Double-layer cover pre-aeration tank, biochemical waste gas treatment system and process

Abstract

This invention relates to a double-layered sealed pre-aeration tank, comprising a pre-aeration tank body and a pre-aeration tank cover. The pre-aeration tank cover is a hollow cover formed by an inner cover and an outer cover, and is fixedly connected to the pre-aeration tank body. The inner cover has at least one vent hole for connecting the hollow cover body and the pre-aeration tank body, and the outer cover has at least one vent hole for gas to pass through the hollow cover body. This invention can utilize existing pre-aeration tanks for modification, eliminating the malodorous odor generated during wastewater aeration, with good effect and simple operation. Simultaneously, the double-layered sealing helps improve the oxygen utilization rate in the pre-aeration tank, ensuring the initial degradation of wastewater by activated sludge in the tank. This not only accelerates the degradation of malodorous components in the waste gas but also accelerates the degradation of harmful substances in the wastewater, resulting in good pollutant degradation effect. This invention also provides a biochemical waste gas treatment system and process.

Description

Technical Field

[0001] This invention belongs to the field of waste gas treatment technology, and in particular relates to a device, system and process for treating fugitive emissions of waste gas during the biochemical treatment of biopharmaceutical wastewater. Background Technology

[0002] Chemical and biopharmaceutical processes generate large amounts of wastewater, including production wastewater from products such as 6-aminopenicillin, chlortetracycline, avermectin, coenzyme Q10, amoxicillin, ampicillin, piperacillin, and sulbactam. This wastewater is typically collected at the industrial park's wastewater treatment plant for pretreatment and biochemical treatment to meet industrial discharge requirements. Because this wastewater has a complex composition, containing sulfate, various organic compounds, alcohols, hydrogen sulfide, and unused fermentation materials, the treatment process generates fugitive emissions of malodorous gases. This not only negatively impacts human and animal health but also pollutes the soil and environment, severely affecting the lives of residents near the factory.

[0003] With the increasing awareness of environmental protection in society, major wastewater treatment plants have gradually adopted treatment measures. Currently, the common treatment method involves collecting waste gas and then reducing the concentration of odorous gases through various measures such as alkaline scrubbing absorption, incineration, and catalytic oxidation before discharge. While one or a combination of these waste gas treatment processes can effectively improve the environment, they also present problems such as high investment, high operating costs, complex processes, increased enterprise costs, and secondary pollution from the use of chemicals, which can seriously affect enterprises' enthusiasm for implementing environmental governance measures. Therefore, finding a simple, convenient, low-investment, effective treatment process that does not generate secondary pollution meets the needs of industry development. Summary of the Invention

[0004] The purpose of this invention is to address the deficiencies and shortcomings of existing technologies by providing a double-layer sealed pre-aeration tank, a biochemical waste gas treatment system and process for the treatment of fugitive emissions during the biochemical treatment of industrial wastewater. This system not only satisfies the purpose of pre-aeration in wastewater treatment but also effectively prevents malodorous gases from being emitted into the atmosphere during the pre-aeration process. Furthermore, it degrades and purifies the fugitive emissions generated during the pre-aeration process to meet industrial emission standards.

[0005] To achieve the above objectives, the present invention provides a double-layer sealed pre-aeration tank, comprising a pre-aeration tank body and a pre-aeration tank cover. The pre-aeration tank cover is a hollow cover formed by an inner cover and an outer cover. The pre-aeration tank cover is fixedly connected to the pre-aeration tank body. The inner cover has at least one ventilation hole for connecting the hollow cover body and the pre-aeration tank body. The outer cover has at least one air outlet for gas to pass through the hollow cover body.

[0006] According to one aspect of the present invention, the pre-aeration tank cover and the pre-aeration tank body are sealed and fixedly connected, and the sealing material is an adhesive material, preferably an acrylic structural adhesive, a two-component polyurethane structural adhesive, and more preferably a two-component polyurethane.

[0007] According to one aspect of the present invention, the inner cover and the outer cover are one or more integrally formed structures or multiple separate structures, and the joints between adjacent inner covers and outer covers, between inner covers and inner covers, and between outer covers and outer covers are sealed and connected, preferably by using sealing gaskets and fixing them with bolts or buckles.

[0008] According to one aspect of the present invention, the inner cover has one or more drainage holes communicating with the pre-aeration tank body at the lowest point of the bottom of the pre-aeration tank body; the drainage holes are circular, rectangular, square or irregular in shape, preferably circular, and the diameter of the drainage holes is 10-50 mm.

[0009] According to one aspect of the invention, the drain holes are formed at the edge of the inner cover, preferably distributed on opposite sides of the inner cover.

[0010] According to one aspect of the invention, the longitudinal cross-section of the inner and / or outer caps is semi-elliptical, semi-circular, arc-shaped, or triangular.

[0011] According to one aspect of the present invention, the vent is located on the top of the outer cover, and the cross-section of the vent is elliptical, circular, arc-shaped, square, or irregular, preferably circular, and the diameter of the vent is 100-200 mm.

[0012] According to one aspect of the invention, the vent hole at the top of the outer cover is offset from the vent hole and / or drain hole at the top or near the top of the inner cover below the vent hole, with a horizontal distance of 0.1-1m, preferably 0.5-1m.

[0013] According to one aspect of the invention, a waste gas collection device is fixedly and sealed at the vent hole on the outer cover for collecting waste gas from the pre-aeration tank cover.

[0014] According to one aspect of the present invention, the height difference between the center of the concave surface of the inner cap and the edge of the inner cap is 30-100cm, preferably 50cm; the height difference h1 between the center of the concave surface of the outer cap and the center of the inner surface of the inner cap is 50-100cm, preferably 80cm.

[0015] According to one aspect of the present invention, the pre-aeration tank body is further provided with a first sludge return pipe for providing return sludge, preferably activated sludge from a sedimentation tank, to the double-layer sealed pre-aeration tank.

[0016] According to one aspect of the invention, the returned sludge is distributed and returned to the inlet to outlet of the double-layer sealed pre-aeration tank through multiple points. Preferably, the proportion of returned sludge at the inlet to outlet is allocated according to the pollutant concentration gradient distribution in the wastewater from the inlet to the outlet of the double-layer sealed pre-aeration tank. More preferably, the returned sludge is distributed and returned to the inlet to outlet of the double-layer sealed pre-aeration tank through multiple points, with the return proportion at the inlet accounting for 40-50% of the sludge return flow and the return proportion at the outlet accounting for 3-5% of the sludge return flow.

[0017] According to one aspect of the present invention, a first wastewater inlet pipe and a first wastewater outlet pipe are installed on the wall of the pre-aeration tank; the wastewater comes from wastewater or wastewater mixtures received from the plant area or external sources; the wastewater treated by the double-layer sealed pre-aeration tank enters the subsequent process for further treatment.

[0018] According to one aspect of the invention, a first aeration device is installed in the pre-aeration tank for aerating air into the double-sealed pre-aeration tank.

[0019] According to one aspect of the present invention, the sealing material is selected from corrosion-resistant materials, preferably fiberglass.

[0020] According to one aspect of the present invention, the waste gas collection device includes a first waste gas collection pipe, a second waste gas collection pipe and a first induced draft fan connected in sequence, wherein the air inlet end of the first waste gas collection pipe is in sealed communication with the air outlet on the outer cover of the double-layer sealed pre-aeration tank.

[0021] According to one aspect of the present invention, a first cyclone separator and a third waste gas collection pipe are sequentially connected between the second waste gas collection pipe and the first induced draft fan. The outlet end of the first cyclone separator is connected to the inlet end of the third waste gas collection pipe. The liquid separated by the first cyclone separator returns to the double-layer sealed pre-aeration tank through the pre-aeration tank cover and / or the pre-aeration tank body via a first cyclone return pipe connected to the first cyclone separator.

[0022] According to one aspect of the present invention, the inlet end of the first exhaust gas collection pipe and the outlet hole are sealed and fixedly connected by a sealing gasket, wherein the sealing gasket is an adhesive material, preferably an acrylic structural adhesive, a two-component polyurethane structural adhesive, and more preferably a two-component polyurethane.

[0023] According to one aspect of the present invention, the inlet end of the first exhaust gas collection pipe is sealed and fixedly connected to the protrusion provided on the outside of the pool cover, and the sealing gasket is an adhesive material, preferably an acrylic structural adhesive, a two-component polyurethane structural adhesive, and more preferably a two-component polyurethane.

[0024] The present invention also provides a biochemical waste gas treatment system, comprising a double-layer sealed pre-aeration tank, an aerobic tank, and a waste gas emission device as described in any of the above-mentioned embodiments, connected in sequence. The top of the cover of the aerobic tank is provided with at least one exhaust hole, and the waste gas emission device is installed at the exhaust hole.

[0025] According to one aspect of the present invention, the aerobic tank is a spray aerobic tank, comprising an aerobic tank body, an aerobic tank cover, and a sludge spraying device. The aerobic tank cover is sealed and fixedly connected to the aerobic tank body, and the sludge spraying device is connected to the aerobic tank cover for spraying activated sludge into the spray aerobic tank.

[0026] According to one aspect of the present invention, the sludge spraying device sprays activated sludge onto the exhaust gas above the liquid surface in the aerobic spraying tank to form primary degradation exhaust gas.

[0027] According to one aspect of the present invention, the sludge spraying device includes a spray liquid suction pipe, a sludge spraying pump, a sludge spraying main pipe, a sludge spraying branch pipe, and a sludge spraying head connected in sequence. The inlet end of the spray liquid suction pipe is submerged below the liquid surface in the aerobic spraying tank, preferably located at the bottom of the aerobic spraying tank near the tank wall, and more preferably near the wastewater outlet end at the bottom of the aerobic tank.

[0028] According to one aspect of the invention, the sludge spray head is an atomizing spray head.

[0029] According to one aspect of the present invention, a sludge spray branch pipe is further connected between the sludge spray branch pipe and the sludge spray head. The sludge spray branch pipe is divided into one or more branches in the horizontal direction and distributed below the aerobic tank cover, preferably evenly distributed below the aerobic tank cover at a distance of 1-3m from the liquid surface of the spray aerobic tank.

[0030] According to one aspect of the invention, the inlet end of the spray liquid suction pipe is further connected to a spray liquid filtration device to filter out blockages entering the spray liquid suction pipe; the blockages are garbage, leaves, or large particles of debris.

[0031] According to one aspect of the present invention, the spray liquid filtration device is a cylindrical, spherical or cuboid stainless steel cage, the cage having a plurality of filter holes distributed thereon, and preferably, at least one layer of stainless steel mesh is wrapped around the outside of the cage.

[0032] According to one aspect of the present invention, a branch valve, a pressure gauge or flow meter, and a branch filter are sequentially installed on the pipeline exposed above the aerobic tank cover of the sludge spray branch pipe, wherein the pressure gauge or flow meter and the branch filter are detachably installed on the sludge spray branch pipe.

[0033] According to one aspect of the present invention, a viewing mirror is provided on the cover of the aerobic tank for observing the sludge spray head inside the aerobic tank.

[0034] According to one aspect of the invention, the spray aerobic tank further includes an exhaust gas aeration device for aerating exhaust gas into the spray aerobic tank.

[0035] According to one aspect of the invention, the sludge spraying device in the aerobic spraying tank sprays the activated sludge with the waste gas input from the waste gas aeration device to form primary degradation waste gas.

[0036] According to one aspect of the present invention, the waste gas aeration device is connected to the waste gas collection device described above, and the waste gas received from the double-layer sealed pre-aeration tank is input into the spray aerobic tank through the first induced draft fan, wherein the wind pressure of the first induced draft fan is 3-60 kPa.

[0037] According to one aspect of the present invention, the waste gas aeration device includes a waste gas aeration main pipe, a waste gas aeration main pipe, a waste gas aeration branch pipe, a waste gas aeration branch pipe, and a waste gas aeration head connected in sequence, for inputting waste gas into the aerobic tank.

[0038] According to one aspect of the invention, the exhaust gas aeration heads are distributed 0.3-5.0m below the wastewater surface in the aerobic tank.

[0039] According to one aspect of the present invention, the aerobic tank is further provided with a second wastewater inlet pipe and a second wastewater outlet pipe on the tank wall, wherein the second wastewater is a mud-water mixture from the sedimentation tank.

[0040] According to one aspect of the present invention, the aerobic tank is further provided with a second aeration device for aerating air into the spray aerobic tank.

[0041] According to one aspect of the invention, a waste gas emission device is fixedly and sealed to the vent hole on the aerobic tank cover for collecting and treating the primary degradation waste gas escaping from the spray aerobic tank.

[0042] According to one aspect of the present invention, the exhaust gas emission device comprises an exhaust gas collection device, an alkaline spray tower, a water spray box, a second induced draft fan, and an venting chimney connected in sequence.

[0043] According to one aspect of the present invention, the exhaust gas collection device includes a first gas collection pipe, a second gas collection pipe and a second cyclone separator connected in sequence, wherein the inlet end of the first gas collection pipe is fixedly and sealedly connected to the exhaust hole on the aerobic tank cover.

[0044] According to one aspect of the invention, the second gas collecting pipe collects gas from the first gas collecting pipe and sends it into the second cyclone separator.

[0045] According to one aspect of the invention, a third gas collecting pipe is connected to the outlet end of the second hydrocyclone, and the liquid separated by the second hydrocyclone is returned to the spray aerobic tank and / or the double-layer sealed pre-aeration tank through a second hydrocyclone return pipe connected to the second hydrocyclone.

[0046] According to one aspect of the invention, the second cyclone separator is one unit or multiple units connected in sequence, and the air pressure of the second induced draft fan is 1.0-3.0 kPa.

[0047] According to one aspect of the invention, the second cyclone return pipe is connected to the second return pipe to return the liquid separated by the second cyclone separator to the spray aerobic tank and / or the double-layer sealed pre-aeration tank.

[0048] According to one aspect of the invention, the liquid separated by the first cyclone separator on the waste gas collection device is returned to the aerobic spray tank through a first return pipe and / or a first return branch pipe connected to the first cyclone return pipe.

[0049] According to one aspect of the invention, in the alkali spray tower, the waste gas from the third gas collecting pipe is subjected to alkali spraying through the alkali solution sprayed from the top of the alkali spray tower to form secondary degradation waste gas.

[0050] According to one aspect of the present invention, the secondary degradation waste gas escapes from the top or upper part of the alkali spray tower and enters the alkali spray tower gas collection pipe. The liquid that has been alkali sprayed enters the second return pipe from the alkali spray tower liquid collection pipe at the bottom of the alkali spray tower and returns to the spray aerobic tank and / or the double-layer sealed pre-aeration tank.

[0051] According to one aspect of the invention, an online pH detector for waste gas is installed on the pipeline from the third gas collecting pipe into the alkali spray tower and on the pipeline from the alkali spray tower gas collecting pipe out of the alkali spray tower.

[0052] According to one aspect of the invention, the exhaust gas has a pH of 5.5-6.0 before entering the alkali spray tower and a pH of 6.8-7.2 after leaving the alkali spray tower.

[0053] According to one aspect of the present invention, the water spray box washes the secondary degradation waste gas from the gas collection pipe of the alkali spray tower with water sprayed from the top of the water spray box, and adjusts the pH of the washing gas to neutral.

[0054] According to one aspect of the invention, the washing gas is selected from the top or upper part of the water spray tank and enters the water spray tank gas collection pipe, and the washed liquid enters the second return pipe from the water spray tank liquid collection pipe at the bottom of the water spray tank and returns to the spray aerobic tank and / or the double-layer sealed pre-aeration tank.

[0055] According to one aspect of the present invention, an online exhaust gas pH detector is installed on the pipe leading out of the water spray box from the gas collection pipe of the water spray box.

[0056] According to one aspect of the invention, the second induced draft fan delivers the scrubbing gas from the water spray box gas collection pipe to the vent chimney for discharge.

[0057] The present invention also provides a biochemical waste gas treatment process utilizing the biochemical waste gas treatment device described in any one of the above claims, comprising the following steps:

[0058] Step S1: Aerate the injected organic wastewater in a double-layer sealed pre-aeration tank;

[0059] Step S2: Start the waste gas collection device to collect the waste gas in the double-layer sealed pre-aeration tank, and input it into the sealed aerobic tank to react with the sludge in the aerobic tank to obtain primary degradation waste gas;

[0060] Step S3: The primary degradation waste gas is collected and purified by the waste gas emission device before being discharged.

[0061] According to one aspect of the present invention, in step S1, activated sludge is injected into the double-layer sealed pre-aeration tank, wherein the activated sludge performs preliminary degradation on the injected organic wastewater, preferably activated sludge from a settling tank; the cover of the double-layer sealed pre-aeration tank is sealed and fixedly connected to the pre-aeration tank body.

[0062] According to one aspect of the invention, the activated sludge in the double-layer sealed pre-aeration tank is recirculated to maintain the activated sludge concentration in the pre-aeration tank while reducing the impact of high-concentration wastewater on the pre-aeration tank.

[0063] According to one aspect of the present invention, the activated sludge return is a partial return from the first wastewater effluent pipe to the double-layer sealed pre-aeration tank via the sludge return pipe of the double-layer sealed pre-aeration tank, preferably a return to the vicinity of the inlet where the first wastewater inlet pipe enters the double-layer sealed pre-aeration tank.

[0064] According to one aspect of the invention, the air outlet at the top of the outer cover of the double-layer sealed pre-aeration tank is staggered with the air vent and / or drain hole at the top or near the top of the inner cover below the air outlet, preferably with a horizontal distance of 10cm-1m between the two holes.

[0065] According to one aspect of the present invention, the liquid carried by the waste gas generated in step S1 condenses on the inner surface of the cover of the double-layer sealed pre-aeration tank and flows back to the double-layer sealed pre-aeration tank through a drain hole on the inner cover, the drain hole having a diameter of 10-50 mm.

[0066] According to one aspect of the invention, the drain holes are formed at the edge of the inner cover, preferably distributed on opposite sides of the inner cover.

[0067] According to one aspect of the present invention, in step S2, waste gas is collected from the air outlet at the top of the outer cover of the double-layer sealed pre-aeration tank, the aerobic tank is a spray aerobic tank, and the waste gas reacts with the sludge sprayed by the sludge spraying device in the spray aerobic tank to obtain primary degradation waste gas; the aerobic tank cover is sealed and fixedly connected to the aerobic tank body.

[0068] According to one aspect of the invention, the sludge is sprayed onto the exhaust gas entering the aerobic spray tank through the atomizing spray head of the sludge spraying device.

[0069] According to one aspect of the invention, the first induced draft fan of the waste gas collection device is started, and waste gas is aerated into the spray aerobic tank through the waste gas aeration device, wherein the wind pressure of the first induced draft fan is 3-60 kPa.

[0070] According to one aspect of the present invention, the waste gas aeration device includes a waste gas aeration main pipe, a waste gas aeration main pipe, a waste gas aeration branch pipe, a waste gas aeration branch pipe, and a waste gas aeration head connected in sequence. The waste gas aeration head is distributed 0.3-5.0m below the wastewater surface in the aerobic tank, and waste gas is aerated into the aerobic tank through the waste gas aeration head.

[0071] According to one aspect of the invention, before entering the first induced draft fan, the exhaust gas passes through a first hydrocyclone for gas-liquid separation, and the separated liquid returns to the double-layer sealed pre-aeration tank through a first cyclone return pipe connected to the first hydrocyclone and / or the pre-aeration tank body via the pre-aeration tank cover and / or the pre-aeration tank body.

[0072] According to one aspect of the invention, the sludge spraying pump installed on the sludge spraying device draws activated sludge for spraying from the bottom of the aerobic tank, preferably near the wastewater outlet end at the bottom of the aerobic tank.

[0073] According to one aspect of the invention, the activated sludge for spraying is filtered by a spray liquid filtration device before entering the sludge spraying pump to remove blockages from the spray liquid suction pipe.

[0074] According to one aspect of the invention, the sludge-water mixture in the aerobic spray tank originates from a sedimentation tank.

[0075] According to one aspect of the present invention, the sludge spraying branch pipe of the sludge spraying device is provided with a branch pipe valve, a pressure gauge or flow meter, and a branch pipe filter in sequence and detachably installed on the pipe exposed above the aerobic tank cover, and the pressure gauge pressure or flow meter flow rate is monitored to determine whether the sludge spraying branch pipe is blocked.

[0076] According to one aspect of the invention, the aeration device aerates air into the aerobic tank and the double-sealed pre-aeration tank.

[0077] According to one aspect of the present invention, in step S3, the primary degradation waste gas is drawn in by a second induced draft fan, first separated from the liquid carried by the waste gas collection device, then enters the alkaline spray tower for alkaline washing and deacidification, then enters the water spray tank for water washing, and finally is discharged through the venting chimney.

[0078] According to one aspect of the invention, the liquid carried in the primary degradation waste gas is separated by one or more second hydrocyclones connected in sequence and returned to the double-layer sealed pre-aeration tank and / or spray aerobic tank, wherein the air pressure of the second induced draft fan is 1.0-3.0 kPa.

[0079] According to one aspect of the invention, the liquid subjected to alkaline spraying and / or water washing is returned to the sprayed aerobic tank and / or the double-layer sealed pre-aeration tank.

[0080] According to one aspect of the present invention, the amount of alkaline spraying and water washing is adjusted by detecting the pH value in the exhaust gas. After alkaline spraying, the pH of the primary degradation exhaust gas is adjusted from 5.5-6.0 to 6.8-7.2, and after water washing, the pH of the washing gas is adjusted to neutral.

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] 1) This invention can modify existing wastewater treatment plant pre-aeration tanks by adding double-layer covers to create double-layer covered pre-aeration tanks, and modify existing wastewater treatment plant aerobic tanks by adding covers to create spray aerobic tanks. By sealing with conventional sealing materials, the problem of fugitive exhaust gas emissions caused by aeration during the treatment of high-concentration organic wastewater in the pre-aeration tank and aerobic tank is eliminated. The malodorous odor is eliminated on-site, especially during the mixing and pretreatment of biopharmaceutical fermentation mixed wastewater in the pre-aeration tank, where chemical reactions during wastewater mixing and aeration produce malodorous gases. The invention has low investment, good effect, and simple process operation.

[0083] 2) The double-layer sealed pre-aeration tank of the present invention, through double-layer sealing, creates a height difference between the center of the concave surface of the inner cover and the edge of the inner cover, forming a higher center and lower periphery, which is conducive to the rapid collection of waste gas generated inside the pre-aeration tank; the center of the concave surface of the outer cover and the center of the inner surface of the inner cover maintain a height difference, firstly ensuring that the hollow cover has sufficient cavity to buffer the air pressure inside the sealed pre-aeration tank, preventing excessive changes in air pressure inside the pre-aeration tank due to negative pressure suction after the induced draft fan is turned on, which would cause drastic changes in dissolved oxygen concentration and affect the pre-aeration treatment effect; secondly, compared with single-layer sealing, the double-layer sealing improves the pressure resistance. Firstly, the double-layered sealing appropriately increases the air pressure inside the pre-aeration tank, which helps improve the utilization rate of oxygen in the tank and ensures that the activated sludge with microbial communities in the tank can perform preliminary degradation of wastewater, resulting in more pollutant degradation. In actual use, it is more effective than a single-layered sealing structure. Secondly, pre-aeration can also transfer some volatile organic pollutants and recalcitrant organic components from the liquid phase to the gas phase. Through the diversion of pollutants, the wastewater treatment pressure in the pre-aeration tank is reduced. Furthermore, the waste gas is diverted and treated by a waste gas collection device, and then enters the downstream spray aerobic tank for forced aerobic biological treatment. This not only accelerates the degradation of waste gas but also accelerates the degradation of harmful substances in the wastewater.

[0084] 3) This invention recirculates activated sludge from a double-layered sealed pre-aeration tank to maintain a relatively stable activated sludge concentration, while reducing the impact of high-concentration wastewater on the pre-aeration tank, thus promoting stable operation. The pre-aeration tank employs a multi-point distributed recirculation design, increasing the recirculation flow rate at areas with high pollutant concentrations (i.e., the inlet) and decreasing the recirculation flow rate at areas with low pollutant concentrations (i.e., the effluent). This ensures that the activated sludge concentrations at the inlet and outlet of the double-layered sealed pre-aeration tank are nearly identical, resulting in better pollutant removal than conventional single-point recirculation and improved activated sludge degradation.

[0085] 4) In the double-layer sealed pre-aeration tank of the present invention, the air outlet at the top of the outer cover and the ventilation hole and / or drainage hole at the top of the inner cover below the air outlet are staggered, maintaining a horizontal distance of 0.1-1m between the two holes. This prevents short-circuiting of airflow between the two covers, which would reduce the pre-aeration exhaust gas treatment effect. Simultaneously, it facilitates the generation of condensate on the inner surface of the hollow cover when the exhaust gas entering the double-layer sealed pre-aeration tank is obstructed by the staggered connection between the two covers, reducing the pressure on the downstream induced draft fan, mitigating corrosion of the fan components, extending the fan's lifespan, reducing the fan failure rate, and decreasing material consumption in the next process.

[0086] 5) The double-layer sealed pre-aeration tank of the present invention can adopt an elliptical, semi-circular or arc-shaped structure in the longitudinal cross-section of the outer and inner seals, which can avoid the problem of poor operation due to dead airflow and cracking due to uneven pressure on the outer and inner seals.

[0087] 6) The double-layered pre-aeration tank of this invention has a drainage hole at the lowest point or near the lowest point of the inner cover edge. This hole recovers the condensate from the exhaust gas entering the hollow cover back to the pre-aeration tank. Hydrocyclones are installed on the exhaust gas collection and discharge devices to separate the liquid carried in the exhaust gas, reducing the pressure on the downstream induced draft fan, mitigating corrosion of the fan components, extending the fan's lifespan, reducing the fan failure rate, and simultaneously reducing material consumption in the next process. Furthermore, the liquid separated by the first hydrocyclone returns to the pre-aeration tank through the pre-aeration tank cover via a first hydrocyclone return pipe connected to the first hydrocyclone, allowing the drainage hole to be naturally cleaned using the condensate separated by the first hydrocyclone.

[0088] 7) An air aeration device is installed at the bottom of the aerobic tank of this invention. Air enters the aerobic tank through this aeration device, and the aerobic sludge degrades COD, nitrogen oxides, sulfides, etc. in the wastewater in an aerobic environment. Simultaneously, the microorganisms absorb, decompose, and transform odor-causing substances in the aerated waste gas, achieving further degradation of harmful substances in the waste gas and improving the waste gas treatment effect. The aerobic tank not only continuously provides microbial communities for wastewater and waste gas treatment, ensuring the continuity of waste gas treatment, but also eliminates the need for additional addition of new microbial communities and nutrients, resulting in low operating costs.

[0089] 8) The spray aerobic tank of the present invention can also fully agitate the wastewater in the tank by using dual aeration of waste gas and air, allowing some of the malodorous gases that have not been degraded in time to escape from the liquid surface and then come into contact with the spray sludge above the tank for further degradation, thereby improving the degradation effect of waste gas in wastewater.

[0090] 9) The spray aerobic tank of the present invention uses atomized spray heads to spray sludge, which can increase the contact area between the sprayed activated sludge and the waste gas. During the liquid-gas contact process, the atomized sludge further degrades the harmful substances in the waste gas escaping from the liquid surface, achieving a better waste gas treatment effect.

[0091] 10) The activated sludge used for spraying in this invention undergoes two-stage filtration: a spray liquid filtration device and a branch pipe filter, before spraying. This filters out debris, leaves, large particles, and other blockages that enter the spray branch pipes and spray heads, protecting the atomizing spray heads and improving the stable operation of the system.

[0092] 11) The spray branch pipes and atomizing spray heads of the present invention are arranged in multiple and evenly under the aerobic tank cover, which can increase the liquid-gas contact area between the waste gas and the activated sludge and improve the spray treatment effect on degrading the waste gas.

[0093] 12) The pressure gauge or flow meter, branch filter and atomizing spray head installed on the spray branch pipe of the present invention are all connected by a union, which facilitates maintenance or replacement. When the pressure gauge shows that the pressure has increased or the flow meter shows that the flow has decreased, it can be determined that the atomizing spray nozzle of the branch pipe is blocked. At this time, the valve on the branch can be closed for maintenance or replacement, which improves work efficiency.

[0094] 13) The present invention equips the aerobic tank cover near each atomizing spray nozzle group with a sight glass, which allows direct observation of the flow rate of the atomizing spray nozzle and also determines whether the atomizing spray nozzle is blocked, facilitating maintenance or replacement, avoiding the need for periodic disassembly of the sludge spray head for inspection, and improving work efficiency.

[0095] 14) In this invention, acidic substances such as H2S and odor-causing substances that can be absorbed by alkaline solution are removed from the primary degradation waste gas by alkaline spraying, thereby achieving further purification of the waste gas; after alkaline spraying, the pH of the waste gas is adjusted from 5.5-6.0 to 6.8-7.2, and after washing with water, the pH of the washing gas is adjusted to neutral.

[0096] 15) After the waste gas treatment process of the present invention, the odor concentration of the waste gas generated in the pre-aeration tank is 2000-2400 (dimensionless), and the odor concentration at the outlet of the final chimney is reduced to 200-300 (dimensionless), and the odor treatment effect is obvious.

[0097] 16) The waste gas treatment process of the present invention can not only solve the technical defects of the simple alkaline spraying treatment of waste gas with insignificant effect, but also solve the problems of large investment, high operating cost and complicated operation of traditional incineration, catalytic oxidation, biological method and other one or more combined processes, thereby reducing enterprise costs and reducing secondary pollution generated in the use of chemical reagents. Attached Figure Description

[0098] Figure 1 A schematic diagram of the double-layer sealed pre-aeration tank structure according to Embodiment 1;

[0099] Figure 2 An enlarged schematic diagram of point A in the double-layer sealed pre-aeration tank according to Embodiment 1;

[0100] Figure 3 A schematic diagram of the double-layer sealed pre-aeration tank structure according to Embodiment 2;

[0101] Figure 4 A schematic diagram of the double-layer sealed pre-aeration tank structure according to Embodiment 3;

[0102] Figure 5 A schematic diagram of the double-layer sealed pre-aeration tank structure according to embodiment 4;

[0103] Figure 6A schematic diagram of the double-layer sealed pre-aeration tank structure according to embodiment 5;

[0104] Figure 7 A schematic diagram of the double-layer sealed pre-aeration tank structure according to embodiment 6;

[0105] Figure 8 A schematic diagram of the double-layer sealed pre-aeration tank structure according to Embodiment 7;

[0106] Figure 9 According to the schematic diagram of the double-layer sealed pre-aeration tank structure in Embodiment 8;

[0107] Figure 10 A top view of the two adjacent outer cover structures of the double-layer sealed pre-aeration tank in Schematic Embodiment 9;

[0108] Figure 11 A top view of the single cover plate structure of the double-layer sealed pre-aeration tank in Schematic Embodiment 9;

[0109] Figure 12 A top view illustrating the double-layer sealed pre-aeration tank sealing structure of embodiment 10;

[0110] Figure 13 A top view illustrating the double-layered pre-aeration tank cover structure of embodiment 11;

[0111] Figure 14 A schematic diagram of the double-layer sealed pre-aeration tank structure according to embodiment 12;

[0112] Figure 15 A schematic diagram of a biochemical waste gas treatment system and process flow according to an embodiment of the present invention;

[0113] Figure 16 According to the present invention Figure 15 A schematic diagram of a spray aerobic tank structure in one embodiment;

[0114] Figure 17 A schematic diagram of a biochemical waste gas treatment system and process flow according to another embodiment of the present invention;

[0115] Figure 18 According to the present invention Figure 17 A schematic diagram of a spray aerobic tank structure in one embodiment;

[0116] Figure 19 This invention illustrates the present invention. Figure 17 A top view of a waste gas aeration device and aeration pipeline structure according to an embodiment;

[0117] Figure 20 This invention illustrates the present invention. Figure 17 A top view of a sludge spraying device and spraying pipeline structure according to an embodiment.

[0118] In the diagram: 1. Double-layer sealed pre-aeration tank; 2. Spray aerobic tank; 3. Alkali spray tower; 4. Water spray box; 5. Second induced draft fan; 6. Induced draft pipe; 7. Vent chimney; 10. Pre-aeration tank body; 11. Pre-aeration tank cover; 12. Sealing gasket; 13. Bolt; 14. First aeration device; 15. First wastewater inlet pipe; 16. First wastewater outlet pipe; 17. Waste gas collection device; 18. Sealant; 19. First sludge return pipe; 20. Aerobic tank body; 21. Aerobic tank cover; 22. Waste gas aeration device; 23. Second wastewater inlet pipe; ... Second aeration device 24, second wastewater outlet pipe 25, first return pipe 26, first return branch pipe 27, waste gas collection device 28, sludge spraying device 29, alkali spraying tower liquid collection pipe 32, alkali spraying tower gas collection pipe 33, water spraying box liquid collection pipe 42, water spraying box gas collection pipe 43, inner cover 111, outer cover 110, drain hole 112, vent hole 113, protrusion 114, air outlet 115, joint 116, first aeration main pipe 141, first aeration branch pipe 142, first Aeration head 143, first waste gas collection pipe 171, second waste gas collection pipe 172, first cyclone separator 173, third waste gas collection pipe 174, first cyclone return pipe 175, first induced draft fan 176, protrusion 211, exhaust hole 212, sealing material 213, sealing gasket 214, snap fastener 215, waste gas aeration main pipe 220, waste gas aeration main pipe 221, waste gas aeration branch pipe 222, waste gas aeration branch pipe 223, waste gas aeration head 224, second aeration main pipe 241, second Aeration branch pipe 242, second aeration head 243, first air collecting pipe 281, second air collecting pipe 282, second hydrocyclone 283, third air collecting pipe 284, second hydrocyclone return pipe 285, waste liquid collection pipe 286, second return pipe 287, spray liquid filtration device 291, spray liquid suction pipe 292, sludge spray pump 293, sludge spray main pipe 294, sludge spray branch pipe 295, branch pipe valve 296, pressure gauge 297, sludge spray branch pipe 298, sludge spray head 299. Detailed Implementation

[0119] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0120] When describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" express orientations or positional relationships based on the orientations or positional relationships shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on the present invention.

[0121] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the embodiments of the present invention are not limited to the following embodiments.

[0122] Implementation Method 1

[0123] Figure 1 This is a schematic diagram of the double-layer sealed cover pre-aeration tank structure according to Embodiment 1 of the present invention. Figure 1 As shown, the double-layered pre-aeration tank 1 includes a pre-aeration tank body 10 and a pre-aeration tank cover 11. The pre-aeration tank cover 11 is a hollow cover formed by an inner cover 111 and an outer cover 110. The pre-aeration tank cover 11 and the pre-aeration tank body 10 are sealed and fixedly connected at the contact points using an adhesive material, preferably acrylic structural adhesive or two-component polyurethane structural adhesive, more preferably two-component polyurethane. A rectangular vent hole 113 is provided in the center of the inner cover 111, connecting the hollow cover body and the pre-aeration tank body 10. The cross-sectional area of ​​the vent hole 113 is 20-300 cm². 2 The top of the outer cover 110 has a vent 115 for the gas in the hollow cover to pass through. The cross-section of the vent 115 is circular, but it can also be elliptical, arc-shaped, square or irregular in shape. The diameter of the vent 115 is 100mm.

[0124] In embodiment 1, a first wastewater inlet pipe 15 and a first wastewater outlet pipe 16 are installed on the wall of the pre-aeration tank 10. A first aeration device 14 is installed inside the pre-aeration tank 10 to aerate air into the double-layer sealed pre-aeration tank 1. The first aeration device 14 includes a first aeration main pipe 141, a first aeration branch pipe 142, and a first aeration head 143 connected in sequence. The first aeration main pipe 141 is disposed on the wall of the pre-aeration tank 10. The first aeration branch pipe 142 communicates with the first aeration main pipe 141, extends into and is distributed at the bottom of the pre-aeration tank 10. The first aeration head 143 is connected to the first aeration branch pipe 142.

[0125] In Implementation Method 1, an existing pre-aeration tank in a wastewater treatment plant is modified. The pre-aeration tank 10 is cylindrical in shape, with part of the tank below ground level. It is fitted with a double-layer cover, with the inner cover 111 and the outer cover 110 being a single, integrally molded structure. The joint between the inner cover 111 and the outer cover 110 is sealed using conventional two-component polyurethane sealing material. Before the modification, high-concentration wastewater, especially mixed wastewater from biopharmaceutical fermentation, generated a large amount of malodorous gas during the mixing and pretreatment process in the pre-aeration tank due to chemical reactions during aeration. After the modification, the double-layer cover ensures a seal between the pre-aeration tank 10 and the pre-aeration tank cover 11, eliminating the problem of fugitive emissions during aeration when treating high-concentration organic wastewater. The malodorous odor is eliminated on-site. The project requires less investment in modification and emissions control, has good results, and is simple to operate.

[0126] In Implementation Method 1, the pre-aeration tank is sealed with a double-layer cover, which buffers the air pressure inside the sealed pre-aeration tank, ensuring that the dissolved oxygen concentration inside the tank does not fluctuate too much and affect the pre-aeration treatment effect. Furthermore, compared to a single-layer seal, the double-layer cover has increased pressure resistance, which can appropriately increase the air pressure inside the pre-aeration tank, helping to improve the oxygen utilization rate within the tank. This ensures that the activated sludge containing microbial communities in the tank can perform preliminary degradation of the wastewater, resulting in greater pollutant degradation. The actual performance is superior to a single-layer seal structure. Moreover, aeration can transfer some volatile organic pollutants and recalcitrant organic components from the liquid phase to the gas phase. This pollutant diversion reduces the wastewater treatment pressure in the pre-aeration tank, and the waste gas collection device achieves diversion treatment, directing the waste gas to the downstream waste gas treatment process. This not only accelerates the degradation of the waste gas but also accelerates the degradation of harmful substances in the wastewater.

[0127] In embodiment 1, the outer cover 110 has a protrusion 114 with openings at both ends at the air outlet 115 extending outwards from the pre-aeration tank cover 11. A waste gas collection device 17 is fixed at the air outlet 115 on the outer cover 110 to collect waste gas entering the pre-aeration tank cover 11. The waste gas collection device 17 includes a first waste gas collection pipe 171, a second waste gas collection pipe 172, and a first induced draft fan 176 connected in sequence. The air inlet end of the first waste gas collection pipe 171 is sealed and connected to the air outlet 115 on the outer cover 110 of the pre-aeration tank using sealant 18. The sealing material is an adhesive, preferably acrylic structural adhesive or two-component polyurethane structural adhesive, more preferably two-component polyurethane. During installation, the air inlet end of the first waste gas collection pipe 171 is inserted into the protrusion 114 on the outside of the pre-aeration tank cover 11 and fixed. The gap between them is sealed and connected using sealant 18, with the sealing material being two-component polyurethane. The first waste gas collection pipe 171 is a single pipe. The first induced draft fan has a wind pressure of 3-60 kPa.

[0128] In embodiment 1, the vent 115 at the top of the outer cover 110 and the vent 113 at the top or near the top of the inner cover 111 below the vent 115 are staggered, with a horizontal distance of 0.5m between the two vents. Therefore, when the first exhaust fan 176 is turned on and a negative pressure is formed in the first exhaust gas collection pipe 171 to draw in the exhaust gas generated in the pre-aeration tank, short-circuiting of the airflow between the two covers can be prevented, thus reducing the pre-aeration exhaust gas treatment effect. At the same time, the exhaust gas entering the hollow cover of the double-covered pre-aeration tank 1 is facilitated by the staggered obstruction of the connecting pipe holes of the two covers when entering the hollow cover, resulting in condensation on the inner surface of the hollow cover. This reduces the pressure on the rear exhaust fan, slows down the corrosion of the exhaust fan components, extends the life of the exhaust fan, reduces the fan failure rate, and reduces material consumption in the next process.

[0129] In embodiment 1, the double-layer sealed pre-aeration tank 1, the outer cover 110 and the inner cover 111 are designed as an arc-shaped structure with a high center and low edge in the longitudinal cross section. This can avoid the problem of airflow dead angles leading to poor operation when sucking up the waste gas generated in the pre-aeration tank, as well as the problem of the outer cover 110 and the inner cover 111 cracking due to uneven pressure.

[0130] In embodiment 1, the height difference between the center of the concave surface of the inner cover 111 and the edge of the inner cover 111 is 30cm, forming a high center and low periphery, which is conducive to the rapid collection of waste gas generated inside the double-layer cover pre-aeration tank 1. The height difference h1 between the center of the concave surface of the outer cover 110 and the center of the inner surface of the inner cover 111 is 50cm. Maintaining this height difference ensures that the hollow cover of the double-layer cover pre-aeration tank 1 has sufficient cavity to buffer the air pressure inside the sealed double-layer cover pre-aeration tank 1, preventing excessive changes in air pressure inside the double-layer cover pre-aeration tank 1 due to negative pressure suction after the first induced draft fan 176 is turned on, and ensuring that the drastic changes in dissolved oxygen concentration inside the double-layer cover pre-aeration tank 1 do not affect the pre-aeration treatment effect.

[0131] Figure 2 This is an enlarged schematic diagram of point A in the double-layer sealed pre-aeration tank 1 according to Embodiment 1 of the present invention. Figure 2As shown, the inner cover 111 and the outer cover 110 are integrally molded structures. The pre-aeration tank cover 11 and the pre-aeration tank body 10 are fixedly connected by a sealing gasket 12 and bolts 13, which can eliminate the leakage of waste gas from the pre-double-layer sealed pre-aeration tank 1. At the lowest point of the edge of the inner cover 111, circular drainage holes 112 with a diameter of 10mm are evenly distributed at intervals along the edge of the inner cover 111. Preferably, the spacing between adjacent drainage holes 112 is 5-30cm, more preferably 5-10cm. The cover material is made of corrosion-resistant material, preferably fiberglass. The drainage holes 112 are designed to recover the condensate in the hollow cover of the double-layer sealed pre-aeration tank 1 from the exhaust gas and return it to the double-layer sealed pre-aeration tank 1. This can reduce the pressure on the first induced draft fan 176 at the rear end, reduce the corrosion of the components of the first induced draft fan 176, extend the service life of the induced draft fan, reduce the failure rate of the fan, and at the same time reduce the material consumption of the next process.

[0132] Implementation Method 2

[0133] Figure 3 This is a schematic diagram of the double-layer sealed cover pre-aeration tank structure according to Embodiment 2 of the present invention. The main differences from Embodiment 1 are as follows:

[0134] like Figure 3 As shown, the pre-aeration tank cover 11 of the double-layer sealed pre-aeration tank 1 is fixedly connected to the pre-aeration tank body 10 by snap-fit. The inner cover 111 and the outer cover 110 are multiple integrally molded structures, that is, the individual cover plates composed of the inner cover 111 and the outer cover 110 are integrally molded sealing structures at the edge joints. Multiple individual cover plates are connected by edge overlap and sealing to form a complete pre-aeration tank cover 11. The sealing connection uses sealing gaskets and is fixedly connected by bolts or snap-fit. The sealing gasket is an adhesive material, preferably acrylic structural adhesive or two-component polyurethane structural adhesive, more preferably two-component polyurethane. In embodiment 2, the sealing connection between adjacent inner cover 111 and outer cover 110, between inner cover 111 and inner cover 111, and between outer cover 110 and outer cover 110 that make up the complete pre-aeration tank cover 11 is preferably fixedly connected by bolts or snap-fit ​​using sealing gaskets. Compared with embodiment 1, the design and manufacture of the pre-aeration tank cover 11 is more convenient because multiple individual cover plates are combined to form the pre-aeration tank cover 11, which is large in scale and size.

[0135] In embodiment 2, the vent 113 on the inner cover 111 has a circular cross-sectional shape. The inner cover 111 has one or more drainage holes at its lowest point relative to the bottom of the pre-aeration tank 10. These drainage holes 112 are rectangular, square, or irregular in shape, with a diameter of 10-50 mm. An elliptical vent 115 with a diameter of 200 mm is provided on the top of the outer cover 110, allowing gas to pass through the hollow cover. The vent 115 on the top of the outer cover 110 is offset from the vent 113 on or near the top of the inner cover 111 below it, with a horizontal distance of 1 m between the two holes. This prevents short-circuiting of airflow between the two covers, which would reduce the pre-aeration exhaust gas treatment effect.

[0136] In Embodiment 2, the height difference between the center of the concave surface of the inner cover 111 and the edge of the inner cover 111 is 50-100cm, preferably 50cm, forming a high center and low periphery, which is more conducive to the rapid collection of waste gas generated inside the pre-aeration tank. The height difference h1 between the center of the concave surface of the outer cover 110 and the center of the inner surface of the inner cover 111 is 80-100cm, preferably 80cm. Considering the actual scale of the pre-aeration tank on site, the single cover plate is designed according to the above-mentioned preferred dimensions in Embodiment 2. The actual pre-aeration effect is the best, that is, maintaining a height difference of 80cm can ensure that the hollow cover of the double-layer sealed pre-aeration tank 1 has sufficient cavity to buffer the air pressure inside the double-layer sealed pre-aeration tank 1. This prevents excessive changes in air pressure inside the double-layer sealed pre-aeration tank 1 due to negative pressure suction after the first induced draft fan 176 is turned on, which would cause drastic changes in dissolved oxygen concentration inside the pre-aeration tank and affect the pre-aeration treatment effect.

[0137] In embodiment 2, the inlet end of the first waste gas collection pipe 171 is fixedly connected to the end face of the protrusion 114 on the outer cover 110 by bolts or clips. A first hydrocyclone 173 and a third waste gas collection pipe 174 are sequentially connected between the second waste gas collection pipe 172 and the first induced draft fan 176. The outlet end of the first hydrocyclone 173 is connected to the inlet end of the third waste gas collection pipe 174. The liquid separated by the first hydrocyclone 173 returns to the double-covered pre-aeration tank 1 via the pre-aeration tank body 10 through the first hydrocyclone 173 and the first hydrocyclone return pipe 175 connected to the first hydrocyclone 173. The installation of the first hydrocyclone 173 on the waste gas collection device 17 can separate the liquid carried in the waste gas, reducing the pressure on the downstream first induced draft fan 176, mitigating corrosion of the fan components, extending the fan's lifespan, reducing the fan failure rate, and simultaneously reducing material consumption in the next process.

[0138] In embodiment 2, a first sludge return pipe 19 is also provided on the wall of the pre-aeration tank 10 to provide return sludge to the double-layer sealed pre-aeration tank 1. The return sludge is activated sludge from the sedimentation tank. In addition, the activated sludge in the double-layer sealed pre-aeration tank 1 is also returned for reuse to maintain a relatively stable activated sludge concentration in the double-layer sealed pre-aeration tank 1, while reducing the impact of high-concentration wastewater on the double-layer sealed pre-aeration tank 1, which is conducive to the stable operation of the double-layer sealed pre-aeration tank 1.

[0139] Implementation Method 3

[0140] Figure 4 This is a schematic diagram of the double-layer sealed cover pre-aeration tank structure according to Embodiment 3 of the present invention. It differs from Embodiment 2 mainly in the following two aspects:

[0141] First, the pre-aeration tank cover 11 of the double-layer sealed pre-aeration tank 1 has a different structure. In embodiment 3, the inner cover 111 of the pre-aeration tank cover 11 has a low center and a high edge, that is, the integrally formed single cover plate has a structure in which the inner cover 111 bulges outward. Therefore, multiple single cover plates are connected by overlapping and sealing at the edges to form a complete pre-aeration tank cover 11, forming a spindle-like shape with a relatively large hollow cavity. Ventilation holes 113 are opened on the edge of the inner cover 111, preferably symmetrically distributed on the edge of the inner cover 111, and the cross-sectional area of ​​the circular ventilation holes 113 is 20-300 cm². 2 A circular drain hole 112 with a diameter of 10mm is opened at the bottom center of the inner cover 111.

[0142] The advantage of this cover design is that it facilitates the collection and return of condensate in the hollow cover to the double-layer sealed pre-aeration tank 1, and the drainage hole 112 is easy to clean. In addition, for the cylindrical double-layer sealed pre-aeration tank 1, the ventilation hole 113 is set on the two symmetrical edges of the inner cover 111, and the staggered setting between the air outlet 115 at the top of the outer cover 110 and the ventilation hole 113 on the edge of the inner cover 111 below the air outlet 115 is easier to achieve. It is easier to achieve a horizontal distance of more than 1m between the two holes, which can effectively prevent the formation of airflow short-circuiting between the two covers and improve the pre-aeration exhaust gas treatment effect.

[0143] In addition, the height difference between the center of the concave surface of the inner cover 111 and the edge of the inner cover 111 is 50cm; the height difference between the center of the concave surface of the outer cover 110 and the center of the inner surface of the inner cover 111 is 100cm. Since the concave surface of the inner cover 111 faces the hollow cover space, it is easier to increase the distance between the center of the concave surface of the outer cover 110 and the center of the inner surface of the inner cover 111. For the pre-aeration tank with a very large circumferential diameter on site, it is easy to achieve sufficient cavity in the hollow cover without increasing the height of the outer cover 110. This can buffer the air pressure inside the double-layer sealed pre-aeration tank 1 and prevent excessive changes in air pressure in the pre-aeration tank caused by negative pressure suction after the first induced draft fan 176 is turned on, which would cause drastic changes in dissolved oxygen concentration in the pre-aeration tank and affect the pre-aeration treatment effect.

[0144] Secondly, the liquid separated by the first hydrocyclone 173 returns to the double-layer sealed pre-aeration tank 1 via the first hydrocyclone 173 through the pre-aeration tank body 10 and the pre-aeration tank cover 11 via the first hydrocyclone 173 and the first hydrocyclone return pipe 175. Adding the return via the pre-aeration tank cover 11 to the double-layer sealed pre-aeration tank 1 allows the condensate separated by the first hydrocyclone 173 to be used for cleaning and unblocking the drain hole 112. The first hydrocyclone 173 installed on the waste gas collection device 17 can separate the liquid carried in the waste gas, reducing the pressure on the downstream first induced draft fan 176, mitigating corrosion of the fan components, extending the fan's lifespan, reducing the fan failure rate, and simultaneously reducing material consumption in the next process.

[0145] Implementation methods 4-8

[0146] Figure 5-9 These are schematic diagrams of the double-layer sealed pre-aeration tank structures according to five embodiments of the present invention. Compared with embodiment 1, the main difference between these five embodiments lies in the different shapes of the inner sealing cover 111 and the outer sealing cover 110 of the double-layer sealed pre-aeration tank 1.

[0147] like Figure 5 As shown, in embodiment 4, the longitudinal cross-section of the inner cover 111 and the outer cover 110 of the double-layer sealed pre-aeration tank 1 is elliptical. The inner cover 111 and the outer cover 110 are both high in the center and low at the edge. The advantage of this pre-aeration tank cover 11 is that it is simple in design, easy to form in one piece, and easy to install.

[0148] like Figure 6As shown in Embodiment 5, the outer cover 110 of the double-layer sealed pre-aeration tank 1 has a triangular longitudinal cross-section, while the inner cover 111 is elliptical. The inner cover 111 is higher in the center and lower at the edges. This pre-aeration tank cover 11 adopts a multi-piece split structure design for the inner cover 111 and the outer cover 110, meaning that the inner cover 111 and the outer cover 110 are not integrally formed structures but are designed and manufactured separately. The joints between adjacent inner covers 111 and outer covers 110, between inner covers 111 and inner covers 111, and between outer covers 110 and outer covers 110 are sealed and connected, preferably using sealing gaskets and fixed with bolts or clips. During installation, the inner cover 111 is installed first, followed by the outer cover 110. The advantage of this pre-aeration tank cover 11 is that it is simple in design and easy to manufacture. The outer cover 110 and the inner cover 111 can be designed and processed separately, avoiding the need for mold making of the cover plate as a whole. Moreover, the outer cover 110 is designed in the form of a triangular canopy. When the pre-aeration tank body 10 is a cuboid, cube or irregular shape, it is easy to design without mold making and is also very convenient to install.

[0149] like Figure 7 As shown in Embodiment 6, the inner cover 111 of the double-layer sealed pre-aeration tank 1 is designed as a triangular canopy, and the outer cover 110 has an elliptical longitudinal cross-section. The lower end of the inner cover 111 also includes a support frame, which spans across the opening of the pre-aeration tank body 10 to support the pre-aeration tank cover 11. The advantages of this pre-aeration tank cover 11 are that it avoids the need for mold-making of the cover plate as a single piece; the triangular canopy design of the inner cover 111 facilitates production and installation; the support frame design is particularly practical for double-layer sealed pre-aeration tanks 1 with a large opening span of the pre-aeration tank body 10; and the design of the support frame allows for a wider range of material choices for the inner cover 111, extending to soft sealing materials such as transparent films, which are laid out with the support frame as a framework to form the inner cover 111.

[0150] In embodiment 7, the outer cover 110 of the double-layer sealed pre-aeration tank is hemispherical and the inner cover 111 is ellipsoidal, which is more suitable for pre-aeration tanks that require ultra-large pre-aeration tank treatment.

[0151] In embodiment 8, the inner cover 111 of the double-layer sealed pre-aeration tank has a concave elliptical longitudinal cross-section, and the outer cover 110 has an arc-shaped longitudinal cross-section. This design of the pre-aeration tank cover 11 is very suitable for pre-aeration tanks that require a larger capacity for the hollow cover, without the need to specifically increase the height of the outer cover 110. In the case of a large span, the outer cover 110 can be designed as an arc with a slight slope, which facilitates the collection of exhaust gas and saves on tank cover material.

[0152] Implementation Method 9

[0153] Figure 10The diagram shows a top view of the structure of two adjacent outer covers 110 of the double-layer sealed pre-aeration tank 1 according to Embodiment 9 of the present invention. Compared with Embodiment 2, in this embodiment, the pre-aeration tank body 10 is a cuboid, and the pre-aeration tank cover 11 is assembled from multiple single cover plates composed of inner covers 111 and outer covers 110. The joint 116 between the inner covers 111 and between the outer covers 110 and between the inner covers 111 and between the inner covers 111 and between the outer covers 110 are sealed and connected by overlapping edges. The two ends of the outer covers 110 and the inner covers 111 are sealed and connected by sealing gaskets, and are fixed by bolts or buckles. The sealing gaskets are two-component polyurethane adhesives.

[0154] For a relatively long pre-aeration tank 10, multiple first waste gas collection pipes 171 need to be designed and installed. For example, in embodiment 9, four first waste gas collection pipes 171 are installed and converged into a second waste gas collection pipe 172. If necessary, two or more first hydrocyclones 173 are also sequentially connected between the second waste gas collection pipe 172 and the first induced draft fan 176 to improve the gas-liquid separation performance of the first hydrocyclones 173. The separated liquid returns to the pre-aeration tank 10 through the first hydrocyclone return pipe 175 connected to the first hydrocyclone 173. Installing hydrocyclones can separate the liquid carried in the waste gas, reduce the pressure on the first induced draft fan 176, slow down the corrosion of the induced draft fan components, extend the service life of the induced draft fan, reduce the fan failure rate, and reduce material consumption in the next process. As needed, multiple first induced draft fans 176 can also be installed in series to improve the waste gas collection and treatment capacity.

[0155] Figure 11 This is a top view illustrating the single cover structure of the pre-aeration tank cover 11 of the double-layer sealed pre-aeration tank 1 according to Embodiment 9 of the present invention. In this embodiment, the circular drainage holes 112 of the cuboid double-layer sealed pre-aeration tank 1 are symmetrically distributed on both sides of the inner cover 111, and the vent hole 113 is located in the center of the inner cover 111. The air outlet 115 at the top of the outer cover 110 and the vent hole 113 at the center of the top of the inner cover 111 below the air outlet 115 are staggered, with a horizontal distance of 50cm between the two holes. This can prevent airflow short-circuiting between the two covers and reduce the pre-aeration exhaust gas treatment effect.

[0156] Implementation Method 10

[0157] Figure 12 A top view illustrating the double-layer sealed pre-aeration tank sealing structure of Embodiment 10 of the present invention. Figure 11Unlike embodiment 9, in this embodiment, the rectangular vent holes 113 of the cuboid double-layered pre-aeration tank 1 are symmetrically distributed on both sides of the inner cover 111, and the circular drain hole 112 is located in the center of the inner cover 111. The air outlet 115 at the top of the outer cover 110 and the drain hole 112 at the top center of the inner cover 111 below the air outlet 115 are staggered, and the horizontal distance between the two holes is 50cm, which can prevent the formation of airflow short-circuiting between the two covers and reduce the pre-aeration exhaust gas treatment effect.

[0158] Implementation Method 11

[0159] Figure 13 A top view illustrating the double-layer sealed pre-aeration tank sealing structure according to Embodiment 11 of the present invention. Figure 11 Unlike embodiment 9, in this embodiment, the double-layer sealed pre-aeration tank 1 is cylindrical, the inner cover 111 has a longitudinal cross-section with a small arc, for example, an arc of 3 degrees, the circular drain holes 112 are evenly distributed on both sides of the inner cover 111, the rectangular vent hole 113 is located in the center of the inner cover 111, the air outlet 115 at the top of the outer cover 110 and the vent hole 113 at the center of the top of the inner cover 111 below the air outlet 115 are staggered, the horizontal distance between the two holes is 50cm, which can prevent the formation of airflow short-circuiting between the two covers and reduce the pre-aeration exhaust gas treatment effect.

[0160] Implementation Method 12

[0161] Figure 14 A top view illustrating the double-layer sealed pre-aeration tank sealing structure according to Embodiment 12 of the present invention. Figure 11 Unlike embodiment 9, in this embodiment, the outer cover 110 and inner cover 111 of the cuboid double-layer sealed pre-aeration tank 1 are both elliptical in longitudinal cross-section. The top of the cover is high and the edges are low. The two ends of the outer cover 110 and inner cover 111 are sealed. Circular drainage holes 112 are evenly distributed on both sides of the inner cover 111. Rectangular vent holes 113 are located on the central strip of the inner cover 111. The air outlet 115 at the top of the outer cover 110 and the vent hole 113 at the center of the top of the inner cover 111 below the air outlet 115 are staggered. The horizontal distance between the two holes is 80cm, which can prevent the formation of airflow short-circuiting between the two covers and reduce the pre-aeration waste gas treatment effect.

[0162] Implementation Method 13

[0163] Figure 15 This is a schematic diagram of a biochemical waste gas treatment system and process flow according to one embodiment of the present invention. Figure 16 This is a schematic diagram of a spray aerobic tank structure in this embodiment. The following is in conjunction with... Figure 15 and Figure 16This invention discloses a biochemical waste gas treatment system and process flow.

[0164] like Figure 15 As shown, the present invention discloses a biochemical waste gas treatment system, comprising:

[0165] The double-layered sealed pre-aeration tank 1, the spray aerobic tank 2, and the exhaust gas emission device are connected in sequence. In this embodiment, the double-layered sealed pre-aeration tank 1 is according to Embodiment 2 of the present invention (i.e., Figure 3 The double-layer sealed pre-aeration tank 1 is a modified version of an existing cylindrical pre-aeration tank in a wastewater treatment plant, with the addition of a double-layer sealed pre-aeration tank cover 11. The outlet of the first induced draft fan 176 of the double-layer sealed pre-aeration tank 1 is connected to the spray aerobic tank 2, and the first gas collection pipe 281 of the exhaust gas emission device is connected to the exhaust hole 212 on the aerobic tank cover 21 of the spray aerobic tank 2.

[0166] Figure 16 It is based on the present invention Figure 15 A schematic diagram of a spray aerobic tank structure in one embodiment is shown. Figure 16 As shown, the spray aerobic tank 2 includes an aerobic tank body 20, an aerobic tank cover 21, a waste gas aeration device 22, a second wastewater inlet pipe 23, a second aeration device 24, a second wastewater outlet pipe 25, and a sludge spraying device 29. The aerobic tank cover 21 and the aerobic tank body 20 are fixedly connected at the edge contact points by bolts 215 or snap-fit ​​seals. The sealing material is a two-component polyurethane gasket 214. The sludge spraying device 29 is connected to the aerobic tank cover 21 for spraying activated sludge into the spray aerobic tank 2. In this embodiment, the aerobic tank body 20 is cylindrical in shape, and the aerobic tank cover 21 is assembled from multiple integrally molded structures. The longitudinal cross-section of the aerobic tank cover 21 is semi-elliptical. Adjacent aerobic tank covers 21 are connected by edge overlap and sealing gasket 214, and fixed by bolts 215 or snap-fit ​​seals. The sealing gasket 214 is an adhesive material, such as acrylic structural adhesive. For smaller spray aerobic tanks 2, the aerobic tank cover 21 can also be designed as a single-piece molded structure. The second aeration device 24 includes a second aeration main pipe 241, a second aeration branch pipe 242, and a second aeration head 243 connected in sequence. The aerobic tank cover 21 is made of a corrosion-resistant material, such as fiberglass.

[0167] See Figure 16The aerobic tank cover 21 has exhaust holes 212, and multiple holes can be provided as needed. They are usually located at the top of the aerobic tank cover 21, which facilitates the collection and passage of primary degradation waste gas inside the spray aerobic tank 2. The cross-section of the exhaust hole 212 can be designed as elliptical, circular, arc-shaped, rectangular, or irregular, preferably circular, with a diameter of 100-200mm. For ease of installation and sealing, the aerobic tank cover 21 has an outwardly protruding part 211 with openings at both ends at the exhaust hole 212. The first gas collecting pipe 281 is inserted into the outwardly protruding part 211 and fixed, and a sealed connection between the first gas collecting pipe 281 and the aerobic tank cover 21 is achieved by filling the connection with sealing material 213.

[0168] In embodiments of the present invention, such as Figure 16 The sludge spraying device 29 includes a spray liquid suction pipe 292, a sludge spraying pump 293, a sludge spraying main pipe 294, a sludge spraying branch pipe 295, and a sludge spraying head 299 connected in sequence. The inlet end of the spray liquid suction pipe 292 is submerged below the liquid surface in the aerobic spraying tank 2 and is arranged at the bottom of the aerobic spraying tank 20 near the tank wall, for example, near the wastewater outlet end at the bottom of the aerobic tank 20. The spray liquid suction pipe 292 is set on the tank wall of the aerobic tank 20. The sludge spraying branch pipe 295 passes through the aerobic tank cover 21 and enters the aerobic spraying tank 2. After entering the aerobic spraying tank 2, it is connected to the sludge spraying head 299 below the aerobic tank cover 21 through the sludge spraying branch pipe 298 to spray sludge to degrade aeration exhaust gas. To ensure sufficient contact between the sprayed sludge and the aeration exhaust gas in the tank, and to efficiently degrade the volatile organic compounds and odorous gases in the aeration exhaust gas, the sludge spray head 299 is an atomizing spray head for atomized spraying. The sludge spray branch pipes 298 are horizontally divided into multiple branches distributed below the aerobic tank cover 21, evenly distributed 1-3m above the liquid surface of the aerobic spray tank 2. Using atomizing spray heads to spray the sludge increases the contact area between the sprayed activated sludge and the exhaust gas. During the liquid-gas contact process, the atomized sludge further degrades harmful substances in the exhaust gas escaping from the liquid surface, achieving a better exhaust gas treatment effect.

[0169] See Figure 16To prevent debris such as garbage, leaves, and large particles from clogging the sludge spray head 299, a spray liquid filter 291, made of a cylindrical, spherical, or rectangular stainless steel cage with filter holes, is connected to the inlet end of the spray liquid suction pipe 292. The cage can also be wrapped with at least one layer of stainless steel mesh to improve the filtration effect of the sprayed sludge. Furthermore, to facilitate the detection, troubleshooting, and prevention of clogging of the sludge spray head 299, a branch valve 296, a pressure gauge 297, and a branch filter are sequentially installed on the sludge spray branch pipe 295 exposed above the aerobic tank cover 21. Both the pressure gauge 297 and the branch filter are detachably installed on the sludge spray branch pipe 295. The pressure gauge can also be replaced with a flow meter. Before spraying, the activated sludge is filtered through a two-stage system: a spray liquid filter 291 and a branch pipe filter. This filters out debris, leaves, large particles, and other blockages that would otherwise clog the sludge spraying branch pipe 295 and the sludge spray head 299, protecting the atomizing spray head and improving the system's stable operation.

[0170] See Figure 16 To ensure that the waste gas entering the aerobic spray tank 2 is fully degraded and to eliminate odors as much as possible, a waste gas aeration device 22 is installed to guide the waste gas entering the aerobic spray tank 2 to aerate the mud-water mixture W3. The waste gas aeration device 22 includes a waste gas aeration main pipe 221, a waste gas aeration branch pipe 222, and a waste gas aeration head 224 connected in sequence. The waste gas aeration main pipe 221 is installed on the tank wall of the aerobic tank body 20 and enters the aerobic spray tank 2, or it can be installed on the outer surface of the aerobic tank cover 21 and enters the aerobic spray tank 2 through the aerobic tank cover 21, extending towards the bottom of the aerobic tank body 20. The waste gas aeration branch pipe 222 and the waste gas aeration head 224 are evenly distributed 0.3-5.0m below the wastewater surface in the aerobic tank body 20, and waste gas is aerated into the aerobic tank body 20 through the waste gas aeration head 224. Installing gas dispersion devices such as exhaust gas aeration heads 224 is beneficial for the full dispersion of exhaust gas, thereby ensuring sufficient contact between the exhaust gas and the microbial community in the aerobic spray tank 2, and improving the exhaust gas treatment effect.

[0171] See Figure 15The exhaust gas emission device includes a waste gas collection device 28, an alkaline spray tower 3, a water spray box 4, a second induced draft fan 5, and an venting chimney 7, connected in sequence. The waste gas collection device 28 includes a first gas collection pipe 281, a second gas collection pipe 282, and a second cyclone separator 283, connected in sequence. The inlet end of the first gas collection pipe 281 is fixedly and sealed to the exhaust hole 212 on the aerobic tank cover 21. The outlet end of the second cyclone separator 283 is connected to a third gas collection pipe 284. The alkaline spray tower 3 includes a tower body, an alkaline spray tower liquid collection pipe 32 connected to the bottom of the tower, and an alkaline spray tower gas collection pipe 33 connected to the top of the tower. The third gas collection pipe 284 is connected to the alkaline spray tower liquid collection pipe 33. The bottom side of the spray tower 3 is connected; the water spray box 4 includes a box body, a water spray box liquid collection pipe 42 connected to the bottom of the box body, and a water spray box gas collection pipe 43 connected to the top of the box. An online exhaust gas pH detector is installed on the pipe of the water spray box gas collection pipe 43 leaving the water spray box 4. The alkaline spray tower gas collection pipe 33 is connected to the bottom side of the water spray box 4. The air inlet of the second induced draft fan 5 is connected to the water spray box gas collection pipe 43, and the air outlet is connected to the vent chimney 7 through the induced draft pipe 6.

[0172] The biochemical waste gas treatment process using embodiments of the present invention is as follows:

[0173] like Figure 15 As shown, wastewater or wastewater mixture W1 received from the plant area or external sources enters the double-layer sealed pre-aeration tank 1 through the first wastewater inlet pipe 15 on the tank wall of the pre-aeration tank 10. Air K enters the double-layer sealed pre-aeration tank 1 after passing through the first aeration main pipe 141 of the first aeration device 14, aerating the incoming wastewater or wastewater mixture W1. The tank wall of the pre-aeration tank 10 is also equipped with a first sludge return pipe 19, which provides return sludge to the double-layer sealed pre-aeration tank 1. The return sludge is activated sludge from the sedimentation tank. The addition of activated sludge performs preliminary degradation on the injected organic wastewater. The wastewater W2 treated by the double-layer sealed pre-aeration tank 1 enters the subsequent process for further treatment through the first wastewater outlet pipe 16. In addition, a portion of activated sludge is drawn from the first wastewater outlet pipe 16 of the double-layered sealed pre-aeration tank 1 through the sludge return pipe and returned to the double-layered sealed pre-aeration tank 1, flowing back to the vicinity of the inlet of the double-layered sealed pre-aeration tank 1 through the first wastewater inlet pipe 15. The reuse of activated sludge in the double-layered sealed pre-aeration tank 1 helps maintain a relatively stable activated sludge concentration, while also reducing the impact of high-concentration wastewater on the double-layered sealed pre-aeration tank 1, thus promoting stable aeration operation.

[0174] like Figure 15As shown, the first induced draft fan 176 extracts the waste gas containing organic volatiles generated by the aeration and natural volatilization of wastewater or wastewater mixture W1 in the double-layer sealed pre-aeration tank 1. The wind pressure of the first induced draft fan 176 is 3-60 kPa. The exhaust gas discharged from the first exhaust gas collection pipe 171, which is connected to the top of the double-layer sealed pre-aeration tank 1, enters the first hydrocyclone 173 through the second exhaust gas collection pipe 172. The liquid separated by the first hydrocyclone 173 returns to the double-layer sealed pre-aeration tank 1 from the pre-aeration tank body 10 through the first hydrocyclone return pipe 175. The liquid condensed inside the pre-aeration tank cover 11 returns to the double-layer sealed pre-aeration tank 1 through the circular drainage hole 112 with a diameter of 10-50mm opened on the edge of the inner cover 111. The exhaust gas separated by the first hydrocyclone 173 passes through the third exhaust gas collection pipe 174, the first induced draft fan 176, and the exhaust gas aeration device 22, and then enters the spray aerobic tank 2 through the aerobic tank cover 21 for exhaust gas aeration and activated sludge spraying, degrading the organic matter in the exhaust gas to form primary degradation exhaust gas.

[0175] See Figure 15 and Figure 16 The sludge-water mixture W3 from the sedimentation tank in the plant enters the spray aerobic tank 2 through the second wastewater inlet pipe 23 on the wall of the aerobic tank 20. Air K enters the spray aerobic tank 2 through the second aeration main pipe 241 of the second aeration device 24 and aerates the sludge-water mixture W3 by the second aeration head 243 installed on the second aeration branch pipe 242. The wastewater W4 after aeration treatment in the spray aerobic tank 2 enters the subsequent process for further treatment through the second wastewater outlet pipe 25. The second aeration device 24 aerates the spray aerobic tank 2. In the aerobic environment, the aerobic sludge degrades COD, nitrogen oxides, sulfides, etc. in the wastewater. During this process, the microorganisms absorb, decompose, and transform the odor substances in the aerated waste gas, thereby further degrading the harmful substances in the waste gas and improving the waste gas treatment effect. Aerobic tanks not only provide a continuous supply of microbial communities for wastewater and exhaust gas treatment, ensuring the continuity of exhaust gas treatment, but also eliminate the need for additional addition of new microbial communities and nutrients, resulting in low operating costs.

[0176] See Figure 16The sludge spraying device 29 sprays the activated sludge with the waste gas generated during aeration of the liquid surface above the liquid in the aerobic spraying tank 2, as well as the waste gas generated during aeration of the second aeration device 24 in the aerobic spraying tank 2. The resulting primary degradation waste gas enters the second gas collection pipe 282 and the second hydrocyclone 283, which are connected to the first gas collection pipe 281 of the waste gas collection device 28 connected to the exhaust hole 212 at the top of the aerobic tank cover 21 of the aerobic tank 2. After gas-liquid separation, the waste gas enters the subsequent process for waste gas emission treatment through the third gas collection pipe 284. The liquid separated by the second hydrocyclone 283 returns to the aerobic spraying tank 2 or the double-layer sealed pre-aeration tank 1 through the second hydrocyclone 283 connected to the second hydrocyclone 283. The second hydrocyclone 283 can be configured as one unit or multiple units connected in series or parallel, depending on the needs and waste gas treatment capacity.

[0177] See Figure 16 When the aerobic spray tank 2 is in operation, if during the inspection it is found that the pressure gauge 297 or flow meter installed on a certain sludge spray branch pipe 295 is abnormal, for example, the pressure gauge pressure is higher or the flow meter flow is lower compared with other sludge spray branch pipes 295 in the surrounding area, it indicates that the sludge spray head 299 installed in that line is blocked. At this time, the branch pipe valve 296 can be closed. The sludge spray head 299 and / or sludge spray branch pipe 298 can be removed through the connection between the sludge spray branch pipe 295 and the aerobic tank cover 21. The connection is sealed and fastened between the sludge spray branch pipe 295 and the aerobic tank cover 21 by end face sealing or threaded connection.

[0178] See Figure 15 The second induced draft fan 5 is started, and the air pressure is adjusted to 1.0-3.0 kPa. The primary degradation waste gas from the third gas collection pipe 284 enters from the bottom side of the alkaline spray tower 3. The alkaline solution 31 sprayed from the top of the alkaline spray tower 3 countercurrently sprays it to form secondary degradation waste gas. The secondary degradation waste gas is selected from the top or upper part of the alkaline spray tower 3 and enters the alkaline spray tower gas collection pipe 33. The liquid after alkaline spraying is discharged from the alkaline spray tower liquid collection pipe 32 at the bottom of the alkaline spray tower 3 for wastewater collection and treatment, or it is recirculated to the top of the alkaline spray tower 3 for continued alkaline spraying. Online pH detectors for waste gas are installed on the pipeline entering the alkaline spray tower 3 through the third gas collection pipe 284 and on the pipeline leaving the alkaline spray tower 3 through the alkaline spray tower gas collection pipe 33. The pH of the waste gas before entering the alkaline spray tower 3 is 5.5-6.0, and the pH after leaving the alkaline spray tower 3 is 6.8-7.2. On-site operation has proven that alkaline spraying removes acidic substances such as H2S and odor-causing substances that can be absorbed by alkaline solution from the primary degradation waste gas, thereby achieving further purification of the waste gas.

[0179] See Figure 15Water 41 sprayed from the top of the water spray tank 4 washes the secondary degradation waste gas from the alkaline spray tower gas collection pipe 33, adjusting the pH of the washing gas to neutral. The washing gas escapes from the top or upper part of the water spray tank 4 and enters the water spray tank gas collection pipe 43. The washed liquid is discharged from the water spray tank liquid collection pipe 42 at the bottom of the water spray tank 4 for wastewater collection and treatment. An online waste gas pH detector is installed on the pipe leaving the water spray tank 43 to ensure that the washing gas is discharged in a neutral state. The second induced draft fan 5 draws the washing gas from the water spray tank gas collection pipe 43 and sends it through the induced draft pipe 6 to the vent chimney 7 for discharge.

[0180] After the waste gas treatment system and process of this invention are applied, the odor concentration of the waste gas generated in the pre-aeration tank is 2000-2400 (dimensionless), which can completely eliminate fugitive emissions and greatly improve the on-site working environment. Finally, the odor concentration at the exhaust outlet of the chimney is reduced to 200-300 (dimensionless), and the odor treatment effect is obvious. Moreover, after the waste gas is sprayed with alkali and washed with water, the pH of the washing gas can be adjusted to neutral for emission, meeting the national waste gas emission standards.

[0181] Implementation Method 14

[0182] Figure 17 This is a schematic diagram of a biochemical waste gas treatment system and process flow according to another embodiment of the present invention. Figure 18-20 These are respectively based on the present invention Figure 17 A schematic diagram of a spray aerobic tank, a waste gas aeration device 22 and aeration pipeline, and a sludge spraying device and spraying pipeline is shown in the embodiment below. Figure 15 and Figure 16 The implementation methods of the process and equipment, combined with Figure 17-20 This invention introduces another biochemical waste gas treatment system and process flow.

[0183] like Figure 17 As shown, another biochemical waste gas treatment system disclosed in this invention includes: a double-layer sealed pre-aeration tank 1, a spray aerobic tank 2, and a waste gas emission device connected in sequence. The main differences between embodiment 14 and embodiment 13 are as follows:

[0184] First, the structure of the double-layer sealed pre-aeration tank 1 is different. In this embodiment, the double-layer sealed pre-aeration tank 1 is a modified version of an existing rectangular pre-aeration tank in a wastewater treatment plant, with the addition of a double-layer sealed pre-aeration tank cover 11. The structure of the double-layer sealed pre-aeration tank 1 is different from that of embodiment 9 of the present invention (i.e., Figure 10 The double-layer sealed pre-aeration tank 1 is basically the same as that in embodiment 9, except that the connection between the double-layer sealed pre-aeration tank 1 and the spray aerobic tank 2 is as follows: Figure 17As shown, the first hydrocyclone 173 of the double-layer sealed pre-aeration tank 1 is connected to the spray aerobic tank 2 via the first hydrocyclone return pipe 175, the first return pipe 26 connected to the aerobic tank cover 21, and / or the first return branch pipe 27 connected to the aerobic tank body 20.

[0185] Secondly, the structures of the two spray aerobic tanks are different. For example... Figure 18 As shown, the aerobic tank body 20 of the spray aerobic tank 2 is rectangular in shape, but can also be cubic or irregular in shape, depending on the actual needs. The longitudinal cross-section of the aerobic tank cover 21 is semi-circular, arc-shaped, or triangular. When the aerobic tank body 20 is wide and has a large span, a support frame is designed at the bottom of the aerobic tank cover 21. The support frame spans across the opening of the aerobic tank body 20 to support the aerobic tank cover 21. A viewing mirror is provided on the aerobic tank cover 21 to observe the sludge spraying inside the spray aerobic tank 2. During the design, viewing mirrors can be installed at intervals on the outer surface of the aerobic tank cover 21 above each sludge spraying branch pipe 298. The working status of the sludge spray head 299 can be directly observed through the viewing mirror, which helps to determine whether the sludge spray head 299 is blocked, facilitating maintenance or replacement, avoiding the need for periodic disassembly of the sludge spray head 299 for inspection, and improving work efficiency.

[0186] like Figure 19 As shown, in this embodiment, the waste gas aeration device 22 includes a waste gas aeration main pipe 220, a waste gas aeration main pipe 221, a waste gas aeration branch pipe 222, a waste gas aeration branch pipe 223, and a waste gas aeration head 224, which are connected in sequence. The waste gas aeration branch pipe 222 is installed on the outer surface of the aerobic tank cover 21 and enters the spray aerobic tank 2 through the aerobic tank cover 21, extending towards the bottom of the aerobic tank body 20. The waste gas aeration branch pipes 223 are symmetrically distributed in the aerobic tank body 20, evenly distributed 0.3-5.0m below the wastewater surface in the aerobic tank body 20. Waste gas is aerated into the aerobic tank body 20 through the waste gas aeration heads 224 installed on the waste gas aeration branch pipes 223. In this embodiment, the waste gas aeration branch pipes 222 can also be installed on the aerobic tank body 20. Figure 18 As shown, the exhaust gas aeration branch pipe 222 is installed on the tank wall of the aerobic tank 20 and enters the spray aerobic tank 2.

[0187] like Figure 20As shown, in this embodiment, since the spray aerobic tank 2 is rectangular with a length of 60-80 meters, in order to fully spray the sludge from the aeration exhaust gas generated in the spray aerobic tank 2, the sludge spray main pipe 294 is arranged and erected above the aerobic tank cover 21. Through three sludge spray branch pipes 295 arranged at intervals, it enters the spray aerobic tank 2 from the outer surface of the aerobic tank cover 21 in three sections. The sludge spray branch pipes 295 extend towards the bottom of the spray aerobic tank 2. At a distance of 1-3m above the liquid surface of the spray aerobic tank, they are connected to the parallel sludge spray branch pipes 298 that are evenly distributed below the aerobic tank cover 21. The sludge spray heads 299 are evenly distributed and installed on the sludge spray branch pipes 298. The sludge is sprayed through the atomized sludge spray heads 299. The atomized sludge further degrades the harmful substances in the aeration exhaust gas escaping from the liquid surface, achieving a better exhaust gas treatment effect. This multi-channel, uniformly arranged sludge spraying device and spraying pipeline structure can increase the liquid-gas contact area between waste gas and activated sludge, thereby improving the spraying treatment effect on waste gas degradation.

[0188] In addition, in order to ensure the rapid and effective extraction of the primary degradation waste gas formed after the sludge is sprayed, exhaust holes 212 are opened at intervals on the top of the aerobic tank cover 21, for example, at intervals of 10-20 meters. In this embodiment, a total of 3 circular exhaust holes 212 are opened, and 3 first gas collecting pipes 281 are correspondingly set and sealed to them. The second gas collecting pipe 282 collects the waste gas from the 3 first gas collecting pipes 281 and sends it into the second cyclone separator 283.

[0189] Third, the treatment methods for the liquid after alkaline spraying and the liquid after water washing are different. For example... Figure 17 As shown, the liquid after alkali spraying from the alkali spraying tower liquid collection pipe 32 at the bottom of the alkali spraying tower 3, and the liquid after washing from the water spraying tank liquid collection pipe 42 at the bottom of the water spraying tank 4, are collected in the waste liquid collection pipe 286 and then enter the second return pipe 287 to return to the spraying aerobic tank 2 and / or the double-layer sealed pre-aeration tank 1.

[0190] The biochemical waste gas treatment system and process of this invention can eliminate the fugitive emission of high-concentration (2000-2400, dimensionless) odorous waste gas generated in the pre-aeration tank, reducing the odor concentration at the final exhaust chimney to 200-300, demonstrating a significant odor treatment effect. This not only solves the technical shortcomings of simple alkaline scrubbing treatment of waste gas, which is ineffective, but also addresses the problems of high investment, high operating costs, and complex operation associated with traditional incineration, catalytic oxidation, and biological methods, thus reducing enterprise costs and mitigating secondary pollution from chemical use.

[0191] The above description is merely one embodiment of the present invention and is not intended to limit the invention. Those skilled in the art will recognize that the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A double-layer sealed pre-aeration tank, comprising a pre-aeration tank body and a pre-aeration tank cover, wherein the pre-aeration tank cover is a hollow cover formed by an inner cover and an outer cover, and the pre-aeration tank cover is sealed and fixedly connected to the pre-aeration tank body, characterized in that, The outer and inner covers are designed as arc-shaped structures with a high center and low edges in the longitudinal cross-section. The inner cover has at least one vent hole in the center to connect the hollow cover body with the pre-aeration tank body. The outer cover has at least one vent hole on the top to allow gas to pass through the hollow cover body. The inner cover has one or more drainage holes that connect to the pre-aeration tank at its lowest point relative to the bottom of the pre-aeration tank; the air outlet at the top of the outer cover is offset from the air vent and / or drainage hole on the inner cover; the height difference between the center of the concave surface of the inner cover and the edge of the inner cover is 30-100cm, and the height difference between the center of the concave surface of the outer cover and the center of the inner surface of the inner cover is 50-100cm. The pre-aeration tank is also equipped with a first sludge return pipe on its tank wall, which is used to provide return sludge to the double-layer sealed pre-aeration tank; the return sludge is distributed and returned to the inlet to outlet of the double-layer sealed pre-aeration tank through multiple points. A waste gas collection device is fixedly and sealed at the air outlet of the outer cover for collecting waste gas from the pre-aeration tank cover. The waste gas collection device includes a first waste gas collection pipe, a second waste gas collection pipe and a first exhaust fan connected in sequence. The air inlet end of the first waste gas collection pipe is sealed and connected to the air outlet of the outer cover of the pre-aeration tank. A first hydrocyclone and a third waste gas collection pipe are sequentially connected between the second waste gas collection pipe and the first induced draft fan. The outlet of the first hydrocyclone is connected to the inlet of the third waste gas collection pipe. The liquid separated by the first hydrocyclone is returned to the double-layer sealed pre-aeration tank through the first hydrocyclone return pipe connected to the first hydrocyclone. The pre-aeration tank is equipped with a first wastewater inlet pipe and a first wastewater outlet pipe on its tank wall; a first aeration device is installed inside the pre-aeration tank for aerating air into the double-layer sealed pre-aeration tank.

2. A biochemical waste gas treatment system, characterized in that, The system includes a double-layer sealed pre-aeration tank, an aerobic tank, and an exhaust gas emission device as described in claim 1, which are connected in sequence. The top of the cover of the aerobic tank is provided with at least one exhaust hole, and the exhaust gas emission device is installed at the exhaust hole.

3. The biochemical waste gas treatment system according to claim 2, characterized in that, The aerobic tank is a spray aerobic tank, including an aerobic tank body, an aerobic tank cover, and a sludge spraying device. The aerobic tank cover is sealed and fixedly connected to the aerobic tank body. The sludge spraying device is connected to the aerobic tank cover for spraying activated sludge into the spray aerobic tank. The sludge spraying device includes a spray liquid suction pipe, a sludge spraying pump, a sludge spraying main pipe, a sludge spraying branch pipe, and a sludge spraying head connected in sequence. The inlet end of the spray liquid suction pipe is submerged below the liquid surface in the aerobic spraying tank. The sludge spraying head is an atomizing spraying head. The sludge spraying branch pipe is detachably and sequentially equipped with a branch pipe valve, a pressure gauge or flow meter, and a branch pipe filter on the pipe exposed above the aerobic tank cover. The spray aerobic tank also includes an exhaust gas aeration device. The exhaust gas aeration device inputs exhaust gas received from the double-layer sealed pre-aeration tank into the spray aerobic tank through the first induced draft fan, and aeration is performed through exhaust gas aeration heads distributed 0.3 to 5.0 m below the wastewater surface in the aerobic tank. The wind pressure of the first induced draft fan is 3-60 kPa.

4. The biochemical waste gas treatment system according to claim 3, characterized in that, The exhaust gas emission device includes an exhaust gas collection device, an alkaline spray tower, a water spray box, a second induced draft fan, and an venting chimney connected in sequence. The air pressure of the second induced draft fan is 1.0-3.0 kPa.

5. A biochemical waste gas treatment process utilizing the biochemical waste gas treatment system according to any one of claims 2 to 4, characterized in that, Includes the following steps: Step S1: Inject activated sludge into the double-layer sealed pre-aeration tank, aerate the injected organic wastewater in the double-layer sealed pre-aeration tank, and perform preliminary degradation of the injected organic wastewater by the activated sludge. The activated sludge in the double-layer sealed pre-aeration tank is recycled; Step S2: The waste gas collection device is activated to collect the waste gas from the double-layer sealed pre-aeration tank through the air outlet at the top of the outer cover. The waste gas is then input into the sealed aerobic tank to react with the sludge in the aerobic tank to obtain primary degradation waste gas. The aerobic tank is a spray aerobic tank. The waste gas reacts with the sludge sprayed by the sludge spraying device in the spray aerobic tank to obtain primary degradation waste gas. The sludge is sprayed onto the waste gas entering the spray aerobic tank through the atomizing spray head of the sludge spraying device. Step S3: The primary degradation waste gas is collected and purified by the waste gas emission device before being discharged.

6. The biochemical waste gas treatment process according to claim 5, characterized in that, In step S2, the first induced draft fan of the waste gas collection device is started, and waste gas is aerated into the spray aerobic tank through the waste gas aeration device. The wind pressure of the first induced draft fan is 3-60 kPa. The waste gas aeration device includes a waste gas aeration main pipe, a waste gas aeration main pipe, a waste gas aeration branch pipe, a waste gas aeration branch pipe, and a waste gas aeration head connected in sequence. The waste gas aeration head is distributed 0.3-5.0 m below the wastewater surface in the aerobic tank, and waste gas is aerated into the aerobic tank through the waste gas aeration head.

7. The biochemical waste gas treatment process according to claim 5, characterized in that, In step S3, the exhaust gas emission device includes an exhaust gas collection device, an alkaline spray tower, a water spray box, a second induced draft fan, and an venting chimney connected in sequence. The primary degradation waste gas is drawn in by the second induced draft fan, first separated from the liquid carried by the waste gas collection device, and then enters the alkaline spray tower for alkaline washing and deacidification. Then it enters the water spray tank for water washing. The pH value in the waste gas is detected to adjust the alkaline spray volume and water washing volume. The pH of the washing gas is adjusted to neutral, and finally discharged through the venting chimney. The air pressure of the second induced draft fan is 1.0-3.0 kPa.

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