Plate production wastewater treatment system
Patent Information
- Application Number
- CN202522367964.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-07
- Publication Date
- 2026-09-22
- Estimated Expiration
- 2035-11-07
AI Technical Summary
[0002]板材生产过程中（如人造板、实木复合板等），需经过涂胶、热压、冷却、设备清洗等多道工序，会产生大量含油废水，其水质具有以下显著特征：油类成分复杂且含量高：废水中油类包括涂胶工序残留的矿物油（如润滑油、脱模油）、木材处理过程中溶出的动植物油，以及因搅拌、高压作用形成的乳化油，实测油含量通常为80-200mg/L，部分工况下可达300mg/L以上，且乳化油占比超40%，常规静置隔油难以有效分离；有机污染物种类多：废水中除油类外，还含有胶黏剂残留的甲醛、苯酚，以及木材水解产生的纤维素、半纤维素降解产物，导致COD（化学需氧量）浓度维持在800-1500mg/L，且部分有机污染物（如酚类）具有生物毒性，易抑制微生物活性；水质水量波动大：板材生产为间歇性作业，废水排放呈现“脉冲式”特征——生产高峰期（如热压工序集中时段）废水排放量可达10-15m3/h，而停产时段排放量不足1m3/h，同时油含量、COD浓度波动幅度超50%，对处理系统的抗冲击能力要求极高
（1）通过“刮油机+隔油罐+废油收集罐”的组合，浮油去除率达95%以上，乳化油经后续生化处理间接降解，进水油含量从80-200mg/L降至5-10mg/L，彻底解决油类对微生物的抑制问题；采用“火山岩琉璃球填料+精准微曝气”的固定床工艺，COD去除负荷从0.2-0.3kgCOD/m3d提升至0.5-0.8kgCOD/m3
d，提升幅度超50%；同时有机氮释放率从不足40%提升至65%-75%，为后续脱氮奠定基础。
Smart Images
Figure CN224783975U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of wastewater treatment technology, specifically a wastewater treatment system for board production. Background Technology
[0002] In the production of wood-based panels (such as engineered wood panels and solid wood composite panels), multiple processes are required, including gluing, hot pressing, cooling, and equipment cleaning. This generates a large amount of oily wastewater, which exhibits the following significant characteristics: Complex and high oil content: The oil in the wastewater includes residual mineral oil (such as lubricating oil and release oil) from the gluing process, animal and vegetable oils dissolved during wood processing, and emulsified oil formed due to stirring and high pressure. Actual oil content is typically 80-200 mg / L, and can reach over 300 mg / L under certain conditions. Furthermore, emulsified oil accounts for over 40% of the total oil content. Oil separation is difficult; there are many types of organic pollutants: in addition to oil, the wastewater also contains formaldehyde and phenol from adhesive residues, as well as cellulose and hemicellulose degradation products from wood hydrolysis, resulting in COD (chemical oxygen demand) concentrations remaining at 800-1500 mg / L. Furthermore, some organic pollutants (such as phenols) are biotoxic and easily inhibit microbial activity; water quality and quantity fluctuate greatly: board production is an intermittent operation, and wastewater discharge exhibits a "pulse-like" characteristic—during peak production periods (such as concentrated hot-pressing processes), wastewater discharge can reach 10-15 mg / L. 3 / h, while emissions during shutdown periods are less than 1m³. 3 The oil content and COD concentration fluctuate by more than 50% per hour, which places extremely high demands on the treatment system's resistance to shocks.
[0003] The existing wastewater treatment technology for wood-based panels in the workshop has the following core defects: Most systems use simple static oil separators without oil skimming devices or demulsification measures, resulting in ineffective separation of emulsified oil. This leads to an oil content exceeding 50 mg / L in the influent to the subsequent biological unit, causing microbial cell membranes to be coated with oil and reducing activity by 30%-50%. Traditional hydrolysis acidification tanks use empty tanks or simple packing materials without precise aeration control, resulting in large fluctuations in DO (dissolved oxygen) concentration (0.1-1.0 mg / L), an organic nitrogen (such as nitrogen-containing compounds in adhesives) release rate of less than 40%, and a COD removal load of only 0.2-0.3 kgCOD / m³. 3 d. The system cannot meet subsequent treatment requirements; some systems do not have separate aerobic decarbonization tanks, or the oxygen utilization rate of the aeration devices is low, resulting in a COD removal rate of only 50%-60% in the aerobic section, with effluent COD exceeding 100mg / L, which fails to meet the Class I standard (COD≤60mg / L) of the "Integrated Wastewater Discharge Standard" (GB8978-1996); the return pipelines of the sludge sedimentation tank, hydrolysis acidification tank, and aerobic decarbonization tank are not equipped with precise flow control, resulting in large fluctuations in the sludge return ratio (100%-300%), leading to unstable sludge concentration in the biological unit (2000-6000mg / L) and treatment efficiency fluctuations exceeding 20%; at the same time, the remaining sludge is discharged directly without filtration treatment, which can easily cause secondary pollution.
[0004] To address the aforementioned issues, there is an urgent need to design a wastewater treatment system for board production that can efficiently separate oils, increase the biochemical treatment load, stably remove COD, and has strong impact resistance, ensuring that the effluent meets discharge standards. Utility Model Content
[0005] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a wastewater treatment system for board production. Through the combination of "oil skimmer + oil separator + waste oil collection tank", the floating oil removal rate reaches more than 95%. The emulsified oil is indirectly degraded through subsequent biochemical treatment, and the oil content of the influent is reduced from 80-200mg / L to 5-10mg / L, which completely solves the problem of oil inhibiting microorganisms.
[0006] This utility model is achieved using the following technical solution: The wastewater treatment system for wood-based panel production includes a water storage tank, an oil separator, a booster tank, an equalization tank, a hydrolysis acidification tank, a sludge sedimentation tank, an aerobic decarbonization tank, a secondary sedimentation tank, and a clear water tank, all connected sequentially by pipelines. The oil separator is equipped with an oil skimming device; the equalization tank, hydrolysis acidification tank, and aerobic decarbonization tank are each equipped with an aeration device; and the secondary sedimentation tank is equipped with a flocculant dosing device. The outlet of the water storage tank is connected to the inlet of the oil separator via a pipeline, and the outlet of the oil separator is connected to the booster tank via a pipeline. The inlet of the booster tank is connected to the outlet of the booster tank, which is connected to the inlet of the equalization tank via a pipe. The outlet of the equalization tank is connected to the inlet of the hydrolysis acidification tank via a pipe. The outlet of the hydrolysis acidification tank is connected to the inlet of the sludge sedimentation tank via a pipe. The outlet of the sludge sedimentation tank is connected to the inlet of the aerobic decarbonization tank via a pipe. The outlet of the aerobic decarbonization tank is connected to the inlet of the secondary sedimentation tank via a pipe. The outlet of the secondary sedimentation tank is connected to the inlet of the clear water tank via a pipe.
[0007] The oil skimming device is an oil skimmer, which is horizontally installed in the oil separator near the liquid surface. The oil outlet of the oil skimmer is connected to the oil inlet of the oil separator through an oil outlet pipe, and the oil outlet of the oil separator is connected to the oil inlet of the waste oil collection tank through a pipe.
[0008] The flocculant dosing device includes a flocculant dosing tank and a metering pump; the outlet of the flocculant dosing tank is connected to the inlet of the metering pump through a pipeline, and the outlet of the metering pump extends into the secondary sedimentation tank through a pipeline, with the pipeline outlet located 0.3-0.5m below the liquid surface of the secondary sedimentation tank.
[0009] The inlet pipe of the grease trap is equipped with a booster pump, a flow meter and a regulating valve in sequence along the water flow direction; level gauges are installed at the bottom of both the water storage tank and the regulating tank, and the detection end of the level gauge is 0.1-0.2m higher than the bottom of the tank; the grease trap is equipped with an oil scraping device, which uses a chain drive to push the rubber scraper to scrape off the residual grease in the production of the board, followed by three-stage sedimentation and oil separation.
[0010] The aeration devices for the equalization tank and the hydrolysis acidification tank are all perforated aeration pipes, while the aeration devices for the aerobic decarbonization tank are microporous aeration heads. The air inlet ends of both the perforated aeration pipes and the microporous aeration heads are connected to the air outlet end of the Roots blower through pipelines.
[0011] Above the perforated aeration pipe in the hydrolysis acidification tank, there is a fiberglass grating support. Volcanic rock glass ball packing is evenly laid on the packing support, and the packing volume accounts for 35% of the effective volume of the hydrolysis acidification tank.
[0012] A booster pump, a flow meter, and a regulating valve are sequentially installed on the inlet pipe of the hydrolysis acidification tank along the water flow direction; An internal reflux pump is installed inside the sludge settling tank. The inlet of the internal reflux pump is connected to the bottom of the sludge settling tank, and the outlet is connected to the top of the sludge settling tank through a pipe to form an internal circulation. The sludge settling tank is connected to the hydrolysis acidification tank through a sludge return pipe. A sludge return pump, a flow meter and a regulating valve are installed sequentially along the sludge flow direction on the sludge return pipe. The inlet of the sludge return pump is connected to the bottom of the sludge settling tank, and the outlet is connected to the middle of the hydrolysis acidification tank through the sludge return pipe.
[0013] A sludge scraper is installed in the secondary sedimentation tank, with the scraper blades positioned close to the bottom of the tank. The secondary sedimentation tank is connected to the hydrolysis acidification tank through the first sludge return pipe, to the aerobic decarbonization tank through the second sludge return pipe, and to the plate and frame filter press through the remaining sludge pipe. The first sludge return pipe, the second sludge return pipe, and the remaining sludge pipe are all equipped with sludge return pumps, flow meters, and regulating valves in sequence along the sludge flow direction; the filtrate outlet of the plate and frame filter press is connected to the inlet of the filtrate collection tank through a pipe, and the outlet of the filtrate collection tank is connected to the inlet of the regulating tank through a pipe.
[0014] The tops of the equalization tank, hydrolysis acidification tank, sludge sedimentation tank, and aerobic decarbonization tank are all sealed and covered with fiberglass gas collection hoods. The edges of the fiberglass gas collection hoods are sealed to the flanges at the top of the tanks, and exhaust gas outlet pipes are installed at the top of the gas collection hoods.
[0015] The water storage tank is used to temporarily store wastewater discharged from various processes in the production of wood panels, buffering fluctuations in water volume; the effective volume of the tank is 15-20m³. 3 The structure is made of reinforced concrete with anti-corrosion treatment on the inner walls. A level gauge is installed at the bottom to monitor the water level in real time and prevent overflow. The oil-water separator achieves oil-water separation, and the effective volume of the tank is 8-12m³. 3 The hydraulic retention time (HRT) is 1.5-2 hours; an internal horizontal oil skimmer (model: GY-5, skimming speed 0.5-1 m / min) is installed to remove floating oil from the liquid surface; booster pumps (flow rate: 5-10 m³ / min) are sequentially installed along the water flow direction on the inlet pipe. 3 / h), flow meter (range: 0-20m) 3 The system includes a regulating valve ( / h) to control the inlet water flow rate; the oil outlet of the oil skimmer is connected to an oil separator (volume: 5m³) via an oil outlet pipe. 3 The oil separator connects to the waste oil collection tank (volume: 10m³) via gravity flow, allowing waste oil to be transferred from the oil separator to the waste oil collection tank. 3 This process enables waste oil recovery. The lifting tank is used to lift the wastewater after oil separation to the equalization tank; the effective volume of the tank is 5-8 m³. 3 It has a built-in booster pump (head: 15-20m) to ensure stable wastewater delivery.
[0016] The equalization tank balances water quality and quantity, with an effective volume of 20-25 m³. 3 HRT is 4-6 hours; perforated aeration pipes (hole diameter: 5mm, spacing: 200mm) are laid at the bottom, and air is supplied by a Roots blower (air volume: 3-5m³ / h). 3 Aeration and mixing are carried out at a rate of 5-8 min, with DO controlled at 1.0-2.0 mg / L to prevent wastewater stratification; an internal level gauge, combined with a booster pump, flow meter, and regulating valve on the inlet pipe, enables precise control of the inlet flow rate (5-8 m). 3 / h). The hydrolysis acidification tank improves COD removal rate and promotes organic nitrogen release, with an effective volume of 18-22m³. 3 The HRT (Heat Retention Time) is 8-10 hours. A fixed-bed process is adopted, with perforated aeration pipes laid at the bottom and a fiberglass grating support above. Volcanic rock glass spheres (particle size: 30-50mm, filling rate: 35%) are evenly laid on the support. Micro-aeration is achieved using a Roots blower, and DO (Dissolved Oxygen) is strictly controlled at 0.2-0.5 mg / L. A lift pump, flow meter, and regulating valve are installed on the inlet pipe to control the inlet flow rate and match it with the hydrolysis acidification reaction. A sludge sedimentation tank separates sludge from wastewater and replenishes the sludge in the hydrolysis acidification tank; the effective volume is 10-15 m³. 3 HRT is 2-3 hours; built-in internal reflux pump (flow rate: 10-15 m³ / h) 3The system forms an internal circulation (recirculation ratio 200%-300%), improving the contact efficiency between microorganisms and wastewater; it is connected to the hydrolysis acidification tank through a sludge return pipe, and a sludge return pump (flow rate: 3-5 m³ / h) is installed on the return pipe. 3 / h), flow meter and regulating valve, sludge return ratio controlled at 50%-80%, maintain sludge concentration in hydrolysis acidification tank (3000-4000mg / L).
[0017] Aerobic decarbonation tank for deep COD removal, with an effective volume of 25-30m³. 3 The HRT is 10-12 hours; microporous aeration heads (pore size: 10-20 μm, oxygen utilization rate 25%-30%) are evenly arranged at the bottom, and the air is supplied by a Roots blower (air volume: 8-10 m³ / h). 3 Aeration is carried out at a rate of 1000 mg / min, with DO controlled at 2.0-3.0 mg / L; aerobic decarbonation bacteria (such as Pseudomonas and Bacillus) are cultivated, and the sludge concentration is maintained at 4000-5000 mg / L to ensure a COD removal rate of over 70%. A secondary sedimentation tank is used for sludge settling and recirculation, with an effective volume of 15-20 m³. 3 HRT is 3-4 hours; built-in sludge scraper (model: GN-10, scraping speed 0.3-0.5 m / min) scrapes sludge close to the bottom of the pool; equipped with flocculant dosing device (flocculation dosing tank volume: 2 m³ / min) 3 Metering pump flow rate: 0.1-0.3 m³ / h 3 / h), add polyaluminum chloride (PAC) flocculant (dosage: 50-80mg / L) to improve sludge settling efficiency; connect to the hydrolysis acidification tank (recirculation ratio 30%-50%), the aerobic decarbonization tank (recirculation ratio 100%-150%), and the plate and frame filter press (model: XMYZ-200 / 1250-UB) through three sludge pipelines respectively. After the remaining sludge is filtered, the moisture content is reduced to 60%-70%, and the filtrate is introduced into the filtrate collection tank (volume: 5m³). 3 The water is then returned to the equalization tank. The clear water tank stores the compliant effluent, with an effective volume of 15-20 m³. 3 The tanks are equipped with online monitoring instruments (monitoring COD, oil content, and pH) to ensure that the effluent meets the Class I standard of the "Integrated Wastewater Discharge Standard" (GB8978-1996) before being discharged. Furthermore, the tops of the equalization tank, hydrolysis acidification tank, sludge sedimentation tank, and aerobic decarbonization tank are all sealed with fiberglass gas collection hoods (thickness: 5mm, temperature range: -20℃-80℃). Each gas collection hood has a 150mm diameter exhaust pipe at its top, which can be connected to a waste gas treatment device (such as an activated carbon adsorption tower) to prevent waste gas diffusion.
[0018] Compared with the prior art, the beneficial effects of this utility model are: (1) By combining "oil skimmer + oil separator + waste oil collection tank", the floating oil removal rate reaches over 95%, and the emulsified oil is indirectly degraded through subsequent biochemical treatment, reducing the oil content in the influent from 80-200 mg / L to 5-10 mg / L, thus completely solving the problem of oil inhibiting microorganisms; the fixed-bed process using "volcanic rock glass ball packing + precise micro-aeration" reduces the COD removal load from 0.2-0.3 kgCOD / m³. 3 d increased to 0.5-0.8 kg COD / m 3 d, the increase exceeded 50%; at the same time, the organic nitrogen release rate increased from less than 40% to 65%-75%, laying the foundation for subsequent denitrification.
[0019] (2) The oxygen utilization rate of the microporous aeration head reaches 25%-30%. Combined with the exclusive aerobic decarbonization bacteria, the COD removal rate of the aerobic section is stable at over 70%. The total COD removal rate of the system is increased from 60%-70% of the existing technology to 85%-90%. The COD of the effluent is stably controlled at 40-60 mg / L, meeting the first-class discharge standard. Through "internal recirculation + precise sludge recirculation ratio control", the sludge concentration in the hydrolysis acidification tank is stable at 3000-4000 mg / L, and the sludge concentration in the aerobic decarbonization tank is stable at 4000-5000 mg / L. The fluctuation range of treatment efficiency is reduced from 20% to less than 5%. The moisture content of the remaining sludge is reduced to 60%-70% after plate and frame filter press. The filtrate is recirculated and there is no secondary pollution. The fiberglass gas collection hood achieves 100% collection of waste gas, avoiding air pollution. The large volume and aeration stirring design of the equalization tank can buffer more than 50% of water quality and quantity fluctuations, adapting to the intermittent discharge characteristics of board production. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the wastewater treatment system for sheet metal production according to this utility model; In the diagram: 1. Water storage tank; 2. Oil separator; 3. Lifting tank; 4. Equalization tank; 5. Hydrolysis acidification tank; 6. Sludge sedimentation tank; 7. Aerobic decarbonization tank; 8. Secondary sedimentation tank; 9. Clear water tank; 10. Lifting pump; 11. Flow meter; 12. Control valve; 13. Internal return pump; 14. Sludge return pump; 15. Oil skimmer; 16. Level gauge; 17. Roots blower; 18. Microporous aeration head; 19. Flocculation dosing tank; 20. Metering pump; 21. Plate and frame filter press; 22. Filtrate collection tank; 23. Oil separator; 24. Waste oil collection tank; 25. Perforated aeration pipe. Detailed Implementation
[0021] To make the objectives and technical solutions of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings.
[0022] Example 1 like Figure 1As shown, the wastewater treatment system for board production includes a water storage tank 1, an oil separator 2, a booster tank 3, an equalization tank 4, a hydrolysis acidification tank 5, a sludge sedimentation tank 6, an aerobic decarbonization tank 7, a secondary sedimentation tank 8, and a clear water tank 9, all connected sequentially by pipelines. The oil separator 2 is equipped with an oil skimming device; the equalization tank 4, hydrolysis acidification tank 5, and aerobic decarbonization tank 7 are each equipped with an aeration device; and the secondary sedimentation tank 8 is equipped with a flocculant dosing device. The outlet of the water storage tank 1 is connected to the inlet of the oil separator 2 via a pipeline, and the outlet of the oil separator 2 is connected to the outlet of the oil separator 2 via a pipeline. The water inlet of the lifting tank 3 is connected to the water inlet of the equalization tank 4 via a pipe. The water outlet of the equalization tank 4 is connected to the water inlet of the hydrolysis acidification tank 5 via a pipe. The water outlet of the hydrolysis acidification tank 5 is connected to the water inlet of the sludge sedimentation tank 6 via a pipe. The water outlet of the sludge sedimentation tank 6 is connected to the water inlet of the aerobic decarbonization tank 7 via a pipe. The water outlet of the aerobic decarbonization tank 7 is connected to the water inlet of the secondary sedimentation tank 8 via a pipe. The water outlet of the secondary sedimentation tank 8 is connected to the water inlet of the clear water tank 9 via a pipe. The oil skimmer 15 is horizontally installed in the oil separator 2 near the liquid surface. The oil outlet of the oil skimmer 15 is connected to the oil inlet of the oil separator 23 via an oil outlet pipe. The oil outlet of the oil separator 23 is connected to the oil inlet of the waste oil collection tank 24 via a pipe. The flocculant dosing device includes a flocculant dosing tank 19 and a metering pump 20. The outlet of the flocculant dosing tank 19 is connected to the inlet of the metering pump 20 via a pipe. The outlet of the metering pump 20 extends into the secondary sedimentation tank 8 via a pipe, and the pipe outlet is located 0.3-0.5m below the liquid surface in the secondary sedimentation tank 8. A booster pump 10, a flow meter 11, and a regulating valve 12 are sequentially installed along the water flow direction on the inlet pipe of the oil separator 2. Level gauges 16 are installed at the bottom of both the water storage tank 1 and the regulating tank 4, with the detection end of the level gauge 16 0.2m above the bottom of the tank. An oil scraping device is installed in the oil separator 2, using a chain drive to push a rubber scraper to scrape off residual grease from the board production process, followed by three-stage sedimentation and oil separation. The aeration devices for the equalization tank 4 and the hydrolysis acidification tank 5 are both perforated aeration pipes 25, and the aeration device for the aerobic decarbonization tank 7 is a microporous aeration head 18. The air inlet ends of the perforated aeration pipes 25 and the microporous aeration heads 18 are connected to the air outlet end of the Roots blower 17 through pipes. A fiberglass grating support is installed above the perforated aeration pipes 25 in the hydrolysis acidification tank 5. Volcanic rock glass ball packing is evenly laid on the packing support, and the packing volume accounts for 35% of the effective volume of the hydrolysis acidification tank 5.A booster pump 10, a flow meter 11, and a regulating valve 12 are sequentially installed on the inlet pipe of the hydrolysis acidification tank 5 along the water flow direction. An internal return pump 13 is installed in the sludge sedimentation tank 6. The inlet end of the internal return pump 13 is connected to the bottom of the sludge sedimentation tank 6, and the outlet end is connected to the upper part of the sludge sedimentation tank 6 through a pipe to form an internal circulation. The sludge sedimentation tank 6 is connected to the hydrolysis acidification tank 5 through a sludge return pipe. A sludge return pump 14, a flow meter 11, and a regulating valve 12 are sequentially installed on the sludge return pipe along the sludge flow direction. The inlet end of the sludge return pump 14 is connected to the bottom of the sludge sedimentation tank 6, and the outlet end is connected to the middle part of the hydrolysis acidification tank 5 through the sludge return pipe. A sludge scraper is installed inside the secondary sedimentation tank 8, with the scraper blades positioned close to the bottom of the tank. The secondary sedimentation tank 8 is connected to the hydrolysis acidification tank 5 via a first sludge return pipe, to the aerobic decarbonization tank 7 via a second sludge return pipe, and to the plate and frame filter press 21 via a residual sludge pipe. A sludge return pump 14, a flow meter 11, and a regulating valve 12 are sequentially installed along the sludge flow direction on the first sludge return pipe, the second sludge return pipe, and the residual sludge pipe. The filtrate outlet of the plate and frame filter press 21 is connected to the inlet of the filtrate collection tank 22 via a pipe, and the outlet of the filtrate collection tank 22 is connected to the inlet of the equalization tank 4 via a pipe. The tops of the equalization tank 4, the hydrolysis acidification tank 5, the sludge sedimentation tank 6, and the aerobic decarbonization tank 7 are all sealed with fiberglass gas collection hoods. The edges of the fiberglass gas collection hoods are sealed to the flanges at the top of the tanks, and exhaust gas outlet pipes are installed at the top of the gas collection hoods.
[0023] The above-mentioned wastewater treatment system for board production includes the following steps during operation: Operating conditions of a certain artificial board factory (daily wastewater discharge 120-150m³) 3 The influent oil content is 120-180 mg / L, COD is 1000-1300 mg / L, and ammonia nitrogen is 30-40 mg / L, which must meet the Class I standard of the "Integrated Wastewater Discharge Standard". The normal treatment process of the system is as follows: The workshop wastewater first flows by gravity into storage tank 1, where the liquid level reaches 70% (14m). 3 When the concentration of grease is below 30% (6m), it is directed to oil separator 2. 3 Then close the valve to prevent the pump from running dry, and lift pump 10 in oil separator 2 at 8m. 3 Water is supplied at a rate of / h (hydraulic retention time 1.5-2h), and the oil skimmer 15 (0.8m / min) scrapes the floating oil to the oil separator 23. The oil separator 23 is filled to 80% (4m). 3 Afterwards, the waste oil is directed to the waste oil collection tank 24. The wastewater, after oil-water separation (oil content reduced to 10-15 mg / L), flows by gravity into the lifting tank 3, and is then sent to the equalization tank 4 by the lifting pump 10. The equalization tank 4 then starts the Roots blower 17 (4m). 3 / min), through perforated aeration pipe 25 aeration (DO 1.0-2.0 mg / L), at 6m 3 / h of incoming water (hydraulic retention time 4-6h) to equalize water quality; COD and pH are tested every 2h; if they exceed the standard, acid or alkali is added; water level reaches 60% (13.2m). 3 Then, it is pumped to the hydrolysis acidification tank 5 via the booster pump 10; the hydrolysis acidification tank 5 is filled with 6m³ of water. 3 The wastewater flows in at a rate of / h (hydraulic retention time 8-10h), and is micro-aerated through perforated aeration pipes (DO 0.2-0.5mg / L). Microorganisms attached to the volcanic rock packing decompose organic nitrogen (release rate 65%-75%), reducing COD to 500-700mg / L. The wastewater then flows by gravity into sludge sedimentation tank 6, where it remains for 2-3 hours before being pumped back to the sludge via internal return pump 13 (12m). 3 / h) Internal reflux enhances the reaction, and the sludge is pumped through sludge return pump 14 at a rate of 4m 3 The wastewater is returned to the hydrolysis acidification tank 5 (maintaining a sludge concentration of 3200-3800 mg / L) at a rate of 1 h / h. The supernatant enters the aerobic decarbonation tank 7, where it is aerated through microporous aerators 18 (DO 2.0-3.0 mg / L). The hydraulic retention time is 10-12 h, reducing the COD to 80-120 mg / L. The wastewater then flows by gravity into the secondary sedimentation tank 8. In the secondary sedimentation tank 8, PAC (60 mg / L) is added through the flocculation dosing tank 19 and metering pump 20. The sludge is then scraped and transported in three separate streams via the sludge return pump 14: 2 m 3 / h return hydrolysis acidification tank 5, 8m 3 / h return to aerobic decarbonization tank 7, 1m 3 The sludge is fed to the plate and frame filter press 21 at a rate of 60%-70% (after filtration, the sludge moisture content is 60%-70%). The filtrate is returned to the equalization tank 4 through a pipeline, and the supernatant enters the clear water tank 9. The clear water tank 9 is monitored by an online monitoring instrument. If the sludge meets the standards (COD 45-58 mg / L, oil content 3-8 mg / L, ammonia nitrogen 10-14 mg / L), it is discharged. If the sludge does not meet the standards, it is returned to the equalization tank 4. At the same time, the FRP gas collection hoods at the top of the equalization tank 4, hydrolysis acidification tank 5, sludge sedimentation tank 6, and aerobic decarbonization tank 7 collect the waste gas. The waste gas is purified by the activated carbon adsorption tower before being discharged. The entire treatment process takes 31-41 hours and can achieve stable compliance with wastewater standards.
[0024] After 30 days of continuous operation, the monitoring data is as follows:
Claims
1. A wastewater treatment system for board manufacturing, characterized in that, The system includes a water storage tank (1), an oil separator (2), a lift tank (3), an equalization tank (4), a hydrolysis acidification tank (5), a sludge sedimentation tank (6), an aerobic decarbonization tank (7), a secondary sedimentation tank (8), and a clear water tank (9), all connected sequentially by pipes. The oil separator (2) is equipped with an oil skimming device. The equalization tank (4), hydrolysis acidification tank (5), and aerobic decarbonization tank (7) are each equipped with an aeration device. The secondary sedimentation tank (8) is equipped with a flocculant dosing device. The outlet of the water storage tank (1) is connected to the inlet of the oil separator (2) via a pipe, and the outlet of the oil separator (2) is connected to the lift tank via a pipe. The inlet end of the pool (3) is connected, the outlet end of the lifting pool (3) is connected to the inlet end of the regulating pool (4) through a pipe, the outlet end of the regulating pool (4) is connected to the inlet end of the hydrolysis acidification pool (5) through a pipe, the outlet end of the hydrolysis acidification pool (5) is connected to the inlet end of the sludge sedimentation pool (6) through a pipe, the outlet end of the sludge sedimentation pool (6) is connected to the inlet end of the aerobic decarbonization pool (7) through a pipe, the outlet end of the aerobic decarbonization pool (7) is connected to the inlet end of the secondary sedimentation pool (8) through a pipe, and the outlet end of the secondary sedimentation pool (8) is connected to the inlet end of the clear water pool (9) through a pipe.
2. The wastewater treatment system for board production according to claim 1, characterized in that, The oil scraping device is an oil scraper (15). The oil scraper (15) is horizontally positioned in the oil separator (2) near the liquid surface. The oil outlet of the oil scraper (15) is connected to the oil inlet of the oil separator (23) through an oil outlet pipe. The oil outlet of the oil separator (23) is connected to the oil inlet of the waste oil collection tank (24) through a pipe.
3. The wastewater treatment system for board production according to claim 1, characterized in that, The flocculant dosing device includes a flocculant dosing tank (19) and a metering pump (20); the outlet of the flocculant dosing tank (19) is connected to the inlet of the metering pump (20) through a pipe, and the outlet of the metering pump (20) extends into the secondary sedimentation tank (8) through a pipe, and the outlet of the pipe is located 0.3-0.5m below the liquid surface of the secondary sedimentation tank (8).
4. The wastewater treatment system for board production according to claim 1, characterized in that, The inlet pipe of the oil separator (2) is equipped with a booster pump (10), a flow meter (11) and a regulating valve (12) in sequence along the water flow direction; a level gauge (16) is installed at the bottom of the water storage tank (1) and the bottom of the regulating tank (4), and the detection end of the level gauge (16) is 0.1-0.2m higher than the bottom of the tank. An oil scraping device is installed in the oil separator (2), which uses a chain drive to push the rubber scraper to scrape off the residual grease in the production of the board, and then performs three-stage sedimentation and oil separation.
5. The wastewater treatment system for board production according to claim 1, characterized in that, The aeration devices of the regulating tank (4) and the hydrolysis acidification tank (5) are both perforated aeration pipes (25), and the aeration device of the aerobic decarbonization tank (7) is a microporous aeration head (18); the air inlet of the perforated aeration pipe (25) and the microporous aeration head (18) are connected to the air outlet of the Roots blower (17) through a pipeline. A fiberglass grating support is installed above the perforated aeration pipe (25) in the hydrolysis acidification tank (5). Volcanic rock glass ball packing is evenly laid on the packing support, and the packing volume accounts for 35% of the effective volume of the hydrolysis acidification tank (5).
6. The wastewater treatment system for board production according to claim 1, characterized in that, The inlet pipe of the hydrolysis acidification tank (5) is equipped with a booster pump (10), a flow meter (11) and a regulating valve (12) in sequence along the water flow direction. The sludge sedimentation tank (6) is equipped with an internal reflux pump (13). The inlet end of the internal reflux pump (13) is connected to the bottom of the sludge sedimentation tank (6), and the outlet end is connected to the upper part of the sludge sedimentation tank (6) through a pipe to form an internal circulation. The sludge sedimentation tank (6) is connected to the hydrolysis acidification tank (5) through a sludge return pipe. A sludge return pump (14), a flow meter (11) and a regulating valve (12) are sequentially installed on the sludge return pipe along the sludge flow direction. The inlet end of the sludge return pump (14) is connected to the bottom of the sludge sedimentation tank (6), and the outlet end is connected to the middle of the hydrolysis acidification tank (5) through the sludge return pipe.
7. The wastewater treatment system for board production according to claim 1, characterized in that, A sludge scraper is installed in the secondary sedimentation tank (8), and the scraper blade of the sludge scraper is set close to the bottom of the secondary sedimentation tank (8). The secondary sedimentation tank (8) is connected to the hydrolysis acidification tank (5) through the first sludge return pipe, to the aerobic decarbonization tank (7) through the second sludge return pipe, and to the plate and frame filter press (21) through the remaining sludge pipe. The first sludge return pipe, the second sludge return pipe and the remaining sludge pipe are each equipped with a sludge return pump (14), a flow meter (11) and a regulating valve (12) in sequence along the sludge flow direction; the filtrate outlet of the plate and frame filter press (21) is connected to the inlet of the filtrate collection tank (22) through a pipe, and the outlet of the filtrate collection tank (22) is connected to the inlet of the regulating tank (4) through a pipe.
8. The wastewater treatment system for board production according to claim 1, characterized in that, The tops of the equalization tank (4), hydrolysis acidification tank (5), sludge sedimentation tank (6), and aerobic decarbonization tank (7) are all sealed with fiberglass gas collection hoods. The edges of the fiberglass gas collection hoods are sealed to the flanges at the top of the tanks, and the top of the gas collection hoods is equipped with exhaust gas outlet pipes.