Two-stage coupling type granular sludge system and method for treating printing and dyeing wastewater with high carbon-nitrogen ratio through autotrophic nitrogen removal by two-stage coupling type granular sludge system

Abstract

The invention belongs to the technical field of printing and dyeing wastewater treatment and recycling, and discloses a method for treating high-carbon-nitrogen-ratio printing and dyeing wastewater by a two-stage coupled granular sludge system and a regulation and control strategy. The system comprises an efficient anaerobic granular sludge reactor and a micro-aerobic granular sludge reactor driven by iron circulation. The system provided by the invention is provided with an adjustable reflux mechanism, and when organic matters in effluent instantly rise due to HRT adjustment of an anaerobic section, real-time regulation and control are carried out by increasing micro-aerobic section effluent to flow back to anaerobic inlet water, so that the stability of the system is guaranteed, and the effluent reaches the standard. According to the method, the total nitrogen removal rate is not less than 85%, the COD removal rate is not less than 95%, the chroma removal rate is not less than 90%, and the methane yield is not less than 0.25 L / g COD.

Description

Technical Field

[0001] This application relates to the field of dyeing and printing wastewater treatment and process control technology, and in particular to a two-stage coupled granular sludge system and its method for autotrophic denitrification treatment of dyeing and printing wastewater with a high carbon-to-nitrogen ratio. Background Technology

[0002] The dyeing and printing wastewater has a high concentration of organic matter, deep color, and many difficult-to-degrade components, among which azo dyes are the main color-producing substances. In the traditional "anaerobic + aerobic" process, the anaerobic stage can break the azo bonds of azo dyes to generate colorless but more toxic aromatic amine intermediates; the aerobic stage is responsible for further mineralizing the aromatic amines. However, this process has the following prominent problems: (1) the anaerobic stage cannot achieve energy recovery; (2) the aerobic stage relies on a large amount of aeration, resulting in high energy consumption and large sludge production; (3) aromatic amines are prone to accumulate when degradation is incomplete in the aerobic stage, and there is still an ecological risk in the effluent; (4) the process has poor resistance to load fluctuations, and changes in HRT and water quality can easily lead to effluent exceeding the standard; (5) the process has limited capacity for total nitrogen removal.

[0003] For dyeing and printing wastewater with a high carbon-to-nitrogen ratio, achieving efficient organic matter conversion and methane recovery in the anaerobic stage, and then coupling efficient denitrification and degradation of recalcitrant organic matter in subsequent stages, will greatly improve the resource utilization level and treatment efficiency of the process. Microaerobic granular sludge possesses a dissolved oxygen gradient, which can simultaneously enrich functional microorganisms such as ammonia-oxidizing bacteria, anaerobic ammonia-oxidizing bacteria, and iron-oxidizing / reducing bacteria, providing possibilities for short-range nitrogen conversion and iron-cycle denitrification. Furthermore, the non-specific ammonia nitrogen oxygenation enzymes of ammonia-oxidizing bacteria can co-degrade aromatic amines, providing a new pathway for the advanced treatment of dyeing and printing wastewater.

[0004] However, how to coordinate the HRT of the anaerobic section with the influent load of the microaerobic section in actual operation, how to prevent the passivation of iron oxides, how to achieve efficient mineralization and degradation of aniline organic matter, and how to quickly restore system stability when the process fluctuates are still key challenges in the engineering of this technology.

[0005] Based on the above background, this invention proposes to dynamically change the penetration depth of dissolved oxygen in microaerobic granular sludge by regulating the concentration of organic matter in the influent of a microaerobic granular sludge reactor, forming a non-fixed microaerobic / anoxic region, reactivating inert crystalline iron oxides, promoting iron redox cycles, and thus completing denitrification and mineralization of recalcitrant organic matter. Summary of the Invention

[0006] This invention aims to provide a two-stage coupled granular sludge process that can simultaneously achieve dye decolorization, methane recovery, efficient denitrification, and aromatic amine degradation, and ensures long-term stable operation of the system through parameter control and reflux mechanisms.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A method for treating high carbon-to-nitrogen ratio dyeing and printing wastewater using a two-stage coupled granular sludge system includes:

[0009] (1) Anaerobic stage process and control: High carbon-to-nitrogen ratio dyeing wastewater is fed into a high-efficiency anaerobic granular sludge reactor, and the hydraulic retention time (HRT) is controlled to be sludge concentration and every Adjust the HRT once a day, the adjustment range is... During this process, the azo dye undergoes reduction and decolorization, generating aromatic amine intermediates; most of the easily degradable organic matter is converted into methane for collection, with a COD removal rate of ≥80%.

[0010] (2) Microaerobic stage process and control: Anaerobic effluent enters the microaerobic granular sludge reactor, and the concentration of organic matter in the influent is controlled at [value missing]. Dissolved oxygen concentration is And add iron salts ;

[0011] By controlling the HRT in the anaerobic section or using reflux dilution, the influent COD can be stabilized at a certain level. Control DO as Add Iron salts are used to maintain the total iron concentration. By utilizing natural or artificial fluctuations in the concentration of organic matter in the influent, the dissolved oxygen penetration depth inside the granular sludge is induced to change periodically, thereby activating the passivated crystalline iron oxides and promoting the iron redox cycle.

[0012] The synergistic removal mechanism of pollutants in microaerobic granular sludge: ammonia-oxidizing bacteria perform partial nitrification under low oxygen conditions, providing nitrite; anaerobic ammonia-oxidizing bacteria utilize... and Denitrification is carried out; iron oxidizing / reducing bacteria participate in the iron cycle and promote the iron ammonia oxidation process; ammonia oxidizing bacteria degrade aromatic amines produced in the anaerobic stage through cometabolism, thereby achieving the mineralization of recalcitrant organic matter.

[0013] (3) System anti-disturbance control strategy: When the HRT adjustment in the anaerobic section causes the effluent organic matter concentration to instantaneously exceed the set threshold, the reflux control mechanism is activated to reflux part of the effluent from the microaerobic section to the influent from the anaerobic section. The reflux ratio is... .

[0014] When the anaerobic section experiences changes in effluent due to HRT adjustments or sudden changes in influent load... or At that time, the reflux control mechanism will be automatically activated to... The effluent from the microaerobic section is returned to the influent from the anaerobic section to dilute the influent load, stabilize the water quality, and prevent subsequent treatment units from exceeding the standards.

[0015] Preferably, the HRT adjustment range of the high-efficiency anaerobic granular sludge reactor in step (1) is: .

[0016] Preferably, the iron salt in step (2) is It is added intermittently, and the total amount added is calculated as Fe. Reactor volume.

[0017] Preferably, the hydraulic retention time of the microaerobic granular sludge reactor in step (2) is: The median particle size is sludge concentration is .

[0018] Preferably, the threshold in step (3) is: anaerobic effluent or .

[0019] Preferably, the microaerobic granular sludge reactor contains functional microbial communities; the functional microbial communities include ammonia-oxidizing bacteria, anaerobic ammonia-oxidizing bacteria, iron-oxidizing bacteria, iron-reducing bacteria, or co-metabolizing bacteria with aromatic amine degradation capabilities.

[0020] Preferably, the temperature of the microaerobic granular sludge reactor in step (2) is... pH is .

[0021] Preferably, the COD of the high carbon-to-nitrogen ratio dyeing wastewater in step (1) is: Total nitrogen is chromaticity is The total nitrogen in the effluent described in step (3) is ≤ times; , Color intensity ≤ 50 times.

[0022] Preferably, the anaerobic section uses an EGSB reactor, and the operating temperature is... , .

[0023] Preferably, the hydraulic retention time of the micro-oxygen section is: Median particle size of granular sludge , .

[0024] Preferably, the iron salt is added in an intermittent pulse manner, and the addition frequency is dynamically adjusted according to the Fe(II) concentration in the effluent or the activation efficiency of iron oxides.

[0025] The system finally discharged water , Color intensity ≤ 50 times, methane yield .

[0026] The present invention also provides an intelligent coupling system for implementing the above method, including an anaerobic reactor, a micro-aerobic reactor, an online water quality monitoring unit, a PLC control system, and an adjustable reflux device, to realize full-process parameter visualization and automated control.

[0027] Preferably, the system includes: (1) a high-efficiency anaerobic granular sludge reactor, equipped with an inlet, a biogas collection device, a sludge concentration monitor and an HRT adjustable device;

[0028] (2) Micro-aerobic granular sludge reactor, connected to the outlet of anaerobic reactor, and equipped with micro-aerobic granular sludge, micro-aerobic aeration device, iron salt dosing device and dissolved oxygen online monitoring instrument.

[0029] (3) Intelligent reflux system, including reflux pipeline, reflux pump and PLC controller, can automatically adjust the reflux ratio according to the anaerobic effluent water quality.

[0030] The beneficial effects of this invention are:

[0031] (1) A new two-stage synergistic process of "anaerobic decolorization and methanogenesis-micro-oxygen iron cycle denitrification co-metabolism" is proposed, which is in line with the transformation law of pollutants in dyeing and printing wastewater;

[0032] (2) The sludge activity is maintained by periodically adjusting the HRT of the anaerobic section, and the system robustness is enhanced by the reflux mechanism to cope with water quality fluctuations.

[0033] (3) Innovatively utilize the fluctuation of organic matter concentration in the micro-oxygen zone to regulate iron cycling activity, break through the passivation bottleneck of iron oxides, and simultaneously enhance denitrification and aromatic amine degradation;

[0034] (4) It has high process integration, low energy consumption, less sludge, and good resource recovery effect, and is suitable for green treatment and reuse of dyeing and printing wastewater with high carbon-nitrogen ratio.

[0035] Compared with existing technologies, the two-stage coupled granular sludge process provided by this invention has significant advantages in terms of technical performance, resource recovery, and operational stability compared with the traditional "hydrolysis acidification + aerobic activated sludge" process. A detailed comparison is shown in the table below:

[0036] Table 1. Technical Comparison between Anaerobic Granular Sludge + Micro-oxygen Iron Circulating Granular Sludge and Traditional Processes

[0037] Attached Figure Description

[0038] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0039] Figure 1 The process and control flow charts for a two-stage coupling system provided in some embodiments of this application are shown. Detailed Implementation

[0040] like Figure 1 As shown, this system includes a high-efficiency anaerobic granular sludge reactor, a microaerobic granular sludge reactor, a PLC controller, and a reflux actuator. After treatment in the anaerobic stage, the dyeing and printing wastewater enters the microaerobic stage; part of the effluent from the microaerobic stage is refluxed back to the anaerobic inlet, forming a load buffer and water quality regulation loop.

[0041] Example

[0042] Treatment of wastewater from a dyeing and printing factory, initial water quality: , , 600 times the color intensity .

[0043] Operating instructions:

[0044] (1) The HRT in the anaerobic section is adjusted every 5 days, and the adjustment range is as follows: This is to maintain sludge activity and adapt to influent fluctuations.

[0045] (2) When the COD of the anaerobic effluent is continuously monitored At that time, the PLC automatically starts the reflux pump, returning 30% of the micro-aerobic effluent to the anaerobic influent, approximately... The water quality returned to stable after an hour.

[0046] (3) The micro-aerobic zone is affected by fluctuations in influent COD ( It promotes changes in dissolved oxygen penetration depth inside granular sludge, and increases the activation efficiency of iron oxides by about 40%.

[0047] (4) The system in , Operating at low speed, it requires no external carbon source throughout the process, and the sludge yield is only a fraction of that of traditional aerobic processes. .

[0048] The process operating parameters and treatment effects are shown in Table 2:

[0049] Table 2 Operating parameters and processing effects of the two-stage coupled system

[0050]

[0051] To further illustrate the technical advantages of this invention, the treatment effects in the above specific embodiments are compared with those of the "traditional hydrolysis acidification + aerobic activated sludge" process operating under the same influent water quality conditions. The key indicators are compared in Table 3 below:

[0052] Table 3 Comparison of treatment effects between anaerobic granular sludge + micro-oxygen iron circulating granular sludge and traditional processes

[0053]

[0054] The above embodiments demonstrate that the system of the present invention exhibits excellent comprehensive performance in the treatment of dyeing and printing wastewater with a high carbon-to-nitrogen ratio, achieving " "It is integrated and has good anti-disturbance capabilities, making it suitable for engineering applications."

[0055] The above description is only a preferred embodiment of the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for treating high carbon-to-nitrogen ratio dyeing and printing wastewater using a two-stage coupled granular sludge system, characterized in that, Includes the following steps: (1) High carbon-to-nitrogen ratio dyeing and printing wastewater is fed into a high-efficiency anaerobic granular sludge reactor, and the anaerobic effluent is discharged. The hydraulic retention time is controlled to be [missing information]. sludge concentration is and every Adjust the HRT once a day; (2) Anaerobic effluent enters the microaerobic granular sludge reactor, and the concentration of organic matter in the influent is controlled at [value missing]. Dissolved oxygen concentration is And add iron salts; (3) When the HRT adjustment in the anaerobic section causes the effluent organic matter concentration to momentarily exceed the set threshold, the reflux control mechanism is activated to reflux a portion of the effluent from the microaerobic section to the influent from the anaerobic section, with a reflux ratio of [missing value]. .

2. The method according to claim 1, characterized in that, The HRT adjustment range of the high-efficiency anaerobic granular sludge reactor in step (1) is as follows: .

3. The method according to claim 1, characterized in that, The iron salt mentioned in step (2) is It is added intermittently, and the total amount added is calculated as Fe. Reactor volume.

4. The method according to claim 1, characterized in that, The hydraulic retention time of the microaerobic granular sludge reactor in step (2) is: The median particle size is sludge concentration is .

5. The method according to claim 1, characterized in that, The threshold mentioned in step (3): anaerobic effluent or .

6. The method according to claim 1, characterized in that, The microaerobic granular sludge reactor contains functional microbial communities; these functional microbial communities include ammonia-oxidizing bacteria, anaerobic ammonia-oxidizing bacteria, iron-oxidizing bacteria, iron-reducing bacteria, or co-metabolizing bacteria with aromatic amine degradation capabilities.

7. The method according to claim 1, characterized in that, The temperature of the microaerobic granular sludge reactor in step (2) is pH is .

8. The method according to claim 1, characterized in that, The COD of the high carbon-to-nitrogen ratio dyeing and printing wastewater mentioned in step (1) is: Total nitrogen is chromaticity is The total nitrogen in the effluent described in step (3) is times that of the previous step. , chromaticity times.

9. A system for implementing the method according to any one of claims 1-8, characterized in that, include: (1) A high-efficiency anaerobic granular sludge reactor is equipped with an inlet, a biogas collection device, a sludge concentration monitor and an HRT adjustable device; (2) Micro-aerobic granular sludge reactor, connected to the outlet of anaerobic reactor, and equipped with micro-aerobic granular sludge, micro-aerobic aeration device, iron salt dosing device and dissolved oxygen online monitoring instrument. (3) Intelligent reflux system, including reflux pipeline, reflux pump and PLC controller, can automatically adjust the reflux ratio according to the anaerobic effluent water quality.

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