An intelligent and efficient composite biological filter bed wastewater reuse process and system

Abstract

The present invention belongs to the technical field of wastewater recycling, and mainly relates to an intelligent and efficient composite biological filter bed wastewater reuse process and system, which includes the following steps: First, collect the waste gas generated by the waste gas source, and enter the bipolar high-efficiency cyclone hybrid spray tower through the traction force of the fan to quickly intercept and filter particulate matter; among them, control the environmental conditions of the waste gas treated by the spray tower, introduce it into the secondary packing spray absorption tower for washing and absorbing soluble components to pre-treat the waste gas; introduce the pre-treated waste gas into the biological filter bed air distribution and mixing zone, adjust the environmental conditions and then evenly introduce it into the composite biological packing zone, and the active microorganisms degrade the organic matter in the waste gas through biological enzymes and convert it into inorganic substances stored in the circulating water collection pool; and the inorganic substances are circulating water and carbon dioxide, and if the conductivity of the circulating water exceeds a certain value, it is diluted; finally, the circulating water is stored in the circulating water collection pool after secondary and tertiary purification through the advanced oxidation absorption tower and the demisting absorption tower, solving the defects of the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater recycling, and particularly relates to an intelligent and efficient composite biological filter bed wastewater reuse process and system. Background Art

[0002] Volatile organic compounds (VOCs), as pollutants widely existing in industrial production, are usually discharged into industrial waste gases, which pose great harm to the environment and human health. Although traditional treatment methods such as activated carbon adsorption and catalytic combustion can partially remove VOCs, they have deficiencies such as high treatment costs, easy generation of secondary pollution, and poor operation stability. In contrast, biological filter bed technology has been widely used in the treatment of VOCs waste gases in the industrial field due to its advantages of high-efficiency removal of organic waste gas pollutants, low investment and operation costs, and environmental friendliness.

[0003] In the specific implementation process, the biological filter bed uses the active microorganisms attached to the surface of the composite filler, takes the VOCs in the waste gas as the carbon source and energy source, and in an aerobic environment, uses the highly efficient catalytic bioenzymes secreted by its own metabolism to degrade the organic pollutants in the waste gas into harmless simple inorganic substances such as water and carbon dioxide, thereby achieving pollution treatment. Although the existing biological filter bed technology has the above advantages, in practical applications, the recycled water formed after the waste gas is treated by the biological filter bed often accumulates dissolved salts in the water during long-term recycling, resulting in an increase in conductivity; when the conductivity exceeds 10000 μS / cm, it will significantly inhibit the metabolic activity of microorganisms, causing the system treatment efficiency to drop by more than 30%; the long-term recycled wastewater is likely to cause the sludge concentration to exceed 5 g / L, and the sludge accumulation will block the filler pores in the biological filter bed, reducing the oxygen mass transfer efficiency.

[0004] Based on this, it is urgent to improve the existing biological filter bed wastewater reuse process and system to solve many technical defects in the existing technology. Summary of the Invention

[0005] One of the purposes of the present invention is to provide an intelligent and efficient composite biological filter bed wastewater reuse process that can solve the technical defect of the decreasing system treatment efficiency in view of the deficiencies of the existing technology.

[0006] In order to achieve the above invention purpose, the following technical solutions are implemented in this application:

[0007] An intelligent and efficient composite biological filter bed wastewater reuse process includes the following steps:

[0008] S101. The VOCs waste gas generated from the waste gas source is collected through the pipeline network and enters the first-stage bipolar high-efficiency cyclone hybrid spray tower tangentially under the traction of the fan. The VOCs waste gas quickly intercepts and filters the particulate matter under the action of the bipolar high-efficiency cyclone hybrid spray tower;

[0009] S201. Control the environmental conditions of the VOCs waste gas treated by the bipolar high-efficiency cyclone hybrid spray tower, and introduce the VOCs waste gas into the secondary packing spray absorption tower to wash and absorb the soluble VOCs components in the VOCs waste gas, thereby completing the pretreatment of the VOCs waste gas;

[0010] S301. Introduce the pretreated VOCs waste gas into the air distribution and mixed flow area at the front stage of the biological filter bed. Adjust the environmental conditions of the pretreated VOCs waste gas through the air distribution and mixed flow area and uniformly introduce the adjusted VOCs waste gas into the composite biological packing area at the rear stage of the biological filter bed. The active microorganisms attached to the composite biological packing area degrade the organic matter in the VOCs waste gas through highly catalytic biological enzymes, thereby converting it into inorganic substances and storing them in the circulating water collection pool;

[0011] S401. The inorganic substances are circulating water and carbon dioxide. When the conductivity of the circulating water in the circulating water collection pool exceeds 10000 μs / cm, dilute the circulating water to make the conductivity of the circulating water lower than 10000 μs / cm;

[0012] S501. The circulating water is secondarily purified through the coupled deep oxidation absorption tower and tertiary purified through the demisting absorber and then stored again in the circulating water collection pool;

[0013] The microbial growth kinetics equation introduced in step S401 is:

[0014]

[0015] In the above equation, X is the microbial concentration (g / L); S is the COD concentration (mg / L); DO is the dissolved oxygen (mg / L); is the TDS concentration corresponding to the conductivity (converted from μS / cm to mg / L or an equivalent ratio value); in the equation parameters such as are calibrated through bench-scale or pilot-scale tests, reflecting the actual growth of microorganisms under different COD, dissolved oxygen, and TDS conditions. In the model reflects the inhibitory effect of conductivity on the growth of microorganisms;

[0016] When the on-line monitored conductivity rises to a certain threshold, through the model the degree of inhibition can be quantitatively judged, so as to determine the amount of fresh water to be supplemented to dilute the TDS back to the range of 8000 - 10000 μS / cm.

[0017] As a further improvement of an intelligent and efficient composite biological filter bed wastewater reuse process of the present application, the composite biological packing area contains at least one of ceramsite, volcanic rock, PP balls, bamboo charcoal, and sponge.

[0018] As a further improvement of an intelligent and efficient composite biological filter bed wastewater reuse process in this application, the environmental conditions in step S301 include the temperature and humidity of the VOCs waste gas. A humidity sensor is provided in the uniform air mixing zone, and the humidity sensor continuously monitors the relative humidity of the VOCs waste gas introduced into the uniform air mixing zone.

[0019] When the relative humidity of the VOCs waste gas is lower than the set value, the spray circulating water is automatically turned on in the uniform air mixing zone.

[0020] When the relative humidity of the VOCs waste gas is greater than or equal to the set value, the spray volume in the uniform air mixing zone is automatically reduced or stopped.

[0021] The above technical solution has the following technical effects:

[0022] The technical solution of this application has realized the real-time automatic control and optimization of conductivity, sludge concentration and multiple variables in the VOCs waste gas treatment and wastewater recycling process for the first time. Through the systematic optimization of four key links: waste gas pretreatment, intelligent regulation of biological filter bed, dynamic regulation of conductivity and deep purification of circulating water, it effectively solves the long-term technical defects existing in the existing biological filter bed treatment technology in terms of conductivity accumulation, sludge concentration out of control and water quality fluctuation, ensuring that the treatment efficiency is stably above 90% for a long time, and the conductivity fluctuation is stable within the range of ±500 μS / cm, greatly reducing the operation cost and the risk of secondary pollution.

[0023] As a further improvement of an intelligent and efficient composite biological filter bed wastewater reuse process in this application, spray nozzles or atomizing nozzles are provided in the uniform air mixing zone, and the humidity is increased by quantitatively spraying circulating water into the uniform air mixing zone. The value range of the set value is: 60%RH - 80%RH.

[0024] As a further improvement of an intelligent and efficient composite biological filter bed wastewater reuse process in this application, a temperature sensor is provided in the uniform air mixing zone. When the temperature of the VOCs waste gas in the uniform air mixing zone is not within 10°C - 42°C, the temperature of the VOCs waste gas is adjusted.

[0025] As a further improvement of an intelligent and efficient composite biological filter bed wastewater reuse process in this application, in step S101, the VOCs waste gas enters the bipolar high-efficiency cyclone hybrid spray tower tangentially, and the VOCs waste gas combines with the spray liquid in the bipolar high-efficiency cyclone hybrid spray tower under the action of centrifugal force to quickly intercept and filter the particulate matter.

[0026] Among them, the particulate matter is one or more of fluff, grease, and dust.

[0027] As a further improvement to the intelligent and efficient composite biological filter bed wastewater reuse process of the present application, the advanced oxidation absorption tower uses UV / O3 synergistic oxidation;

[0028] Among them, the ozone dosage is 50mg / L - 100mg / L, and the ultraviolet wavelength is 254nm.

[0029] As a further improvement to the intelligent and efficient composite biological filter bed wastewater reuse process of the present application, the environmental conditions in steps S201 and S301 both involve the pH value of the VOCs waste gas;

[0030] When the pH value of the VOCs waste gas does not meet the range of 6.5 - 7.5, the pH value of the VOCs waste gas is adjusted by controlling the dosing system to meet the range of 6.5 - 7.5.

[0031] As a further improvement to the intelligent and efficient composite biological filter bed wastewater reuse process of the present application, the biological filter bed includes a microbial environment support system, and the microbial environment support system monitors and adjusts the water quality indicators of the active microorganisms attached to the composite biological filler area in the biological filter bed.

[0032] To achieve the above invention purposes, the present application has implemented the following technical solutions:

[0033] An intelligent and efficient composite biological filter bed wastewater reuse system includes the intelligent and efficient composite biological filter bed wastewater reuse process as described in any one of the above.

[0034] The above technical solutions have produced the following technical effects:

[0035] This system realizes precise control over the entire process of VOCs waste gas treatment. The intelligent regulation module can automatically adjust the operating parameters of key links such as waste gas pretreatment, biological filter bed environmental conditions, and circulating water purification according to real-time monitoring data, ensuring that the system is always in the optimal operating state. In addition, this system also has a fault warning and self-repair function. Once an abnormal situation occurs, the system can quickly respond and take measures, effectively avoiding problems such as a decrease in treatment efficiency or system shutdown caused by faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings described herein are used to provide a further understanding of the present invention, form a part of the present invention, and the schematic embodiments and descriptions thereof are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0037] Figure 1 It is a flowchart of the intelligent and efficient composite biological filter bed wastewater reuse process in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0038] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing specific embodiments, and are not intended to limit the present application.

[0039] In the description of the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0040] Although the present application is disclosed above in preferred embodiments, it is not used to limit the claims. Any person skilled in the art can make several possible changes and modifications without departing from the concept of the present application. Therefore, the protection scope of the present application should be determined by the scope defined by the claims of the present application.

[0041] The known biological filter bed technology takes into account that the active microorganisms attached to the porous and moist medium use the organic matter in the waste gas as the energy and nutrients for their life activities, grow, reproduce, and expand the population. During this process, a large amount of biological enzyme catalysts are produced. The microorganisms rely on the highly catalytic active biological enzymes they produce to degrade the organic matter. Thus, it is transformed into simple inorganic substances, such as CO2, H2O or cell composition substances.

[0042] The organic matter in the waste gas first undergoes a mass transfer process from the gas phase to the liquid phase, and then the organic components dissolved in the liquid phase further diffuse to the biofilm around the medium under the driving force of the concentration difference and are then captured and absorbed by the microorganisms therein. Under these conditions, the pollutants entering the microorganisms are decomposed as energy and nutrients during their own metabolic processes. Part of the metabolites dissolve in the liquid phase, part are used as cell substances or cell metabolic energy, and part, such as CO2, is released into the air. The organic matter in the waste gas is continuously reduced through the above process and thus purified.

[0043] However, volatile organic compounds (VOCs), as pollutants widely present in industrial production, are usually emitted in industrial waste gases and pose great hazards to the environment and human health. Although traditional treatment methods such as activated carbon adsorption and catalytic combustion can partially remove VOCs, they have deficiencies such as high treatment costs, easy generation of secondary pollution, and poor operation stability. In contrast, biofilter technology has been widely used in the treatment of VOC waste gases in the industrial field due to its advantages of efficient removal of organic waste gas pollutants, low investment and operation costs, and environmental friendliness.

[0044] In a biofilter, the active microorganisms attached to the surface of composite fillers (such as porous materials like ceramsite, volcanic rock, and bamboo charcoal) use the VOCs in the waste gas as a carbon source and energy source. In an aerobic environment, they utilize the highly efficient catalytic bioenzymes secreted by their own metabolism to degrade the organic pollutants in the waste gas into harmless water (circulating water) and simple inorganic substances such as carbon dioxide, thus achieving pollution control. Moreover, as national and regional environmental protection policies become stricter, industrial enterprises are urgently in need of a highly efficient, economical, and stable VOC treatment technology. Biofilter technology not only has outstanding economy but also can operate stably for a long time without generating secondary pollutants, and is suitable for long-term application in industries such as PCB manufacturing, electronics manufacturing, coating production, chemical manufacturing, and lithium battery production. Therefore, this technology has been recognized and promoted by more and more industries.

[0045] Furthermore, although the existing biofilter technology has the above advantages, in practical applications, the circulating water formed after the waste gas is treated by the biofilter often exposes the following prominent technical problems during the long-term recycling process:

[0046] 1) Severe accumulation effect of circulating water conductivity: With the repeated use of circulating water, the dissolved salts in the water gradually accumulate, resulting in an increase in conductivity; when the conductivity exceeds 10000 μS / cm, it will significantly inhibit the metabolic activity of microorganisms, causing the system treatment efficiency to decrease by more than 30%.

[0047] 2) Out-of-control sludge concentration and low oxygen mass transfer efficiency: The wastewater in long-term circulation is likely to cause the sludge concentration to exceed 5 g / L. The accumulation of sludge will block the voids of the filler and reduce the oxygen mass transfer efficiency;

[0048] In addition, the formation of local anoxic regions will produce anaerobic metabolism and release malodorous pollutants such as H2S, reducing the purification efficiency;

[0049] 3) Difficulty in multi-variable dynamic regulation: There is a strong coupling relationship among conductivity, COD, pH, and DO. Traditional manual or simple control methods cannot achieve real-time and efficient coordination; the system parameters cannot be accurately controlled, and the fluctuation range of the circulating water volume is relatively large (±25%), making it difficult to meet the requirements for the long-term stable operation of the biofilter.

[0050] In summary, the key problems that the existing biological filter bed technology urgently needs to solve are the difficult precise control of the circulating water conductivity, the too high sludge concentration, and the difficult real-time coordination and optimization of multiple variables.

[0051] To solve the above technical defects, this application has made improvements to the biological filter bed wastewater reuse process. Specifically, the intelligent and efficient composite biological filter bed wastewater reuse process of this application includes the following steps:

[0052] S101. The VOCs waste gas generated by the waste gas source is collected through the pipe network and enters the first-stage bipolar high-efficiency cyclone hybrid spray tower tangentially under the traction of the fan. The VOCs waste gas quickly intercepts and filters the particulate matter under the action of the bipolar high-efficiency cyclone hybrid spray tower.

[0053] S201. Control the environmental conditions of the VOCs waste gas treated by the bipolar high-efficiency cyclone hybrid spray tower, and introduce the VOCs waste gas into the secondary packing spray absorption tower to wash and absorb the soluble VOCs components in the VOCs waste gas, thereby completing the pretreatment of the VOCs waste gas.

[0054] S301. Introduce the pretreated VOCs waste gas into the air distribution and mixing area at the front section of the biological filter bed. Through the air distribution and mixing area, adjust the environmental conditions of the pretreated VOCs waste gas and evenly introduce the adjusted VOCs waste gas into the composite biological packing area at the rear section of the biological filter bed. The active microorganisms attached to the composite biological packing area degrade the organic matter in the VOCs waste gas through highly catalytic biological enzymes, thereby converting it into inorganic substances and storing them in the circulating water collection pool.

[0055] S401. The inorganic substances are circulating water and carbon dioxide. When the conductivity of the circulating water in the circulating water collection pool exceeds 10000 μs / cm, dilute the circulating water to make the conductivity of the circulating water lower than 10000 μs / cm.

[0056] S501. The circulating water undergoes secondary purification through the coupled deep oxidation absorption tower and tertiary purification through the demisting absorber and is stored again in the circulating water collection pool.

[0057] In the above technical solution, the circulating water collection pool adopted in this application is equipped with an on-line conductivity sensor (its detection range is: 0~20000 μS / cm) for real-time monitoring; when the circulating water conductivity exceeds the set threshold (10000 μS / cm), the make-up water control valve is automatically opened, and fresh water is dynamically added to dilute the conductivity back to the safe range; prevent the conductivity from exceeding the microbial tolerance value, ensure the long-term stable activity of microorganisms, and maintain the high-efficiency treatment ability.

[0058] In addition, the present application also considers that the main pollutants causing secondary pollution in the circulating water are a small amount of wastewater and sludge. The wastewater generated per 10,000 m³ of exhaust gas per month is 1 m³, and the sludge is 5 L. The circulating water in the circulating water tank contains the conductivity and sludge accumulated during operation. High conductivity will affect the metabolic activity of microorganisms, and too high sludge concentration will also lead to an increase in the oxygen consumption rate, easily resulting in insufficient dissolved oxygen and hypoxia, thereby affecting the growth and reproduction of microorganisms. Therefore, when the water conductivity > 10,000 μS / cm and the biological sludge concentration > 5 g / L, it is necessary to automatically control drainage and sludge discharge to ensure that the microorganisms are in the best growth environment and continuously and efficiently purify VOCs exhaust gas stably. If the external discharge of wastewater or sludge from the system is restricted, it can be coupled with the waste (medium) water system and discharged to the temporary storage tank for on-site treatment through the AO process to further reduce COD (sludge). After treatment, part of it is recycled to further reduce the external discharge volume.

[0059] Furthermore, the composite biological filler area contains at least one of ceramsite, volcanic rock, PP balls, bamboo charcoal, and sponge. The porosity of ceramsite is 40%, with low density and moderate mechanical strength;

[0060] Volcanic rock has a large surface area, is easy to form a biofilm, and is light in texture; bamboo charcoal has a high adsorption capacity and has a preliminary adsorption buffering effect on a variety of refractory organic substances. Thus, the composite biological filler area provides a rich surface for microbial attachment and a suitable microbial growth environment by combining the advantages of the above different materials. The porous structures of materials such as ceramsite and volcanic rock contribute to the attachment and growth of microorganisms, and at the same time provide good oxygen mass transfer channels to ensure the oxygen demand of microorganisms during the degradation of organic substances. Materials such as PP balls and sponge have good water flow distribution performance, which helps the exhaust gas to fully contact with the circulating water and improves the degradation efficiency of organic substances.

[0061] Furthermore, based on the traditional Monod kinetics, this technology introduces a conductivity (TDS) inhibition factor and a multi-objective optimization mechanism.

[0062] Among them, the microbial growth kinetic equation is:

[0063]

[0064] In the above equation, X is the microbial concentration (g / L); S is the COD concentration (mg / L); DO is the dissolved oxygen (mg / L); is the TDS concentration corresponding to the conductivity (converted from μS / cm to mg / L or an equivalent proportional value); in the equation parameters such as are calibrated through bench-scale or pilot-scale tests, reflecting the actual growth conditions of microorganisms under different COD, dissolved oxygen, and TDS conditions. In the model, reflects the inhibitory effect of conductivity on microbial growth;

[0065] When the on-line monitored conductivity increases to a certain threshold, through the model the inhibition degree can be quantitatively judged, so as to determine the amount of fresh water to be supplemented, so as to dilute the TDS back to the range of 8000-10000 μS / cm.

[0066] During the engineering design, according to this model, the biomass growth rate and substrate removal amount can be estimated, so as to reasonably determine the key parameters such as the height of the biological filter bed packing, the residence time and the spraying load, etc., and avoid investment waste or insufficient treatment efficiency caused by blind design.

[0067] In the model reflects the inhibitory effect of salinity (conductivity) on the growth of microorganisms. When the on-line monitored conductivity increases to a certain threshold, the inhibition degree can be quantitatively judged through this item, so as to determine the amount of fresh water to be supplemented, so as to dilute the TDS back to the acceptable range (such as 8000-10000 μS / cm), protect the microbial activity and maintain the treatment efficiency. At the same time, it should be noted that the above model is the setting mechanism for determining the conductivity threshold of 10000 μS / cm in this application. When the conductivity inhibition tendency is detected, fresh water can be supplemented in time for dilution to ensure that the circulating water conductivity is within a narrow fluctuation range (such as ±500 μS / cm), thereby improving the availability and safety of the circulating water; at the same time, reducing the direct discharge amount of wastewater, and realizing water saving, emission reduction and green production.

[0068] It should be noted that once the model parameters are determined through bench-scale / pilot-scale tests, this model can be reused or quickly calibrated to a certain extent in different industries (such as PCB, chemical industry, lithium battery, etc.); and it can be combined with the SCADA / DCS system to realize continuous automatic monitoring, which is convenient for remote or unattended operation management.

[0069] Furthermore, the bipolar high-efficiency cyclone hybrid spray tower mentioned in this application is mainly used to remove large particles, grease and fluff in the VOCs waste gas, and at the same time preliminarily adjust the pH, temperature and humidity of the gas. When the waste gas enters the spray tower tangentially, the combination of centrifugal force (centrifugal acceleration ≥5g) and the impact of the spray liquid is used to improve the impurity removal efficiency; at the same time, reagents such as NaOH / HCl are added to the spray tower to control the gas pH, so as to maintain the appropriate range required by microorganisms; and the pretreatment can reduce the burden of the subsequent biological filter bed.

[0070] Among them, the secondary packing spray absorption tower is mainly used to absorb soluble VOCs components and stabilize the concentration and humidity of the waste gas. It uses PP or PVC packing (specific surface area ≥ 300 m² / m³), and utilizes the spray liquid with surfactants or absorbents to absorb soluble or partially polar VOCs; most of the soluble pollutants in the pretreated gas have been captured, which can significantly reduce the load fluctuation of the biological filter bed.

[0071] Furthermore, the biological filter bed mentioned in this application is mainly divided into two sections: a uniform mixed-flow area and a composite biological packing area. Among them, in the uniform mixed-flow area, porous flow guiding plates (opening ratio 30% - 50%) or grid-shaped flow equalizing devices are used to ensure uniform distribution of the waste gas before entering the biological filter layer; temperature, humidity, and pH sensors are installed inside to monitor the microenvironment in real time. Through the setting of the sensors, the waste gas flow rate, temperature, humidity, and pH are made more uniform, avoiding local overload of microorganisms; thus, concentration fluctuations (such as intermittent emissions) are suppressed, making the back-end biological filter area more stable. The composition of the packing in the composite biological packing area will not be elaborated here.

[0072] Furthermore, for waste gas with extremely high treatment requirements or containing a small amount of hardly biodegradable components, this solution can be optionally equipped with a deep oxidation absorption tower and a demisting absorber to achieve secondary or tertiary enhanced purification. Among them, the deep oxidation absorption tower uses UV / O3 synergistic oxidation, with an ozone dosage of 50 - 100 mg / L and an ultraviolet wavelength of 254 nm; for some hardly degradable components (such as benzene series, aldehydes and ketones, etc.), they can be further oxidized into easily biodegradable or low-toxicity intermediate products; the treatment efficiency is increased to ≥ 95%. The demisting absorber can intercept aerosol fine mists and trace residual VOCs;

[0073] The non-methane total hydrocarbons at its outlet can be stabilized at ≤ 10 mg / m³, meeting more stringent environmental protection standards.

[0074] In addition, this application also adopts an intelligent control system, which can monitor the environmental conditions (such as temperature, humidity, pH value, etc.) inside the biological filter bed and the water quality parameters of the circulating water (such as conductivity, COD, etc.) in real time. According to the monitoring data, the intelligent control system can automatically adjust parameters such as the spray volume, makeup water volume, and drainage volume to keep the environmental conditions inside the biological filter bed in the optimal state, while ensuring that the water quality of the circulating water meets the growth requirements of microorganisms. This intelligent regulation method not only improves the treatment efficiency of the system, but also reduces the operation cost and maintenance difficulty.

[0075] In summary, the intelligent and efficient composite biofilter wastewater reuse process and system provided by this application achieve precise control over the entire process of VOCs waste gas treatment by accurately controlling the operating parameters of key links such as waste gas pretreatment, biofilter environmental conditions, and circulating water purification. This system not only has the ability to efficiently remove organic waste gas pollutants, but also has advantages such as low investment and operating costs and environmental friendliness, and is applicable to multiple industries such as PCB manufacturing, electronic manufacturing, coating production, chemical manufacturing, and lithium battery production.

[0076] The following further describes the present invention in detail in conjunction with specific embodiments, but the embodiments of the present invention are not limited thereto.

[0077] Example 1

[0078] Background:

[0079] Waste gas flow rate: 100,000 m³ / h; the main VOCs are benzene, toluene, and alcohols;

[0080] Drainage volume of the biofilter spray liquid crystal: about 50 m³ / d;

[0081] Initial COD of the wastewater: 320 mg / L, conductivity: 10500 μS / cm, sludge concentration: 6.8 g / L.

[0082] Process:

[0083] Pretreatment: bipolar cyclone spray tower + secondary packing tower to remove dust and most soluble VOCs;

[0084] Biofilter: packing thickness 1.5 m, composite packing ratio: ceramsite∶volcanic rock∶bamboo charcoal = 3∶2∶1 (volume ratio);

[0085] Wastewater reuse:

[0086] Gradient flocculation and precipitation: add PAC (50 mg / L) + PAM (0.5 mg / L), control the sedimentation flow rate at 0.2 m / s;

[0087] Supplement fresh water Q according to the formula Control the conductivity at 8500±500 μS / cm; adjust the carbon source and aeration volume through fuzzy PID to maintain COD at 180±20 mg / L and pH = 7.0±0.3.

[0088] Thus, in this embodiment, the fluctuation is reduced from ±1500 μS / cm in the traditional process to ±500 μS / cm; the COD removal rate reaches an average of 93%, a 24% increase compared to about 75% in the traditional process; the sludge production rate is reduced from 8 g / L to 4.5 g / L, a 43.75% reduction; the operation and maintenance cost is about 0.5 yuan per cubic meter, significantly lower than 1.8 yuan per cubic meter of the activated carbon adsorption system.

[0089] Example 2

[0090] Background:

[0091] This embodiment is mainly applied to the waste gas and high-humidity occasions in the lithium battery industry. The waste gas to be treated contains alcohol solvents and has a high humidity (≥80%RH);

[0092] The operating temperature of the biological filter bed is 25 - 35°C, and the conductivity is easily accumulated to more than 12000 μS / cm.

[0093] When the conductivity of the circulating water is about to break through 12000 μS / cm, start the reverse osmosis concentration and discharge 10% to reduce the salt accumulation; the remaining 90% of the circulating water is maintained in the range of 8000 - 10000 μS / cm; in addition, this embodiment adds a section of aeration to remove CO2 to optimize the pH of the circulating water between 6.5 - 7.5.

[0094] In summary, the treatment efficiency of the system in this embodiment is stable at 89% - 93%, and the microorganisms still maintain good activity under high-humidity conditions; by locally discharging salts and reverse osmosis desalination, the out-of-control of conductivity is avoided; the waste of water resources caused by simply supplementing large-flow fresh water is avoided.

[0095] For those that are the same as Embodiment 1, they will not be elaborated in this embodiment.

[0096] Example 3

[0097] Background:

[0098] This embodiment is applied under the conditions of multi-component VOCs (esters, ketones) in the chemical industry. There are various volatile and partially difficult-to-biodegrade organic substances (such as esters, ketones) in the waste gas;

[0099] When the biological filter bed degrades esters, it is easy to produce odors, and the residues of intermediate products may require post-treatment.

[0100] Process:

[0101] Add a UV / O3 advanced oxidation tower + demisting absorber at the rear end of the biological filter bed; use an intelligent control system to adjust the O3 dosage to ensure the oxidation efficiency; in addition, the corresponding wastewater reuse link adds activated carbon filtration (to reduce odors and local dissolved by-products).

[0102] Finally, the total removal rate of esters and ketones in this application is ≥95%; the organic load of the biological filter bed is stable at about 3.5 kgCOD / m³ packing·d, without obvious anaerobic blockage; the wastewater reuse rate can reach 80%, and only a small amount of fresh water needs to be supplemented (the makeup water volume <20%).

[0103] For those that are the same as those in Embodiment 1, they will not be repeated in this embodiment.

[0104] The above are only the preferred embodiments of this application and are not used to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. An intelligent and efficient composite biological filter bed wastewater reuse process, characterized in that It includes the following steps: S101. The VOCs waste gas generated by the waste gas source is collected through the pipe network and enters the bipolar high-efficiency cyclone hybrid spray tower tangentially under the traction of the fan. The VOCs waste gas quickly intercepts and filters the particulate matter under the action of the bipolar high-efficiency cyclone hybrid spray tower; S201. Control the environmental conditions of the VOCs waste gas treated by the bipolar high-efficiency cyclone hybrid spray tower, and introduce the VOCs waste gas into the secondary packing spray absorption tower to wash and absorb the soluble VOCs components in the VOCs waste gas, thereby completing the pretreatment of the VOCs waste gas; S301. Introduce the pretreated VOCs waste gas into the air distribution and mixing zone at the front stage of the biological filter bed. Adjust the environmental conditions of the pretreated VOCs waste gas through the air distribution and mixing zone and uniformly introduce the adjusted VOCs waste gas into the composite biological packing zone at the rear stage of the biological filter bed. The active microorganisms attached to the composite biological packing zone degrade the organic matter in the VOCs waste gas through highly catalytic biological enzymes, thereby converting it into inorganic substances and storing them in the circulating water collection pool; S401. The inorganic substances are circulating water and carbon dioxide. When the conductivity of the circulating water in the circulating water collection pool exceeds 10000 μs / cm, dilute the circulating water to make the conductivity of the circulating water lower than 10000 μs / cm; S501. The circulating water is secondarily purified through the coupled deep oxidation absorption tower and tertiary purified through the demisting absorber and then stored again in the circulating water collection pool; The microbial growth kinetics equation introduced in step S401 is: In the above equation, X is the microorganism concentration in g / L; S is the COD concentration in mg / L; DO is the dissolved oxygen in mg / L; is the TDS concentration corresponding to the conductivity, the conductivity unit is μS / cm, and the TDS concentration is in mg / L; in the equation the parameters are calibrated through bench-scale or pilot-scale tests, which reflect the actual growth of microorganisms under different COD, dissolved oxygen, and TDS conditions. In the model reflects the inhibitory effect of conductivity on the growth of microorganisms; When the conductivity of the on-line monitoring increases to a certain threshold, through the said model the degree of inhibition can be quantitatively judged, so as to determine the amount of fresh water to be supplemented, in order to dilute the TDS back to the range of 8000 - 10000 μS / cm.

2. The intelligent and efficient composite biological filter bed wastewater reuse process according to claim 1, characterized in that, The composite biological packing zone contains at least one of ceramsite, volcanic rock, PP balls, bamboo charcoal, and sponge.

3. An intelligent and efficient composite biological filter bed wastewater reuse process according to claim 1, characterized in that In step S301, the environmental conditions include the temperature and humidity of the VOCs waste gas. A humidity sensor is provided in the air distribution and mixing zone, and the humidity sensor real-time monitors the relative humidity of the VOCs waste gas introduced into the air distribution and mixing zone; When the relative humidity of the VOCs waste gas is lower than the set value, the spray circulating water is automatically turned on in the air distribution and mixing zone; When the relative humidity of the VOCs waste gas is greater than or equal to the set value, the spray amount in the air distribution and mixing zone is automatically reduced or stopped.

4. An intelligent and efficient composite biological filter bed wastewater reuse process according to claim 3, characterized in that, A spray nozzle or atomizing nozzle is provided in the air distribution and mixing zone, and the humidity is increased by quantitatively spraying circulating water into the air distribution and mixing zone. The value range of the set value is: 60%RH - 80%RH.

5. An intelligent and efficient composite biological filter bed wastewater reuse process according to claim 3, characterized in that A temperature sensor is provided in the air distribution and mixing zone. When the temperature of the VOCs waste gas in the air distribution and mixing zone is not within 10°C - 42°C, adjust the temperature of the VOCs waste gas.

6. The intelligent and efficient composite biological filter bed wastewater reuse process according to claim 1, characterized in that, In step S101, the VOCs waste gas enters the bipolar high-efficiency cyclone hybrid spray tower tangentially. The VOCs waste gas combines with the impact of the spray liquid in the bipolar high-efficiency cyclone hybrid spray tower under the action of centrifugal force, thereby quickly intercepting and filtering the particulate matter; Among them, the particulate matter is one or more of fluff, grease, and dust.

7. An intelligent and efficient composite biological filter bed wastewater reuse process according to claim 1, characterized in that The deep oxidation absorption tower uses UV / O3 for synergistic oxidation; Among them, the ozone dosage is 50 mg / L - 100 mg / L, and the ultraviolet wavelength is 254 nm.

8. An intelligent and efficient composite biological filter bed wastewater reuse process according to claim 1, characterized in that The environmental conditions in the step S201 and the step S301 both involve the pH value of the VOCs waste gas; When the pH value of the VOCs waste gas does not meet the range of 6.5 - 7.5, the pH value of the VOCs waste gas is adjusted by controlling the dosing system to meet the range of 6.5 - 7.

5.

9. An intelligent and efficient composite biological filter bed wastewater reuse process according to claim 1, characterized in that, The biological filter bed includes a microbial environment support system, and the microbial environment support system monitors and adjusts the water quality indexes of the active microorganisms attached to the composite biological filler area in the biological filter bed.

10. An intelligent and efficient composite biological filter bed wastewater reuse system, characterized in that It includes the intelligent and efficient composite biological filter bed wastewater reuse process according to any one of claims 1 - 9.

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