Method for treating fine chemical wastewater by using aerobic granular sludge based on AOA-SBR
By using an anaerobic-aerobic-anoxic cycle to cultivate aerobic granular sludge in an AOA-SBR reactor, the problems of difficult treatment and poor effluent quality of fine chemical wastewater were solved. This achieved efficient pollutant removal, meeting the first-class discharge standard, and avoiding the use of chemical reagents and secondary pollution.
Patent Information
- Application Number
- CN202610153009.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-03
- Publication Date
- 2026-03-17
AI Technical Summary
Fine chemical wastewater has a complex composition and contains substances that are difficult to degrade. Traditional treatment methods result in poor effluent quality and are difficult to treat. Furthermore, existing technologies have not been able to effectively meet the Class I standard in the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" GB18918-2002.
An AOA-SBR reactor was used to cultivate aerobic granular sludge in an anaerobic-aerobic-anoxic cycle. Through the microbial action in the anaerobic, aerobic and anoxic stages, facultative anaerobic and aerobic microorganisms were formed, gradually forming aerobic granular sludge, thus achieving efficient removal of COD, total nitrogen, total phosphorus and ammonia nitrogen.
The system achieves that the effluent from fine chemical wastewater meets the Class I standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" GB18918-2002, with COD less than 50 mg/L, total nitrogen less than 15 mg/L, total phosphorus less than 0.5 mg/L, and ammonia nitrogen less than 5 mg/L, and the effluent is stable, avoiding secondary pollution.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of fine chemical industrial wastewater treatment technology, specifically relating to a method for treating fine chemical wastewater using aerobic granular sludge based on AOA-SBR. Background Technology
[0002] Fine chemical wastewater is complex in composition, containing recalcitrant substances such as phenols, benzene compounds, and heterocyclic compounds. Wastewater treatment in the fine chemical industry faces numerous challenges, primarily due to its complex composition, high pollutant concentrations, and the sensitivity of the treatment process to operating conditions. Fine chemical wastewater typically contains various organic solvents, aromatic compounds, and reaction intermediates, with a chemical oxygen demand (COD) as high as 6000 mg / L, and is often deficient in nutrients, further increasing the difficulty of treatment. Furthermore, fine chemical processes often operate in batch or semi-batch mode, resulting in significant fluctuations in wastewater quality.
[0003] Traditional methods for removing wastewater from the fine chemical industry include activated sludge process, Fenton oxidation process, ozone oxidation process, activated carbon adsorption process, and coagulation process. Among them, the traditional activated sludge process includes pretreatment, aeration, sludge-water separation and sludge treatment, resulting in poor effluent quality. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention provides a method for treating fine chemical wastewater using aerobic granular sludge based on AOA-SBR.
[0005] To facilitate understanding of this invention, the materials used in this invention and their abbreviations are listed below: Dissolved oxygen (DO). Chemical oxygen demand (COD). Total nitrogen (TN). Total phosphorus (TP). Ammonia nitrogen (NH4). + -N. Sludge concentration, abbreviated as MLSS. Biomass concentration, abbreviated as MLVSS. Sludge settling ratio, abbreviated as SV. Sludge volume index, abbreviated as SVI. Total suspended solids, abbreviated as TSS. Sequencing batch reactor, abbreviated as SBR reactor.
[0006] The purpose of this invention is to provide a method for treating fine chemical wastewater using aerobic granular sludge based on AOA-SBR, comprising the following steps: The activated sludge is inoculated into a water-containing SBR reactor, aerated, and the upper layer of floating sludge is removed.
[0007] The reactor employs an anaerobic-aerobic-anoxic cycle: anaerobic time comprises 25%–30%, aerobic time 27%–30%, and anoxic time 20%–25% in each cycle. Aeration occurs during the aerobic phase, and the upper sludge layer is removed at the end of aeration. Five to ten minutes after sludge removal, effluent is introduced and discharged. Fine chemical wastewater flows into the SBR reactor from the bottom, and effluent exits from the top. This anaerobic-aerobic-anoxic cycle is continuously repeated for 188–212 cycles, increasing the diameter of the activated sludge to at least 200 μm, forming aerobic granular sludge.
[0008] During the first 3-7 days of the anaerobic-aerobic-anoxic cycle, the effluent is recycled and re-entered into the anaerobic-aerobic-anoxic cycle. After 3-7 days, the effluent is directly discharged into the environment. At this time, the diameter of the activated sludge increases to 130-150 μm.
[0009] After aerobic granular sludge is formed, an anaerobic-aerobic cycle is adopted: the aerobic time accounts for 30%~45% and the anaerobic time accounts for 55%~70% in each anaerobic-aerobic cycle. During the aerobic phase, strong aeration and micro-aeration are performed sequentially. At the end of micro-aeration, the upper layer of sludge is discharged. 5~10 minutes after the upper layer of sludge is discharged, the influent and effluent are then directly discharged. The anaerobic-aerobic cycle is continued until the diameter of the aerobic granular sludge increases to ≥500μm, forming mature aerobic granular sludge. After the formation of mature aerobic granular sludge, the anaerobic-aerobic cycle continues, with bottom granular sludge being discharged at least once a week.
[0010] During the anaerobic and aerobic phases, internal circulation occurs within the SBR reactor.
[0011] The water quality treated by the aerobic granular sludge treatment method for fine chemical wastewater based on AOA-SBR of this invention meets the Class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" GB18918-2002, namely, COD less than 50 mg / L, total nitrogen less than 15 mg / L, total phosphorus less than 0.5 mg / L, and ammonia nitrogen less than 5 mg / L.
[0012] Preferably, the SBR reactor is equipped with an inlet and an aeration device at the bottom, pH, ORP, and DO monitoring probes in the lower middle section, an outlet at the highest effective water depth, and a sludge discharge outlet 10cm-15cm below the highest effective water depth. The inlet, aeration device, and pH, ORP, and DO monitoring probes are all automatically controlled by a PLC.
[0013] Preferably, a mass flow meter is installed after the aeration device to control the aeration volume, and a stop valve is installed after the mass flow meter to prevent water backflow and contamination of the flow meter.
[0014] Preferably, the inoculum amount of the activated sludge is 7000 mg / L to 10000 mg / L.
[0015] Preferably, the dissolved oxygen content in the water of the SBR reactor during the anaerobic stage is 0.2 mg / L to 0.5 mg / L; the dissolved oxygen content in the water of the SBR reactor during the aerobic stage is 2.5 mg / L to 3 mg / L; and the dissolved oxygen content in the water of the SBR reactor during the anoxic stage is less than 0.2 mg / L. Herein, dissolved oxygen refers to oxygenated compounds dissolved in the water. In the anoxic and anaerobic stages, the oxygen content is close to zero.
[0016] Preferably, the duration of each anaerobic-aerobic-hypoxic cycle is at least 6 hours. The duration of each anaerobic-hypoxic cycle is at least 4.8 hours.
[0017] Preferably, the influent and effluent volumes in the anaerobic-aerobic-anoxic mode cycle are 20% to 25% of the effective volume of the SBR reactor, and the flow rate is 2.5 L / min to 3 L / min.
[0018] Preferably, the aerobic stage requires aeration, with an aeration rate of 2.5 L / min to 3.5 L / min.
[0019] Preferably, the amount of sludge discharged from the upper layer is 3% to 5% of the effective volume of the SBR reactor, and the proportion of activated sludge is controlled at 8000 mg / L to 12000 mg / L.
[0020] Preferably, the duration of strong aeration is 15%~20%, and the dissolved oxygen content is 3.5mg / L~4mg / L. The duration of micro-aeration is 30%~40%, and the dissolved oxygen content is 1.5mg / L~3mg / L.
[0021] Preferably, the volume in the anaerobic-aerobic mode cycle is 25% to 30% of the effective volume of the SBR reactor, and the rate is 2.5 L / min to 3 L / min.
[0022] Preferably, the diameter of the bottom granular sludge is greater than 1300 μm, and the discharge amount of the bottom granular sludge is 0.5% to 1% of the effective volume.
[0023] Preferably, after the mature aerobic granular sludge is formed, the hydraulic retention time is controlled at 12h~13h.
[0024] Preferably, the chemical oxygen demand of the fine chemical wastewater is 540 mg / L to 2160 mg / L, the total nitrogen is 57.4 mg / L to 142.2 mg / L, the total phosphorus is 3.4 mg / L to 5.9 mg / L, and the salinity is 0.5% to 2.5%.
[0025] Preferably, the effluent has a COD of less than 50 mg / L, total nitrogen of less than 15 mg / L, total phosphorus of less than 0.5 mg / L, ammonia nitrogen of less than 5 mg / L, and SVI of less than 5 mg / L. 30 The value is 20 mL / g to 40 mL / g.
[0026] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention relates to a method for treating fine chemical wastewater using aerobic granular sludge based on an AOA-SBR reactor. Aerobic granular sludge is cultivated in an anaerobic-aerobic-anoxic mode within an SBR reactor. Through cycles of anaerobic, aerobic, and anoxic processes, the activated sludge contains a variety of microorganisms, including aerobic, facultative anaerobic, and anaerobic microorganisms. The continuous growth of these microorganisms forms aerobic granular sludge, and the diverse microbial composition broadens the range of pollutants that can be treated, thus improving the treatment efficiency for fine chemical wastewater. Therefore, this invention achieves the Class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" GB18918-2002, namely, COD less than 50 mg / L, total nitrogen less than 15 mg / L, total phosphorus less than 0.5 mg / L, and ammonia nitrogen less than 5 mg / L. The SVI in the effluent is also reduced. 30 The concentration is 20 mL / g to 40 mL / g. Furthermore, the effluent from this invention has stable water quality, and no other chemical reagents need to be added during the process, thus preventing secondary pollution.
[0027] This invention discloses a method for treating fine chemical wastewater using aerobic granular sludge based on an AOA-SBR reactor. The method involves inoculating activated sludge into a water-containing SBR reactor, aerating the sludge, and removing the upper layer of floating sludge. The inoculated activated sludge provides a sludge medium for cultivating aerobic granular sludge. The sludge concentration must be neither too high nor too low; too low a concentration results in low treatment efficiency, while too high a concentration affects dissolved oxygen (DO) detection, leading to discrepancies between actual and measured DO, thus impacting the treatment effect.
[0028] The system employs an anaerobic-aerobic-anoxic cycle. In each cycle, the anaerobic time accounts for 25%–30%, the aerobic time 27%–30%, and the anoxic time 20%–25%. Aeration occurs during the aerobic phase, and the upper sludge layer is discharged at the end of aeration. After the upper sludge layer is discharged, effluent is influent and effluent are processed within 5–10 minutes. During influent and effluent processing, fine chemical wastewater flows in from the bottom of the SBR reactor, and effluent exits from the top of the reactor during influent. With continuous anaerobic-aerobic-anoxic cycle, the diameter of the activated sludge increases to at least 200 μm, forming aerobic granular sludge. For the first 3–7 days of the anaerobic-aerobic-anoxic cycle, the effluent is recycled and re-entered into the anaerobic-aerobic-anoxic cycle. After 7 days, the effluent is directly discharged. The system operates in an anaerobic-aerobic-anoxic mode to remove nitrogen, phosphorus, and COD. In the anaerobic stage, microorganisms absorb COD, converting external carbon sources into internal carbon sources for storage, while phosphorus-releasing bacteria release phosphorus. In the aerobic stage, nitrifying bacteria absorb oxygen and undergo nitrification, converting ammonia nitrogen into nitrate nitrogen. Polyphosphate-accumulating bacteria absorb phosphorus. In the anoxic stage, denitrifying bacteria utilize the stored internal carbon sources to undergo denitrification, converting nitrate nitrogen into nitrogen gas.
[0029] After aerobic granular sludge is formed, an anaerobic-aerobic cycle is adopted. In each anaerobic-aerobic cycle, the aerobic time accounts for 30%–45%, and the anaerobic time accounts for 55%–70%. During the aerobic phase, strong aeration and micro-aeration are performed sequentially. Strong and micro-aeration maintain sufficient oxygen to ensure more complete nitrification. At the end of micro-aeration, the upper layer of sludge is discharged. After discharging the upper layer of sludge, effluent is influent and effluent is discharged directly after 5–10 minutes. The anaerobic-aerobic cycle is continued until the diameter of the aerobic granular sludge increases to ≥500 μm, forming mature aerobic granular sludge. After the formation of mature aerobic granular sludge, the anaerobic-aerobic cycle continues, with bottom granular sludge being discharged at least once a week.
[0030] The wastewater treatment effects of Examples 1 to 1 of the present invention are similar. Taking Example 1 as an example, the COD in the effluent after 180 days was 25 mg / L to 46 mg / L, TN was 5.22 mg / L to 7.97 mg / L, TP was 0.21 mg / L to 0.40 mg / L, and NH4+ was... + -N ranges from 0.89 mg / L to 1.67 mg / L, SVI 30 The concentrations were 20 mL / g to 40 mL / g, nitrite nitrogen was 0.01 mg / L to 0.99 mg / L, and nitrate nitrogen was 0.01 mg / L to 0.98 mg / L. Comparative Example 2, which used activated sludge treatment, showed the best results, with effluent COD of 25 mg / L to 30 mg / L, TN of 15.12 mg / L to 20 mg / L, TP of 0.21 mg / L to 0.4 mg / L, and NH4+ of...+ -N ranges from 1.58 mg / L to 3.89 mg / L, SVI 30 The concentrations of nitrogen in the effluent were 40.12 mL / g to 60 mL / g, nitrite nitrogen was 0.00 mg / L to 0.99 mg / L, and nitrate nitrogen was 0.01 mg / L to 0.99 mg / L. The difference between Example 1 and Comparative Example 2 is that Example 1 used aerobic granular sludge, while Comparative Example 2 used activated granular sludge. The total nitrogen (TN) in the effluent of Comparative Example 2 was 15.12 mg / L to 20 mg / L, which did not meet the A standard (less than 15 mg / L). This indicates that aerobic granular sludge has a stronger treatment capacity for TN in fine chemical wastewater. Detailed Implementation
[0031] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the following detailed description, in conjunction with preferred embodiments, provides a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0032] It should be noted that all technical terms used in this invention are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.
[0033] I. Experimental Materials The main materials used in this invention are activated sludge and fine chemical wastewater.
[0034] The parameters for the activated sludge were purchased from Jinan Zhongkecheng Water Purification Co., Ltd. The fine chemical wastewater was purchased from Bloomage Biotechnology Co., Ltd., with COD ranging from 540 mg / L to 2160 mg / L, TN from 57.4 mg / L to 142.2 mg / L, TP from 3.4 mg / L to 5.9 mg / L, and NH4+... + -N ranges from 54 mg / L to 140 mg / L.
[0035] The SBR reactor used in this invention is made of acrylic and features a double-layered, sealed design with internal and external layers connected by a water bath system to maintain temperature stability. The inner tube of the SBR reactor has a diameter of 18cm, a height of 140cm, an effective height of 120cm, and an effective volume of 24L. During operation, the water depth is maintained at 120cm, and an overflow outlet is provided. From bottom to top, the SBR reactor is equipped with an inlet, an aeration device, a water distribution system, an electrode area, an internal circulation port, and an outlet. The bottom inlet is used to pump in raw wastewater and also serves as the inlet for the nitrification liquid in the anaerobic cycle stage. The aeration device uses high-temperature treated titanium alloy plates to ensure more uniform aeration and reduce resistance and the risk of clogging. The water distribution system uses perforated pipes to ensure uniform water distribution during influent. A monitoring probe, equipped with pH, ORP, and DO electrodes, is installed in the lower part of the reactor at a 120° angle to monitor process parameters; this probe is located 30cm from the bottom. The internal circulation port is located 10cm below the outlet, which is situated at the reactor's highest effective water depth. The system operates in a sequential batch mode and is controlled by a PLC.
[0036] II. Experimental Methods This invention detects water quality indicators including COD, TN, TP, and NH4. + -N, nitrate nitrogen, nitrite nitrogen.
[0037] MLSS in the SBR reactor is expressed by measuring the concentration of suspended solids in the mixed liquor. The biomass concentration in the sludge is expressed by the MLVSS of the mixed liquor. Sludge settling performance is represented by SVI. Considering the excellent settling properties of aerobic granular sludge, the sludge settling ratio (SVI) was specifically measured over 30 minutes. 30 To assess its settlement performance, SVI 30 The smaller the value, the better its settling and concentration properties.
[0038] COD, TN, TP, NH4 + -N, nitrate nitrogen, and nitrite nitrogen were all determined according to the methods in the "National Standard of the People's Republic of China - Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" GB18918-2002. MLSS, MLVSS, and SVI were also measured. 30 The sludge particle size was determined using the method specified in the National Standard of the People's Republic of China—Determination of Performance Indicators of Activated Sludge in Wastewater from Baijiu Industry (DB 34T / 2500-2015). The particle size was determined using the method specified in the National Standard of the People's Republic of China—Laser Diffraction Method for Particle Size Distribution (GB / T 19077.1-2008).
[0039] Example 1 A method for treating fine chemical wastewater using aerobic granular sludge based on AOA-SBR includes the following steps: Inoculate activated sludge into a water-containing SBR reactor at a concentration of 10,000 mg / L, aerate for 26 hours, and then remove the upper layer of floating sludge.
[0040] The reactor employs a cyclical anaerobic-aerobic-anoxic cycle. Each cycle lasts 8 hours, with 30% anaerobic time (0.5 mg / L dissolved oxygen), 30% aerobic time (3 mg / L dissolved oxygen), and 25% anoxic time (0.16 mg / L dissolved oxygen). During the aerobic phase, aeration is carried out at 3.5 L / min. At the end of aeration, 1.2 L of the supernatant sludge is discharged, maintaining the activated sludge concentration at 12000 mg / L. Ten minutes after discharging the supernatant sludge, 6 L of effluent is fed in at a rate of 3 L / min. Fine chemical wastewater flows into the SBR reactor from the bottom and exits from the top during influent. Through continuous anaerobic-aerobic-anoxic cycle, the diameter of the activated sludge increases to 250 μm, forming aerobic granular sludge. For the first 7 days of the anaerobic-aerobic-anoxic cycle, the effluent is recycled and re-entered into the anaerobic-aerobic-anoxic cycle. After 7 days, the effluent is discharged directly.
[0041] After aerobic granular sludge is formed, an anaerobic-aerobic cycle is adopted. Each anaerobic-aerobic cycle lasts for 6 hours, with aerobic time accounting for 45% and anaerobic time accounting for 55%. The aerobic phase involves sequential strong aeration and micro-aeration. Strong aeration accounts for 20% of the time with a dissolved oxygen content of 4 mg / L, while micro-aeration accounts for 40% with a dissolved oxygen content of 3 mg / L. At the end of micro-aeration, 1.2 L of the upper sludge is discharged, controlling the activated sludge content to 12000 mg / L. Ten minutes after discharging the upper sludge, 7.2 L of effluent is fed in and out at a rate of 3 L / min. During influent and effluent flow, fine chemical wastewater flows in from the bottom of the SBR reactor and effluent exits from the top of the reactor. The anaerobic-aerobic cycle continues until the diameter of the aerobic granular sludge increases to 550 μm, forming mature aerobic granular sludge. After the mature aerobic granular sludge is formed, the anaerobic-aerobic cycle continues to be used, with the hydraulic retention time controlled at 13h. Every 5 days, bottom granular sludge with a diameter greater than 1300μm is discharged, with a discharge volume of 0.24L of the effective volume.
[0042] The effluent water quality test results for Example 1 over a continuous 180-hour period are shown in Tables 1, 2, 3, and 4. The results show that the effluent water quality of the AOA-aerobic granular sludge process in Example 1 was stable at COD 25 mg / L~46 mg / L, TN 5.22 mg / L~7.97 mg / L, TP 0.21 mg / L~0.40 mg / L, and NH4+... +-N ranges from 0.89 mg / L to 1.67 mg / L, SVI 30 The concentrations are 20 mL / g to 40 mL / g, nitrite nitrogen is 0.01 mg / L to 0.99 mg / L, and nitrate nitrogen is 0.01 mg / L to 0.98 mg / L.
[0043] Table 1. Water quality test results from day 1 to day 50 of Example 1 Table 2. Water quality test results from day 51 to day 100 of Example 1 Table 3. Water quality test results from day 101 to day 150 of Example 1 Table 4. Water quality test results from day 151 to day 180 of Example 1 Example 2 A method for treating fine chemical wastewater using aerobic granular sludge based on AOA-SBR includes the following steps: Inoculate activated sludge into a water-containing SBR reactor at a concentration of 7000~10000 mg / L, aerate for 25 hours, and then remove the upper layer of floating sludge.
[0044] The reactor employs a cyclical anaerobic-aerobic-anoxic cycle. Each cycle lasts 7 hours, with anaerobic time comprising 27% (dissolved oxygen 0.3 mg / L), aerobic time comprising 28% (dissolved oxygen 2.7 mg / L), and anoxic time comprising 22% (dissolved oxygen 0.18 mg / L). During the aerobic phase, aeration is carried out at 3 L / min, and 1 L of supernatant sludge is discharged at the end of aeration, maintaining the activated sludge concentration at 10000 mg / L. After discharging the supernatant sludge for 7 minutes, 5 L of effluent is fed in and out at a rate of 2.7 L / min. Fine chemical wastewater flows in from the bottom of the SBR reactor during influent and effluent from the top during effluent flow. Through continuous anaerobic-aerobic-anoxic cycle, the diameter of the activated sludge increases to 250 μm, forming aerobic granular sludge. For the first 5 days of the anaerobic-aerobic-anoxic cycle, the effluent is recycled and re-entered into the anaerobic-aerobic-anoxic cycle. After 5 days, the effluent is discharged directly.
[0045] After aerobic granular sludge is formed, an anaerobic-aerobic cycle is adopted. Each anaerobic-aerobic cycle is 5 hours, with aerobic time accounting for 40% and anaerobic time accounting for 60%. The aerobic phase involves sequential strong aeration and micro-aeration. Strong aeration accounts for 17% of the time with a dissolved oxygen content of 3.7 mg / L, while micro-aeration accounts for 35% with a dissolved oxygen content of 2 mg / L. At the end of micro-aeration, 1 L of the upper sludge is discharged, controlling the activated sludge content to 10000 mg / L. Seven minutes after discharging the upper sludge, 7 L of effluent is fed in and out at a rate of 2.7 L / min. During influent and effluent flow, fine chemical wastewater flows in from the bottom of the SBR reactor and effluent exits from the top. The anaerobic-aerobic cycle continues until the diameter of the aerobic granular sludge increases to 520 μm, forming mature aerobic granular sludge. After the mature aerobic granular sludge is formed, the anaerobic-aerobic cycle continues to be used, with the hydraulic retention time controlled at 12.5h. The bottom granular sludge with a diameter greater than 1300μm is discharged every 6 days, with the discharge volume being 0.2L of the effective volume.
[0046] The effluent water quality test results for Example 2 over a continuous 180-hour period are shown in Tables 5, 6, 7, and 8. The results show that the effluent water quality of the AOA-aerobic granular sludge process in Example 2 was stable at COD 25 mg / L~46 mg / L, TN 5.22 mg / L~7.97 mg / L, TP 0.21 mg / L~0.4 mg / L, and NH4+... + -N ranges from 0.89 mg / L to 1.67 mg / L, SVI 30 The concentrations are 20.12 mL / g to 40 mL / g, nitrite nitrogen is 0.01 mg / L to 0.99 mg / L, and nitrate nitrogen is 0.01 mg / L to 0.98 mg / L.
[0047] Table 5. Water quality test results from day 1 to day 51 of Example 2 Table 6. Water quality test results from day 51 to day 100 of Example 2. Table 7. Water quality test results from day 101 to day 150 of Example 2 Table 8. Water quality test results from day 151 to day 180 of Example 2 Example 3 A method for treating fine chemical wastewater using aerobic granular sludge based on AOA-SBR includes the following steps: Inoculate the activated sludge into the aqueous SBR reactor at a concentration of 7000 mg / L, aerate for 25 hours, and then remove the upper layer of floating sludge.
[0048] The reactor employs a cyclical anaerobic-aerobic-anoxic cycle. Each cycle lasts 6 hours, with 25% anaerobic time (0.2 mg / L dissolved oxygen), 27% aerobic time (2.5 mg / L dissolved oxygen), and 20% anoxic time (0.2 mg / L dissolved oxygen). During the aerobic phase, aeration is carried out at 2.5 L / min. At the end of aeration, 0.72 L of supernatant sludge is discharged, maintaining the activated sludge concentration at 8000 mg / L. Five minutes after sludge discharge, 4.8 L of effluent is fed in and out at a rate of 2.5 L / min. Fine chemical wastewater flows in from the bottom of the SBR reactor during influent and effluent from the top. Through continuous anaerobic-aerobic-anoxic cycle, the diameter of the activated sludge increases to 200 μm, forming aerobic granular sludge. For the first 3 days of the anaerobic-aerobic-anoxic cycle, the effluent is recycled and re-entered into the anaerobic-aerobic-anoxic cycle. After 3 days, the effluent is discharged directly.
[0049] After aerobic granular sludge is formed, an anaerobic-aerobic cycle is adopted. Each anaerobic-aerobic cycle is 4.8 hours, with aerobic time accounting for 30% and anaerobic time accounting for 55%. The aerobic phase involves sequential strong aeration and micro-aeration. Strong aeration accounts for 15% of the time with a dissolved oxygen content of 3.5 mg / L, while micro-aeration accounts for 30% with a dissolved oxygen content of 1.5 mg / L. At the end of micro-aeration, 0.72 L of the upper sludge is discharged, controlling the activated sludge content to 8000 mg / L. Five minutes after discharging the upper sludge, 6 L of effluent is fed in at a rate of 2.5 L / min. During influent and effluent flow, fine chemical wastewater flows in from the bottom of the SBR reactor and effluent exits from the top. The anaerobic-aerobic cycle continues until the diameter of the aerobic granular sludge increases to 500 μm, forming mature aerobic granular sludge. After the mature aerobic granular sludge is formed, the anaerobic-aerobic cycle continues, with the hydraulic retention time controlled at 12 hours. Bottom granular sludge with a diameter greater than 1300 μm is discharged once a week, with a discharge volume of 0.12 L of the effective volume.
[0050] The effluent water quality test results for Example 3 over a continuous 180-hour period are shown in Tables 9, 10, 11, and 12. The results show that the effluent water quality of the AOA-aerobic granular sludge process in Example 3 was stable at COD 25 mg / L~46 mg / L, TN 5.18 mg / L~7.98 mg / L, TP 0.2 mg / L~0.4 mg / L, and NH4+... + -N ranges from 0.89 mg / L to 1.67 mg / L, SVI 30The concentrations are 20 mL / g to 40 mL / g, nitrite nitrogen is 0.01 mg / L to 0.98 mg / L, and nitrate nitrogen is 0.00 mg / L to 0.99 mg / L.
[0051] Table 9. Water quality test results for Example 3 from 1 to 50 days. Table 10. Water quality test results for Example 3 from 51 to 100 days. Table 11 Water quality test results of Example 3 from 101 to 150 days Table 12 Water quality test results of Example 3 at 150-151 days Comparative Example 1 A method for treating fine chemical wastewater with AO activated sludge includes the following steps: Activated sludge is inoculated into the SBR wastewater treatment system and aerated for more than 24 hours. The upper layer of floating sludge is then removed, and the sludge concentration in the system is 6000 mg / L. DO, pH, and ORP probes need to be placed in the processor for real-time monitoring. A mass flow meter is added after the aeration equipment to stably control the aeration rate. A stop valve is connected after the mass flow meter to prevent water backflow and contamination of the flow meter.
[0052] The SBR (Sequencing Batch Reactor) operates using a top-in, top-out configuration for water intake and discharge. The cultivation phase employs an anaerobic-aerobic-anoxic cycle to treat fine industrial wastewater, operating four times daily for 360 minutes each. The process involves sedimentation, simultaneous influent and effluent discharge, agitation, and aeration. The single-cycle effluent ratio can reach 20% of the system's capacity, with a daily treatment capacity of 30L. Fine industrial wastewater can be used as the raw water for cultivation. Anaerobic time should account for 30% of the total time, aerobic time for 30%, and sedimentation time should be at least 40 minutes. Dissolved oxygen is controlled at 2.5 mg / L, and the aeration rate is 3.5 L / min. At the end of each cycle, the upper layer of sludge is removed, accounting for 3% of the total effective system volume. MLSS (Mixed Liquor Sulfate) is measured daily and maintained at 6000 mg / L. The frequency and amount of sludge removal are controlled based on the sludge concentration.
[0053] The effluent water quality test results for Comparative Example 1 over a continuous 180-hour period are shown in Tables 13, 14, 15, and 16. The results show that the COD of the effluent from the AO-activated sludge process in Comparative Example 1 was 350 mg / L–500 mg / L, TN was 45 mg / L–70 mg / L, TP was 3 mg / L–5 mg / L, and NH4+ was [not specified in the original text]. + -N is 120mg / L~150mg / L, SVI 30The concentrations are 120 mL / g to 150 mL / g, nitrite nitrogen is 0.01 mg / L to 0.99 mg / L, and nitrate nitrogen is 0.01 mg / L to 0.98 mg / L.
[0054] Table 13 Water quality test results for Comparative Example 1 from day 1 to day 50 Table 14 Water quality test results for Comparative Example 1 from day 51 to day 100 Table 15 Water quality test results of Comparative Example 1 from day 101 to day 150 Table 16 Water quality test results of Comparative Example 1 from day 151 to day 180 Comparative Example 2 A method for treating fine chemical wastewater using activated sludge based on AOA-SBR includes the following steps: Activated sludge is inoculated into the SBR wastewater treatment system and aerated for more than 24 hours. The top layer of floating sludge is then removed, and the sludge concentration in the system is 5000 mg / L. DO, pH, and ORP probes need to be placed in the processor for real-time monitoring. A mass flow meter is added after the aeration equipment to stably control the aeration rate. A stop valve is connected after the mass flow meter to prevent backflow and contamination of the flow meter.
[0055] The SBR (Sequencing Batch Reactor) operation mode adopts simultaneous top influent and top effluent, with influent entering before effluent exiting. The cultivation stage uses an anaerobic-aerobic-anoxic operating mode to treat fine industrial wastewater, operating four cycles per day, each cycle lasting 360 minutes. The process involves sedimentation, influent, effluent, mixing, and aeration. The single-cycle effluent ratio can reach 20% of the system's capacity, with a daily treatment capacity of 50L. Fine industrial wastewater can be used as raw water for cultivation. Anaerobic time should account for 30%, aerobic time for 30%, and sedimentation time should be at least 40 minutes. Dissolved oxygen is controlled at 2.5 mg / L, and the aeration rate is 3.5 L / min. At the end of each cycle, the upper layer of sludge is discharged, with the discharged sludge volume accounting for 3% of the total effective system volume. MLSS (Mixed Liquor Sulfate) is measured daily and controlled at 6000 mg / L. The frequency and amount of sludge discharge are controlled based on the sludge concentration.
[0056] The effluent water quality test results for Comparative Example 2 over 180 consecutive days are shown in Tables 17, 18, 19, and 20. The results show that the effluent COD of the AOA-activated sludge process in Comparative Example 2 was 25 mg / L–30 mg / L, TN was 15.12 mg / L–20 mg / L, TP was 0.21 mg / L–0.4 mg / L, and NH4+ was [not specified in the original text]. +-N ranges from 1.58 mg / L to 3.89 mg / L, SVI 30 The concentrations are 40.12 mL / g to 60 mL / g, nitrite nitrogen is 0.00 mg / L to 0.99 mg / L, and nitrate nitrogen is 0.01 mg / L to 0.99 mg / L.
[0057] Table 17 Water quality test results for Comparative Example 2 from day 1 to day 50 Table 18 shows the water quality test results for Comparative Example 2 from day 51 to day 100. Table 19 Water quality test results of Comparative Example 2 from day 101 to day 150 Table 20 Water quality test results of Comparative Example 2 from day 151 to day 180 Comparative Example 3 A method for treating fine chemical wastewater using activated sludge based on AAO-SBR includes the following steps: Inoculate activated sludge into the SBR wastewater treatment system and aerate for at least 24 hours. Remove the top layer of floating sludge. The sludge concentration in the system should be 6000 mg / L. DO, pH, and ORP probes should be placed in the processor for real-time monitoring. A mass flow meter should be added after the aeration equipment to stably control the aeration rate. A stop valve should be connected after the mass flow meter to prevent backflow and contamination of the flow meter.
[0058] The SBR (Sequencing Batch Reactor) operates in a top-inlet, top-outlet, or first-in-last-outlet mode. The cultivation phase employs an anaerobic-anoxic-aerobic cycle to treat fine industrial wastewater, operating four times daily for 360 minutes each cycle. The process involves sedimentation, inlet, outlet, mixing, and aeration. The single-cycle effluent ratio can reach 20% of the system's capacity, with a daily treatment capacity of 50L. Fine industrial wastewater can be used as the raw water for cultivation. Anaerobic time should account for 30%, aerobic time for 30%, and sedimentation time should be at least 60 minutes. Dissolved oxygen is controlled at 2.5 mg / L, and the aeration rate is 3.5 L / min. At the end of each cycle, the upper layer of sludge is removed, accounting for 3% of the total effective system volume. MLSS (Mixed Liquor Sulfate) is measured daily and maintained at 6000 mg / L. The frequency and amount of sludge removal are controlled based on the sludge concentration.
[0059] The effluent water quality test results for Comparative Example 3 over a continuous 180-hour period are shown in Tables 21, 22, 23, and 24. The results show that the effluent COD of the AAO-activated sludge process in Comparative Example 3 ranged from 357 mg / L to 501 mg / L, TN from 45.09 mg / L to 70 mg / L, TP from 3.09 mg / L to 5 mg / L, and NH4+... + -N ranges from 35.12 mg / L to 45 mg / L, SVI 30 The concentrations are 70.12 mL / g to 100 mL / g, nitrite nitrogen is 0.01 mg / L to 0.99 mg / L, and nitrate nitrogen is 0.00 mg / L to 0.98 mg / L.
[0060] Table 21 Water quality test results for Comparative Example 3 from day 1 to day 50 Table 22 shows the water quality test results of Comparative Example 3 from day 51 to day 100. Table 23 Water quality test results of Comparative Example 3 from day 101 to day 150 Table 24 shows the water quality test results of Comparative Example 3 from day 151 to day 180. It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described in this invention to avoid redundancy. Although preferred embodiments of this invention have been described, those skilled in the art, once they understand the inventive concept of this invention, can make other changes and modifications to these embodiments, and all such changes and modifications fall within the scope of this invention.
[0061] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If such modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.
Claims
1. A method for treating fine chemical wastewater by aerobic granular sludge based on AOA-SBR, characterized in that, Comprising the following steps: Inoculate activated sludge in an aqueous SBR reactor, aerate, and remove supernatant sludge; Adopt an anaerobic-aerobic-anoxic mode cycle: the anaerobic time in each anaerobic-aerobic-anoxic mode cycle accounts for 25%-30%, the aerobic time accounts for 27%-30%, and the anoxic time accounts for 20%-25%; the aerobic stage is aerated, and the supernatant sludge is removed at the end of aeration; 5-10 minutes after the supernatant sludge is removed, water is fed and discharged, and the fine chemical wastewater flows into the SBR reactor from the bottom while the water is discharged from the top of the SBR reactor; continue the anaerobic-aerobic-anoxic mode cycle, and the diameter of the activated sludge increases to greater than or equal to 200 μm to form aerobic granular sludge; 3-7 days before the anaerobic-aerobic-anoxic mode cycle, the effluent is recovered and re-entered into the anaerobic-aerobic-anoxic mode cycle; after 3-7 days, the effluent is directly discharged; After the aerobic granular sludge is formed, an anaerobic-aerobic mode cycle is adopted: the aerobic time in each anaerobic-aerobic mode cycle accounts for 30%-45%, and the anaerobic time accounts for 55%-70%; the aerobic stage is performed in turn by strong aeration and micro-aeration, the supernatant sludge is removed at the end of micro-aeration, 5-10 minutes after the supernatant sludge is removed, water is fed and discharged, and the effluent is directly discharged; continue the anaerobic-aerobic mode cycle, and when the diameter of the aerobic granular sludge increases to greater than or equal to 500 μm, mature aerobic granular sludge is formed; after the mature aerobic granular sludge is formed, continue to adopt the anaerobic-aerobic mode cycle, and at least once a week, the bottom granular sludge is discharged.
2. The method for treating fine chemical wastewater by using AOA-SBR based aerobic granular sludge according to claim 1, characterized in that, The inoculation amount of the activated sludge is 7000 mg / L-10000 mg / L.
3. The method for treating fine chemical wastewater by using AOA-SBR based aerobic granular sludge according to claim 1, characterized in that, The dissolved oxygen content in the water body in the SBR reactor during the anaerobic stage is 0.2 mg / L-0.5 mg / L; the dissolved oxygen content in the water body in the SBR reactor during the aerobic stage is 2.5 mg / L-3 mg / L; and the dissolved oxygen content in the water body in the SBR reactor during the anoxic stage is less than 0.2 mg / L.
4. The method for treating fine chemical wastewater by using AOA-SBR based aerobic granular sludge according to claim 1, characterized in that, The time of each anaerobic-aerobic-anoxic mode cycle is at least 6 h, and the time of each anaerobic-anoxic mode cycle is at least 4.8 h.
5. The method for treating fine chemical wastewater by using AOA-SBR based aerobic granular sludge according to claim 1, characterized in that, The volume of the water fed and discharged in the anaerobic-aerobic-anoxic mode cycle is 20%-25% of the effective volume of the SBR reactor, and the speed is 2.5 L / min-3 L / min.
6. The method for treating fine chemical wastewater by using AOA-SBR based aerobic granular sludge according to claim 1, characterized in that, The aerobic stage needs to be aerated, and the aeration amount is 2.5 L / min-3.5 L / min.
7. The method for treating fine chemical wastewater by using AOA-SBR based aerobic granular sludge according to claim 1, characterized in that, The sludge discharge amount of the supernatant sludge is 3%-5% of the effective volume of the SBR reactor, and the activated sludge accounts for 8000 mg / L-12000 mg / L.
8. The method for treating fine chemical wastewater by using AOA-SBR based aerobic granular sludge according to claim 1, characterized in that, The time ratio of the strong aeration is 15%-20%, and the dissolved oxygen content is 3.5 mg / L-4 mg / L; the time ratio of the micro-aeration is 30%-40%, and the dissolved oxygen content is 1.5 mg / L-3 mg / L.
9. The method for treating fine chemical wastewater by using AOA-SBR based aerobic granular sludge according to claim 1, characterized in that, The volume in the anaerobic-aerobic mode cycle is 25%-30% of the effective volume of the SBR reactor, and the speed is 2.5 L / min-3 L / min.
10. The method for treating fine chemical wastewater by using AOA-SBR based aerobic granular sludge according to claim 1, characterized in that, The diameter of the bottom layer granular sludge is greater than 1300 μm, and the discharge amount of the bottom layer granular sludge is 0.5% to 1% of the effective volume.