhaust pipe; The volume ratio of the biological reaction zone (II) to the flocculation and flotation zone (V) is 50~100:1; the height-to-diameter ratio of the biological reaction zone (II) is 5~10. 2. A co-flocculation air flotation anaerobic bioreactor according to claim 1, characterized in that the ratio of the cross-sectional area of the biological reaction zone (II) to the cross-sectional area of the riser (5) is greater than 2500:1, and The diameter of the riser tube (5) shall not be greater than 50 mm. 3. A co-flocculation air flotation anaerobic bioreactor according to claim 1, characterized in that the volumes of the once-through vortex reaction tank (10) and the downflow chamber (11) in the flocculation air flotation zone (V) The ratio is 1:2. 4. A co-flocculation air flotation anaerobic bioreactor according to claim 1, characterized in that the bottom inlet of the once-through vortex reaction tank (10) in the flocculation air flotation zone (V) is provided with a guide vane structure. 5. A co-flocculation air flotation anaerobic bioreactor according to claim 1, characterized in that the bottom cone angle of the once-through vortex reaction tank (10) in the flocculation air flotation zone (V) is 30°~45 °, the ratio of the height of the inverted conical cylinder and the height of the straight cylinder of the DC vortex reaction cell (10) is 1~2:1. 6. A co-flocculation air flotation anaerobic bioreactor according to claim 1, characterized in that the biological reaction zone (II) is filled with a bed of granular sludge. 7. A method for anaerobic biological treatment of wastewater using co-flocculation air flotation in the reactor of claim 1, characterized in that the wastewater enters the water distributor (2) through the water inlet pipe (1), and the water distributor (2) The wastewater is evenly distributed in the cross-section of the inlet area (I) of the reactor, so that the wastewater enters the biological reaction area (II); in the biological reaction area (II), the wastewater flows through the granular sludge bed, and the dissolved organic matter undergoes microbial action Converted into biogas, the particulate matter moves upward from the pores of the granular sludge bed, and performs three-phase separation at the three-phase separator (4) of the biological reaction zone (II). The separated reaction liquid part is discharged from the biological reaction zone (II). Ⅱ) Enters the outlet weir (6) in the outlet area (Ⅲ) and discharges from the reactor. The mixed liquid composed of biogas, reaction liquid and unseparated solids enters the riser (5) from the collector of the three-phase separator (4). , and then enters the dosing mixing zone (IV) through the riser (5); in the dosing mixing zone (IV), the mixed liquid enters the ejector (9) and is ejected from the nozzle into the throat. In the mixing chamber at the front end of the throat The pressure drop is used to suck and dissolve the flocculant solution in the medicine tank (7). The mixed liquid after adding the medicine enters the flocculation air flotation zone (V) through the throat; in the flocculation air flotation zone (V), the mixed liquid passes through the guide vane The entrance of the structure enters the once-through vortex reaction tank (10), and the water flow is mixed in the inverted cone-shaped cylinder part to achieve the primary reaction, and then enters the straight cylinder part. As the diameter expands, the water flow gradually relaxes to achieve floc growth; the flocs with bubbles are wrapped The body floats to the liquid surface to form scum, which is removed by the slag scraper (12) and collected in the slag collecting tank (13). The biogas escaping from the liquid surface enters the gas collecting chamber (15), and the degassed reaction liquid falls from the The flow chamber (11) returns to the water distributor (2) through the downflow pipe (14), forming an internal circulation of the mixed liquid; the sludge in the reactor is regularly discharged from the sludge discharge pipe (3). 8. The method according to claim 7, characterized in that the dosage of flocculant is adjusted through the flow control valve (8).