CN101269877A - Two-stage anaerobic digestion cycle stripping system - Google Patents

Abstract

The invention discloses a two-stage anaerobic digestion cycle blow-off system, which is an anaerobic sewage treatment device suitable for high-concentration sulfate and organic pollutants. The system consists of water inlet pipe, water inlet pump, swirling anaerobic fluidized bed, fluidized bed outlet pipe, composite reactor, return pipe, circulation pump, and reactor outlet pipe. The swirling anaerobic fluidized bed includes Fluidized bed tank, mixer, substrate adsorption tube, swirl water distributor, upflow chamber, swirl baffle, fluidized bed gas collection hood, fluidized bed outlet tank, composite reactor including reactor tank , blow-off chamber, microporous diffuser, air inlet pipe, sludge sedimentation area, suspended active packing layer, reactor gas collection hood, and reactor outlet tank. This system overcomes the difficulty of traditional anaerobic treatment of organic sulfate wastewater, and has the advantages of high volume load, high organic matter removal efficiency, good desulfurization effect, strong impact load resistance, stable operation, and low cost.

Description

Two-stage anaerobic digestion cycle stripping system

1. Technical field

The invention relates to an anaerobic sewage biological treatment device for treating sewage containing high-concentration sulfate and organic pollutants, in particular to a two-stage anaerobic digestion cycle blow-off system.

2. Background technology

The wastewater produced by pharmaceutical, chemical and food processing enterprises often contains not only high concentrations of organic matter, but also a large amount of sulfate, such as fermentation, starch, papermaking, leather, pharmaceuticals and other industries. Sulphate wastewater will acidify the receiving water body and endanger aquatic organisms; it will destroy the soil structure, make the soil harden, reduce the yield of crops and reduce the quality of agricultural products; at the same time, it will produce H ₂ S under the action of sulfate-reducing bacteria, and H ₂ S can corrode Pipeline equipment and pollute the atmosphere; groundwater in many cities in China has been polluted by sulfates to varying degrees. Using anaerobic method to treat high-concentration organic wastewater is currently the most cost-effective method, but in the presence of a large amount of sulfate, the traditional anaerobic system suffers from substrate competitive inhibition of sulfate-reducing bacteria on methanogens and SO ₄ ^{2 -} Reduction produces H ₂ S toxicity inhibition, low processing efficiency, and even can't run normally.

It is one of the keys to improve the treatment efficiency of anaerobic system to remove H ₂ S produced by SO ₄ ^2- reduction by air stripping. The single-phase anaerobic blow-off process is to install an inert gas blow-off device in the single-phase anaerobic treatment system to continuously blow off _H2S from the reactor, thereby improving the operating performance of the reactor, but in the reactor Continuous stripping is not conducive to the normal anaerobic digestion reaction and the formation of granular sludge, and it does not overcome the substrate competitive inhibition of sulfate-reducing bacteria on methanogens.

The two-phase anaerobic process promotes the acidification and sulfate reduction of microorganisms in the acidification unit, and the methanation in the methanation unit, which avoids the substrate competition between sulfate-reducing bacteria and methanogens. However, in the acidification unit, because there is no gas disturbance caused by the methanogenic process, H ₂ S is not easy to overflow, so the concentration of sulfide is high, which makes the microorganisms suffer from toxicity inhibition. Moreover, sulfate reduction in the acidification unit is usually not complete, and a large amount of sulfate still flows into the methanation unit, which adversely affects the methanation process.

Usually, the hydraulic ascending flow rate of the anaerobic reactor can be increased to improve the treatment efficiency, because the increase of the hydraulic ascending flow rate is conducive to the absorption of the substrate by sulfate-reducing bacteria and methanogenic bacteria, and promotes the sulfuric acid reduction and methanogenic reactions, and Stronger hydraulic disturbance also favors the escape of _H2S from the water. However, the H ₂ S concentration is still high, and the problem of substrate competition has not been resolved.

If the traditional anaerobic process can be optimized to overcome the substrate competitive inhibition of sulfate-reducing bacteria on methanogens and the toxicity inhibition of H ₂ S produced by SO ₄ ^2- reduction, the system will be able to achieve efficient and stable operation.

3. Contents of the invention

The purpose of the present invention is to design a kind of anaerobic microbial sewage treatment system that can reach the above-mentioned requirements and solve the above-mentioned problems. In the first-stage reactor, a larger hydraulic rising flow rate and hydraulic disturbance can be realized, and through muddy water circulation and The substrate adsorption tube improves the mass transfer efficiency of the substrate, so that most of the sulfate and organic matter are removed. At the same time, the concentration of H ₂ S is controlled by the biogas production process of the primary reactor and the external gas stripping of the secondary reactor. After the enhanced treatment of microorganisms in the secondary reactor, the system is stable and the effluent water quality is good.

The two-stage anaerobic digestion cycle blow-off system of the present invention, the main body is two sets of vertical cylinder structures, which are respectively a swirling anaerobic fluidized bed and a composite reactor, the bottom of the composite reactor is an inverted cone structure, and in addition It also includes water inlet pipes, water inlet pumps, fluidized bed outlet pipes, return pipes, circulation pumps, and reactor outlet pipes, wherein the water inlet pipes are arranged on the top of the swirling anaerobic fluidized bed through the water inlet pumps, and the fluidized bed outlet pipes are connected The swirling anaerobic fluidized bed is connected to the top of the compound reactor, and the return pipe is connected to the bottom of the compound reactor through the circulation pump to the top of the swirling anaerobic fluidized bed, and the outlet pipe of the reactor is arranged on the upper part of the compound reactor;

The swirling anaerobic fluidized bed includes a fluidized bed tank, a mixer, a substrate adsorption pipe, a swirling water distributor, an upflow chamber, a swirling baffle, a fluidized bed gas collecting hood, and a fluidized bed outlet tank; The swirling water distributor and the fluidized bed gas collection hood are respectively arranged at the bottom and top of the fluidized bed tank; the inlet of the mixer is below the fluidized bed gas collection hood and higher than the fluidized bed outlet tank, the water inlet pipe and the return pipe Extending into the mixer; the substrate adsorption tube is located in the center of the fluidized bed tank and communicates with the mixer and the swirl water distributor; the cavity between the outer wall of the substrate adsorption tube and the inner wall of the fluidized bed tank is an upflow chamber; The swirl baffle is arranged on the inner wall of the fluidized bed tank; the fluidized bed outlet tank is arranged on the upper part of the fluidized bed tank and communicates with the fluidized bed outlet pipe.

The composite reactor includes a reactor tank, a blow-off chamber, a microporous diffuser, an air inlet pipe, a sludge sedimentation area, a suspended active packing layer, a reactor gas collection hood, and a reactor outlet tank; the blow-off chamber is coaxially arranged on The middle and upper part of the reactor tank; the microporous diffuser is arranged horizontally in the middle and lower part of the stripping chamber, and communicates with the inlet pipe; the outlet pipe of the fluidized bed extends into the upper part of the stripping chamber; the sludge sedimentation area is set in the reactor tank The lower part of the reactor tank; the return pipe communicates with the bottom of the reactor tank; the suspended active packing layer is between the outer wall of the blow-off chamber and the inner wall of the reactor tank; the reactor gas collection hood is set on the top of the reactor tank; The upper part of the reactor tank is connected with the reactor outlet pipe. The water output of this system is stable, the concentration of sulfate and organic matter is greatly reduced, and the discharge can reach the standard after being treated by the aerobic system.

The working principle of the present invention: in the swirling anaerobic fluidized bed of the two-stage anaerobic digestion cycle stripping system, the raw water and the large amount of muddy water precipitated from the composite reactor are fully mixed in the mixer, and then passed through the substrate adsorption tube And the swirl water distributor enters the upflow chamber. The plug-flow form of the substrate adsorption tube is similar to a biological selector, which can generate a large substrate concentration gradient, promote the absorption of different anaerobic microorganisms with their respective competitive advantages in the raw water, and reduce the impact of sulfate-reducing bacteria on the production of methane. The matrix competitive inhibition of bacteria effectively improves the removal efficiency of sulfate and organic matter. When the mud-water mixture enters the upflow chamber through the swirl water distributor, it can generate a counterclockwise swirl at the bottom of the reactor, so that the sludge can be fully stirred to reduce the hydraulic dead zone, and strengthen the mixing contact of mud and water, preventing the reactor from The local concentration of H ₂ S at the bottom is too high. In order to maintain a certain hydraulic stirring intensity in the entire upflow chamber, two or more layers of swirl baffles are set according to the height of the reactor to enhance the disturbance effect. A large amount of muddy water circulated back from the bottom of the composite reactor provides sufficient hydraulic upflow velocity for the upflow chamber, making the sludge bed fluidized and creating good conditions for the efficient operation of the reactor. The biogas generated during the methanogenic process, combined with the hydraulic conditions of the fluidization state and swirl disturbance, promotes the overflow of H ₂ S gas from the water, effectively reducing the toxicity inhibition effect of H ₂ S in the reactor. The cyclone anaerobic fluidized bed does not use a three-phase separator, thereby increasing the effective volume of the reactor and improving the treatment efficiency of the reactor. The biogas produced by the reactor is collected by the gas collection hood and then desulfurized, and used as the stripping gas of the composite reactor.

The mud-water mixture flowing out of the swirling anaerobic fluidized bed first passes through the microporous diffuser in the blow-off chamber of the composite reactor to remove sulfur with biogas, and then enters the sludge sedimentation area for precipitation, and the clear liquid produced by the precipitation flows up to The secondary anaerobic suspended active filler layer is discharged after enhanced treatment, and the precipitated mud-water mixture is returned to the swirling anaerobic fluidized bed. Since the removal effect of the swirling anaerobic fluidized bed on H ₂ S is limited, and the concentration of H ₂ S cannot be controlled, a large proportion of the mud-water mixture flowing out of the swirling anaerobic fluidized bed is carried out in the compound reactor. Circulation stripping, by controlling the stripping gas volume and circulation ratio to limit the H ₂ S concentration within a certain range, to ensure that the system will not be affected by the toxicity of H ₂ S, and the stripping gas is the desulfurized gas of the biogas generated by the system. In view of the shortcomings of incomplete first-level anaerobic digestion of high-concentration pollutant wastewater, the suspended active filler layer uses anaerobic biofilm technology, which can greatly reduce the pollutant content of wastewater with lower concentration of pollutants after the first-level anaerobic treatment, and reduce the subsequent Aerobic facility handling pressure.

The swirl water distributor in the present invention is conical, and its surface is composed of a plurality of identical fan-shaped water distribution blades with the cone top as the center. The arc edges of the fan-shaped water distribution blades are closely connected with the inner wall of the fluidized bed tank, and It is connected to the bottom of the fluidized bed tank, and the other end is higher than the bottom of the fluidized bed tank by a certain distance, so that each fan-shaped water distribution blade forms a certain inclination angle with the conical surface, and there is a certain distance between every two adjacent fan-shaped water distribution blades. Angles overlap to form a gap towards the tangent direction of the round edge of the fluidized bed tank. The muddy water mixture flows out along the gap of the swirling water distributor, generating a counterclockwise tangential swirling water flow, so that the muddy water at the bottom of the reactor is fully stirred.

The above-mentioned swirl baffles are fixed on the inner wall of the fluidized bed tank, and two or more layers can be arranged at different heights in the fluidized bed tank, each baffle forms a certain angle with the bottom of the fluidized bed tank, and each The multi-layer baffles are evenly distributed at the same height of the inner wall of the fluidized bed tank, so that every two baffles form a cavity that rotates upwards counterclockwise toward the round edge of the fluidized bed tank, so that the upflow chamber The water flow is not vertically upward, but counterclockwise to flow upward, so as to achieve a certain hydraulic stirring effect. The projections of the adjacent two layers of baffles on the bottom of the fluidized bed tank complement each other to form concentric rings, which prevents the short flow of water from avoiding the baffles.

The two-stage anaerobic digestion cycle blow-off system of the present invention has the following characteristics: (1) Through the large-scale circulation of mud and water, the role of the swirl water distributor and the swirl baffle, the first-stage reactor can realize a relatively large hydraulic rising flow rate and The effect of hydraulic disturbance produces the state of sludge bed fluidization and swirling flow, and achieves good hydraulic mixing conditions. (2) Use the substrate adsorption tube to improve the substrate mass transfer efficiency, reduce the matrix competitive inhibition effect of sulfate-reducing bacteria on methanogens, and effectively improve the removal efficiency of sulfate and organic matter. (3) After part of the H ₂ S overflows through the biogas production process of the primary reactor, the additional desulfurization biogas gas stripping and stripping of the secondary reactor limits the concentration of H ₂ S within a certain range to ensure that the system is free from H ₂ S toxic effects. (4) The anaerobic biofilm process of suspending the active filler layer in the secondary reactor strengthens the treatment effect of the system and reduces the treatment pressure of the subsequent aerobic facilities. (5) The whole system has a stable treatment effect on high-concentration sulfate organic wastewater, with good effluent quality and low cost.

4. Description of drawings

Fig. 1 is a structural representation of the present invention;

Figure 2 is a schematic diagram of the installation of the swirl water distributor, where a is the front view and b is the top view;

Fig. 3 is a schematic structural view of the swirl baffle, wherein a is a front view, b is a top view of the first layer of swirl baffles, c is a top view of the second layer of swirl baffles, and d is an expanded view.

5. Specific implementation

In order to further illustrate the present invention, the specific implementation manners of the present invention will be described in detail below.

Fig. 1 is the structure diagram of the present invention, and it comprises water inlet pipe 1, water inlet pump 2, swirl type anaerobic fluidized bed 3, fluidized bed outlet pipe 4, composite reactor 5, return pipe 6, circulation pump 7, Reactor outlet pipe 8. The swirling anaerobic fluidized bed 3 and the composite reactor 5 are two sets of vertical cylindrical structures, and the bottom of the composite reactor is an inverted cone structure; the water inlet pipe 1 and the water inlet pump 2 are the raw water inlets of the system, and the At the front of the cyclone anaerobic fluidized bed 3; the reactor outlet pipe 8 is the final water outlet of the system, which is arranged at the rear of the composite reactor 5; the cyclone anaerobic fluidized bed 3 and the composite reactor 5 They are connected to each other through fluidized bed outlet pipe 4, return pipe 6 and circulation pump 7.

Among them, the swirling anaerobic fluidized bed 3 includes a fluidized bed tank 9, a mixer 10, a substrate adsorption tube 11, a swirling water distributor 12, an upflow chamber 13, a swirling baffle 14, and a fluidized bed Gas collecting hood 15, fluidized bed water outlet 16; the top and bottom of fluidized bed tank 9 are respectively swirl water distributor 12 and fluidized bed gas collecting hood 15, the upper part is fluidized bed water outlet 16, fluidized bed The water outlet tank 16 communicates with the fluidized bed outlet pipe 4; the mixer 10 is located below the fluidized bed gas collecting hood 15 and is higher than the fluidized bed outlet tank 16, and the water inlet pipe 1 and the return pipe 6 extend into the mixer 10; the substrate The adsorption pipe 11 is located at the center of the fluidized bed tank body 9, and its upper and lower parts are communicated with the mixer 10 and the swirl water distributor 12 respectively; the cavity between the substrate adsorption pipe 11 outer wall and the fluidized bed tank body 9 inner wall is liter Flow chamber 13; two layers of swirl baffles 14 are respectively arranged at 1/3 height and 2/3 height of the upflow chamber.

The composite reactor 5 includes a reactor tank body 17, a stripping chamber 18, a microporous diffuser 19, an air inlet pipe 20, a sludge sedimentation area 21, a suspended active packing layer 22, a reactor gas collection hood 23, and a reactor outlet Water tank 24; the center of the reactor tank 17 is a stripping chamber 18, the center is provided with a suspended active filler layer 22 outside, the upper part is provided with a reactor outlet tank 24, the top is provided with a reactor gas collection hood 23, and the lower part is a sludge sedimentation area 21, The bottom communicates with the return pipe 6; the microporous diffuser 19 communicated with the inlet pipe 20 is arranged in the middle and lower part of the stripping chamber 18; the fluidized bed outlet pipe 4 extends into the upper part of the stripping chamber 18.

Fig. 2 is a schematic diagram of the installation of the swirl water distributor. It can be seen from the figure that the swirl water distributor 12 is a conical structure, and its surface is composed of a plurality of identical fan-shaped water distribution blades 25 with the cone top as the center. The arc edge of the water distribution blade 25 is closely connected with the inner wall of the fluidized bed tank body 9, one end is connected to the bottom of the fluidized bed tank body 9, and the other end is higher than the bottom of the fluidized bed tank body 9 by a certain distance, so that each fan-shaped water distribution blade 25 forms a certain angle of inclination with the conical surface, and there is a certain angle of overlap between every two fan-shaped water distribution blades 25, forming a slit towards the counterclockwise tangential direction of the round edge of the fluidized bed tank body 9.

Fig. 3 is the structural representation of swirl baffle, as can be seen from the figure, described swirl baffle 14 is fixed on the inner wall of fluidized bed tank 9, and each baffle forms a certain gap with fluidized bed tank 9 bottoms. Included angle, the multiple baffles of each layer are evenly distributed at the same height of the inner wall of the fluidized bed tank 9, so that every two adjacent baffles form a counterclockwise upward direction towards the round edge of the fluidized bed tank 9. In the cavity, the projections of the adjacent two layers of baffles on the bottom of the fluidized bed tank 9 complement each other to form concentric rings.

Claims (4)

1. A two-stage anaerobic digestion cycle stripping system, characterized in that it includes a water inlet pipe (1), an inlet water pump (2), a swirling anaerobic fluidized bed (3), a fluidized bed outlet pipe (4 ), composite reactor (5), return pipe (6), circulation pump (7), reactor outlet pipe (8), and the water inlet pipe (1) is arranged in the cyclone anaerobic The top of the fluidized bed (3), the fluidized bed outlet pipe (4) connects the swirling anaerobic fluidized bed (3) to the top of the composite reactor (5), and the return pipe (6) passes through the circulation pump (7) The bottom of the composite reactor (5) is connected to the top of the swirling anaerobic fluidized bed (3), and the reactor outlet pipe (8) is arranged on the top of the composite reactor (5); The swirling anaerobic fluidized bed (3) includes a fluidized bed tank (9), a mixer (10), a substrate adsorption pipe (11), a swirling water distributor (12), an upflow chamber (13), Swirl baffle (14), fluidized bed gas collection cover (15), fluidized bed outlet tank (16); swirl water distributor (12) is arranged at the bottom of fluidized bed tank (9); fluidized bed The gas collecting hood (15) is arranged on the top of the fluidized bed tank body (9); the inlet of the mixer (10) is below the fluidized bed gas collecting hood (15) and higher than the fluidized bed outlet tank (16), The water inlet pipe (1) and the return pipe (6) extend into the mixer (10) respectively and discharge the raw water and the muddy water mixture; the substrate adsorption pipe (11) is located at the center of the fluidized bed tank (9), and its upper part is connected with the mixer. The bottom of (10) is communicated, and the bottom is communicated with the top of cyclone water distributor (12); The cavity between the outer wall of substrate adsorption pipe (11) and the inner wall of fluidized bed tank (9) is the upflow chamber (13) The swirl baffle (14) is fixed on the inner wall of the fluidized bed tank (9); the fluidized bed outlet tank (16) is located on the top of the fluidized bed tank (9) and is connected with the fluidized bed outlet pipe ( 4) connectivity; The composite reactor (5) comprises a reactor tank body (17), a stripping chamber (18), a microporous diffuser (19), an air inlet pipe (20), a sludge settling area (21), a suspended active packing layer ( 22), reactor gas collecting hood (23), reactor water outlet tank (24); the blow-off chamber (18) is coaxially arranged in the middle and upper part of the reactor tank (17); the microporous diffuser (19) is arranged horizontally In the stripping chamber (18) and communicated with the inlet pipe (20); the fluidized bed outlet pipe (4) stretches into the top of the stripping chamber (18); the sludge settling area (21) is arranged on the reactor tank body (17 ); the return pipe (6) communicates with the bottom of the reactor tank (17); the suspended active packing layer (22) is between the outer wall of the stripping chamber (18) and the inner wall of the reactor tank (17); the reactor assembly The gas cover (23) is arranged on the top of the reactor tank body (17); the reactor water outlet tank (24) is arranged on the upper part of the reactor tank body (17) and communicates with the reactor water outlet pipe (8). 2. According to the two-stage anaerobic digestion cycle blow-off system according to claim 1, it is characterized in that the swirl water distributor (12) is conical, and its surface consists of a plurality of identical fan-shaped water distributors with the top of the cone as the center. Composed of blades (25), the arc edge of the fan-shaped water distribution blade (25) is closely connected with the inner wall of the fluidized bed tank (9), one end is connected to the bottom of the fluidized bed tank (9), and the other end is higher than the fluidized bed tank The bottom of the body (9) has a certain distance, so that each fan-shaped water distribution blade (25) forms a certain angle of inclination with the conical surface, and every two adjacent fan-shaped water distribution blades (25) overlap at a certain angle to form a direction The slit in the anticlockwise tangential direction of the round edge of the fluidized bed tank body (9). 3. The two-stage anaerobic digestion cycle blow-off system according to claim 1, characterized in that the swirl baffle (14) is fixed on the inner wall of the fluidized bed tank (9), and can be placed on the fluidized bed tank (9) Two or more layers are arranged at different heights, each baffle forms a certain angle with the bottom of the fluidized bed tank (9), and multiple baffles in each layer are evenly distributed on the fluidized bed tank (9) ) at the same height of the inner wall, so that every two baffles form a cavity that rotates upward toward the round edge of the fluidized bed tank (9) counterclockwise, and the adjacent two layers of baffles are at the bottom of the fluidized bed tank (9) The projections of are complementary to form concentric rings. 4. The two-stage anaerobic digestion cycle stripping system according to claim 1 or 2, characterized in that the swirl baffles (14) are two layers, respectively located at 1/3 height of the upflow chamber (13) and 2/3 high.

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