Treatment method of high-concentration wastewater

Abstract

The invention relates to a high-concentration wastewater treatment method, and relates to the technical field of wastewater treatment.The high-concentration wastewater treatment method comprises the following steps that high-concentration wastewater to be treated is subjected to coagulating sedimentation and then subjected to oxidation treatment, and first wastewater is obtained; sequentially carrying out first hydrolysis reaction treatment, first anaerobic reaction treatment and first aerobic reaction treatment on the first wastewater to obtain second wastewater; sequentially carrying out second hydrolysis reaction treatment, second anaerobic reaction treatment and second aerobic reaction treatment on the second wastewater to obtain third wastewater; carrying out denitrification reaction treatment on the third wastewater, then carrying out mud-water separation treatment and the like. According to the invention, a combined process of'coagulating sedimentation + persulfate advanced oxidation 'and'anaerobic + aerobic + anaerobic ammonia oxidation denitrification' is mainly adopted, so that the effluent quality of the high-concentration wastewater is stable and reaches the standard, and the problems of high operation cost, poor sewage treatment effect and the like in the prior art are effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a method for treating high-concentration wastewater. Background Art

[0002] With the rapid development of industrial production, the types and quantities of wastewater generated are also increasing. Among them, high-concentration wastewater is extremely difficult to treat due to its high chemical oxygen demand (COD>20000mg / L), high total nitrogen (>3000mg / L) and high salt (>5000mg / L) and other characteristics, which poses a serious threat to the environment. This type of wastewater is not only complex in composition, but also has high organic matter content, high nitrogen content and high salt content. It is often difficult to meet national emission standards by using only one traditional wastewater treatment process.

[0003] At present, there are two common combined treatment processes for the treatment of this type of high-concentration wastewater: 1. Anaerobic-aerobic-membrane treatment process: This process usually uses an upflow anaerobic sludge blanket (UASB) as the anaerobic treatment unit. Through the action of anaerobic microorganisms, most of the organic matter in the wastewater is converted into combustible gases such as methane, thereby achieving initial degradation of the organic matter.

[0004] Subsequently, a membrane bioreactor (MBR) is used as an aerobic treatment unit to further oxidize and decompose the remaining organic matter through aerobic microorganisms and remove part of the nitrogen.

[0005] Finally, deep purification is carried out through membrane treatment technologies such as reverse osmosis (RO) to ensure that the effluent quality meets the discharge standards.

[0006] However, this process has the problem of high investment cost, especially for the membrane treatment unit. The membrane is a high-cost consumable material and generally needs to be replaced every 3-5 years, and its investment proportion in the entire process is relatively large. In addition, the operation and maintenance of the membrane is relatively difficult, requiring professional technical and management personnel.

[0007] 2. Biological treatment + Fenton advanced oxidation + membrane treatment process: The process combines the advantages of biological treatment, advanced oxidation and membrane treatment. It first removes some organic matter and nitrogen from the wastewater through a biological treatment unit.

[0008] Then, Fenton advanced oxidation technology is used to utilize the strong oxidizing property of Fenton reagent to further oxidize and decompose the difficult-to-degrade organic matter in the wastewater, thereby improving the biodegradability of the wastewater.

[0009] Finally, membrane treatment technology is also used for deep purification to ensure that the effluent meets the standards.

[0010] However, this process also has the problem of high investment cost. Since the membrane treatment unit is used, the replacement cost of the membrane is high. At the same time, the operating cost of Fenton advanced oxidation is also relatively high, usually reaching 10 to 20 yuan per cubic meter of water, which increases the overall cost of wastewater treatment.

[0011] In summary, although the existing high-concentration wastewater treatment combined process can effectively remove various pollutants in wastewater to a certain extent, it generally has problems such as high investment cost, difficult operation and maintenance, and high operating cost. Therefore, it is urgent to develop a high-concentration wastewater treatment method with low investment cost, simple operation and maintenance, low operating cost and good treatment effect to meet the needs of actual production and environmental protection requirements. Summary of the invention

[0012] In order to solve the above problems, the present invention provides a method for treating high-concentration wastewater.

[0013] The technical solution provided by the present invention is as follows: The present invention provides a method for treating high-concentration wastewater, such as Figure 1 As shown, the method for treating high-concentration wastewater comprises the following steps: The high-concentration wastewater to be treated is subjected to coagulation and sedimentation, and then subjected to oxidation treatment to obtain the first wastewater; The first wastewater is sequentially subjected to a first hydrolysis reaction treatment, a first anaerobic reaction treatment and a first aerobic reaction treatment to obtain a second wastewater; The second wastewater is sequentially subjected to a second hydrolysis reaction treatment, a second anaerobic reaction treatment, and a second aerobic reaction treatment to obtain a third wastewater; The third wastewater is subjected to a denitrification reaction treatment, and then subjected to a mud-water separation treatment to obtain treated discharge water; The physical and chemical property parameters of the high-concentration wastewater to be treated include: chemical oxygen demand>20000mg / L, total nitrogen content>3000mg / L and salt content>5000mg / L; The oxidation treatment method is a persulfate advanced oxidation method; The first anaerobic reaction treatment and the second anaerobic reaction treatment are both carried out by using a folded plate anaerobic biological iron fluidized bed, wherein the folded plate anaerobic biological iron fluidized bed is a biological fluidized bed component added to the rear end of an anaerobic baffled reactor; The denitrification reaction treatment method is anaerobic ammonium oxidation.

[0014] Furthermore, the step of subjecting the high-concentration wastewater to be treated to coagulation and sedimentation, and then to oxidation treatment to obtain the first wastewater includes the following process: Passing the high-concentration wastewater to be treated into a regulating tank, and then passing it into a coagulation tank containing a coagulant, a flocculation tank containing a flocculant, and a persulfate oxidation tank containing persulfate in sequence for treatment to obtain the first wastewater; The operating conditions of the coagulation tank include: pH 8-12; temperature 25-27°C; time 0.5h; in terms of weight percentage, the added weight of the coagulant is 0.02% of the weight of the high-concentration wastewater to be treated, and the coagulant includes iron salt; The operating condition parameters of the flocculation tank include: pH 8-12; temperature 25-27°C; time 0.5h; in terms of weight percentage, the added weight of the flocculant is 0.006% of the weight of the high-concentration wastewater to be treated, and the flocculant includes polyacrylamide; The operating condition parameters of the persulfate oxidation tank include: pH 2-12; temperature 25-27°C; time 4h; in terms of weight percentage, the added weight of the persulfate is 0.16% of the weight of the high-concentration wastewater to be treated.

[0015] Furthermore, the step of sequentially subjecting the first wastewater to a first hydrolysis reaction treatment, a first anaerobic reaction treatment and a first aerobic reaction treatment to obtain the second wastewater comprises the following process: Passing the first wastewater into a primary hydrolysis fluidized bed, a primary folded plate anaerobic biological iron fluidized bed and a primary aerobic fluidized bed in sequence for treatment to obtain the second wastewater; The operating conditions of the primary hydrolysis fluidized bed include: dissolved oxygen <1 mg / L, pH 4-7, temperature 20-35°C, and time 40h; The operating condition parameters of the first-stage folded plate anaerobic biological iron fluidized bed include: dissolved oxygen <0.5 mg / L, pH 6-8, temperature 20-35°C, and time 46 hours; The operating condition parameters of the primary aerobic fluidized bed include: dissolved oxygen of 2-6 mg / L, pH of 6-8, temperature of 20-35° C., and time of 38 hours.

[0016] Further, the step of sequentially subjecting the second wastewater to a second hydrolysis reaction treatment, a second anaerobic reaction treatment, and a second aerobic reaction treatment to obtain the third wastewater comprises the following process: The second wastewater is passed into the intermediate water tank 1, and then passed into the secondary hydrolysis fluidized bed, the secondary folded plate anaerobic biological iron fluidized bed and the secondary aerobic fluidized bed in sequence for treatment to obtain the third wastewater; The operating condition parameters of the secondary hydrolysis fluidized bed and the primary hydrolysis fluidized bed are the same; The operating condition parameters of the secondary folded plate anaerobic biological iron fluidized bed and the primary folded plate anaerobic biological iron fluidized bed are the same; The operating condition parameters of the secondary aerobic fluidized bed and the primary aerobic fluidized bed are the same.

[0017] Furthermore, the step of subjecting the third wastewater to denitrification reaction treatment and then to mud-water separation treatment to obtain treated discharge water comprises the following process: The third wastewater is passed into the intermediate water tank 2, and then sequentially passed into the anaerobic ammonia oxidation tank for denitrification reaction and the final sedimentation tank for mud-water separation to obtain the discharge water; The operating conditions of the anaerobic ammonium oxidation tank include: dissolved oxygen <0.5 mg / L, pH 6-8, temperature 26-35°C, and time 8 hours; The operating conditions of the final sedimentation tank include: temperature of 25-27°C and time of 4 hours.

[0018] Furthermore, the method for treating high-concentration wastewater also includes: The sludge from the flocculation tank, the first-stage folded plate anaerobic biological iron fluidized bed, the second-stage folded plate anaerobic biological iron fluidized bed and the final sedimentation tank is collected in a sludge thickening tank and then subjected to filter pressing treatment through a sludge filter press.

[0019] Furthermore, the sludge in the primary aerobic fluidized bed and the secondary aerobic fluidized bed is returned to the primary hydrolysis fluidized bed and the secondary hydrolysis fluidized bed.

[0020] Furthermore, the supernatant of the sludge thickening tank and the filtrate of the sludge filter press are both returned to the regulating tank.

[0021] Furthermore, the physical and chemical property parameters of the treated discharge water include: chemical oxygen demand <10000 mg / L, total nitrogen content <600 mg / L and salt content <4800 mg / L.

[0022] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art: The present invention provides a method for treating high-concentration wastewater. The present invention mainly adopts "coagulation sedimentation + persulfate advanced oxidation" and then enters the "anaerobic + aerobic + anaerobic ammonia oxidation denitrification" combined process to ensure that the effluent water quality of high-concentration wastewater is stable and meets the standards, effectively solving the problems of high operating costs and poor sewage treatment effects in the prior art. Specifically: 1. The denitrification reaction treatment method adopts anaerobic ammonium oxidation method: 1) High efficiency denitrification capacity: The anaerobic ammonium oxidation process can directly convert ammonia nitrogen (NH4 + ) and nitrite nitrogen (NO2 -) is efficiently converted into nitrogen (N2), with extremely high denitrification efficiency, and the nitrogen removal rate can stably reach more than 85%. When treating high ammonia nitrogen wastewater, the volumetric nitrogen removal rate of this process is particularly outstanding, showing excellent treatment performance. 2) Low energy consumption and low carbon emissions: Compared with the traditional nitrification-denitrification process, the anaerobic ammonium oxidation process does not require a large amount of aeration, and the aeration energy consumption is only 55% to 60% of the traditional process, which significantly reduces energy consumption. This process is almost independent of external carbon sources. Even when carbon sources need to be added, the amount added is 90% less than that of traditional processes, effectively saving resources. The greenhouse gases (such as N2O) produced during the anaerobic ammonium oxidation process are less emitting, which is more environmentally friendly and helps to reduce the greenhouse effect. 3) Low operating cost: Due to low energy consumption and low carbon source demand, the operating cost of the anaerobic ammonium oxidation process is significantly lower than that of the traditional denitrification process, which brings significant economic benefits to wastewater treatment plants. In addition, the sludge output of this process is low, which reduces the treatment and disposal costs of excess sludge and further reduces the overall operating costs. 4) Small footprint: The anaerobic ammonium oxidation reactor is compact and has high treatment efficiency. Therefore, under the same treatment scale, its footprint is only 1 / 3 to 1 / 2 of the traditional process, which effectively saves land resources. 5) Environmental friendliness: The byproducts produced during the anaerobic ammonium oxidation process are mainly harmless nitrogen, which has no negative impact on the environment. The process can also reduce alkalinity consumption by 45%, reducing dependence on chemical agents, further demonstrating its environmentally friendly characteristics.

[0023] 2. Compared with the traditional Fenton oxidation, the oxidation treatment method of the present invention adopts the persulfate advanced oxidation method: 1) Oxidation ability: Persulfate oxidation method: By generating sulfate free radicals, although its redox potential is slightly lower than that of hydroxyl free radicals in Fenton oxidation (·OH, 2.6 V vs 2.8 V), the reaction life of sulfate free radicals is longer, and it can more effectively penetrate and degrade the complex structure of organic matter. 2) Fenton oxidation method: Relying on the strong oxidizing property of hydroxyl free radicals, the oxidation ability is very strong, but its life is short, the diffusion distance is limited, and the degradation efficiency of complex structure organic matter is relatively low. 3) Reaction conditions: Persulfate oxidation method: The reaction conditions are relatively mild, and it can operate effectively in a wide pH range (pH 3-9), and it has strong adaptability to environmental conditions. Fenton oxidation method: It has strict requirements on pH value, usually needs to be operated under acidic conditions (pH 2.5-3.5), and the reaction temperature and time need to be strictly controlled, and the operating conditions are relatively harsh. 4) Reaction time: Persulfate oxidation method: The reaction time is short, it is less affected by temperature, and it can complete the degradation of organic matter in a short time, with high treatment efficiency. Fenton oxidation method: The reaction time is long, especially under low temperature conditions, it takes longer to achieve the ideal treatment effect, and the treatment efficiency is relatively low. 5) Secondary pollution: Persulfate oxidation method: Sulfate ions are mainly produced as by-products during the reaction, which has little impact on the environment, and no additional catalyst is required, reducing the risk of secondary pollution. Fenton oxidation method: A large amount of ferrous ions are required as catalysts, and a large amount of iron sludge is produced after the reaction, which requires secondary treatment, increasing the treatment cost and complexity. 6) Cost and operation: Persulfate oxidation method: Although the preparation cost of persulfate is high, its reaction efficiency is high, no additional catalyst is required, and the reaction conditions are mild, and the overall operating cost is relatively low. Fenton oxidation method: Although the reagent cost is low, a large amount of iron ions are required as catalysts, and the reaction conditions are harsh, requiring additional acid-base adjustment and iron sludge treatment, and the overall cost is high. 7) Scope of application: Persulfate oxidation method: It is applicable to various types of wastewater, especially high-concentration, difficult-to-degrade organic wastewater (such as coking wastewater, landfill leachate, etc.), and can maintain efficient treatment under low temperature conditions. Fenton oxidation method: It is more suitable for treating medium-concentration organic wastewater, has high requirements for reaction conditions, and is not effective under low temperature conditions. 8) Stability and storage: Persulfate oxidation method: Persulfate has stable chemical properties, is easy to store and transport, and is easy to manage, which reduces the risks during storage and transportation. Fenton oxidation method: Hydrogen peroxide is easy to decompose during storage and transportation, and requires strict control of conditions, which increases the difficulty of storage and transportation. 9) Potential for combined application: Persulfate oxidation method: It can be used in combination with other treatment technologies (such as biological treatment, photocatalysis, etc.) to further improve the treatment effect, and the combined application is highly flexible. Fenton oxidation method: Although it can also be used in combination with other technologies, the harshness of its reaction conditions limits the flexibility and extensiveness of combined applications.

[0024] 3. The anaerobic section adopts a folded plate anaerobic biological iron fluidized bed: 1) Superior hydraulic conditions: plug flow state, ABR uses carefully designed baffles to make the water flow form a plug flow state in the reactor, effectively prolonging the contact time between wastewater and microorganisms and improving mass transfer efficiency. 2) Turbulence enhanced mass transfer: The improved ABR (such as mABR) adopts a special wave folded plate design to induce turbulence in the water flow, further enhancing the mass transfer efficiency, and is particularly suitable for the treatment of low-concentration wastewater. 3) High volume utilization: The design of the baffle greatly improves the volume utilization of the reactor, effectively reduces the volume and floor space of the reactor, and makes space utilization more efficient. 4) Simple structure, stable and reliable operation: No complex three-phase separator, compared with UASB (Upflow Anaerobic Sludge Blanket) technology, ABR eliminates the complex three-phase separator, has a simpler structure, and significantly reduces the operation and maintenance costs. 5) Strong anti-blocking ability: The design of the baffle effectively reduces the risk of sludge swelling and blockage, ensuring that the reactor can operate stably for a long time. 6) High operational flexibility: The baffle spacing or reaction chamber volume ratio can be flexibly adjusted according to changes in water quality and water volume, and even intermittent operation is supported to meet various treatment needs. 7) Reasonable and efficient microbial distribution: The microbial community along the process is optimized, and each reaction chamber can cultivate an adaptive microbial community according to the influent substrate concentration and environmental conditions. The front-end reaction chamber is mainly composed of hydrolysis and acid-producing bacteria, while the back-end reaction chamber is mainly composed of methanogens. This distribution method significantly improves the overall treatment efficiency. 8) Significant phase separation effect: ABR achieves effective separation of acid-producing phase and methanogenic phase in anaerobic reaction, reduces the accumulation of intermediate products, and thus increases the reaction rate. 9) Excellent solid-liquid separation effect and effluent water quality: Good solid-liquid separation, baffles and sludge settling work together to effectively intercept biological solids and ensure excellent effluent water quality. Low suspended solids concentration: The improved ABR further reduces the suspended solids concentration in the effluent by optimizing the reaction chamber design, thereby improving the water quality standard. 10) Strong anti-shock load capability: The water quality and water quantity have strong adaptability. ABR shows good adaptability to both hydraulic shock load and organic shock load, and can maintain stable operation even under high-concentration wastewater shock. 11) Toxic substance resistance: The improved ABR optimizes the distribution of microbial communities, enhances the system's tolerance to toxic substances, and improves the stability and reliability of treatment. 12) Energy recovery and economy: Efficient collection of biogas. ABR can collect biogas produced by each reaction chamber separately, avoid mixing of gases at different stages, and improve energy recovery efficiency. 13) Low operating cost: Due to its simple structure, stable operation and no need for complex equipment, ABR significantly reduces construction and operation costs and is extremely economical.

[0025] In summary, the method for treating high-concentration wastewater provided by the present invention has at least the following characteristics: 1. Low operating cost. Compared with other combined processes, the operating cost of this process is about 5-8 yuan / cubic meter of water, while other processes are generally more than 10 yuan / cubic meter of water; 2. Low operation and maintenance difficulty; 3. High treatment efficiency, total nitrogen removal rate> 90%, COD removal rate> 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0028] Figure 1 The present invention is a flowchart of a method for treating high-concentration wastewater.

[0029] Figure 2 This is a schematic diagram of the structure of an anaerobic ammonium oxidation reactor in the method for treating high-concentration wastewater provided by the present invention.

[0030] Figure 3 It is a schematic diagram of the structure of the ABR anaerobic folded plate reactor disclosed in the prior art.

[0031] Figure 4 This is a schematic structural diagram of the improved folded plate anaerobic reactor in the method for treating high-concentration wastewater provided by the present invention.

[0032] Figure 5 This is a schematic structural diagram of a persulfate oxidation reactor in the method for treating high-concentration wastewater provided by the present invention.

[0033] Figure 6 The present invention provides a flowchart of a method for treating high-concentration wastewater in Example 1. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0036] The core technical concept of the high-concentration wastewater treatment method provided by the present invention is as follows: The present invention mainly adopts "coagulation sedimentation + persulfate advanced oxidation" and then enters the "anaerobic + aerobic + anaerobic ammonia oxidation denitrification" combined process to ensure that the effluent water quality of high-concentration wastewater is stable and meets the standards.

[0037] 1. Preprocessing stage Coagulation and sedimentation method: by adding coagulants to the wastewater, the stability of the wastewater is reduced, and pollutants such as suspended solids, colloids and insoluble organic matter can be removed. This method provides more stable water inlet conditions for subsequent treatment processes and ensures treatment efficiency.

[0038] Persulfate advanced oxidation technology: This technology uses low-valent transition metal ions (such as Fe 2+ ) activates persulfate to produce a large number of sulfate radicals. These free radicals undergo a series of redox chemical reactions with the refractory organic matter in the water, effectively decomposing and mineralizing these organic pollutants. The redox potential of sulfate radicals (2.5-3.1V) is higher than that of hydroxyl radicals (·OH) (1.9-2.7V), and their stability and half-life are longer. By effectively controlling the generation rate of sulfate radicals, their quenching time can be extended to 3-5s, thereby promoting the degradation of refractory organic matter in industrial wastewater in a targeted manner, especially when treating aromatic pollutants.

[0039] 2. Biochemical treatment stage Folded plate anaerobic fluidized bed: The folded plate anaerobic reactor (ABR) was developed by American McCarty in 1982. It has a vertical guide plate inside to divide the reactor into several reaction chambers in series. Each reaction chamber is equivalent to an independent upflow sludge bed (UASB) system. By using it in series, it is closer to plug flow reaction, which is conducive to domesticating and cultivating microbial communities adapted to the local environmental conditions. Domesticating acid-producing bacteria in zone I and methanogenic bacteria in zone II greatly improves the treatment efficiency. The folded plate composite anaerobic biological fluidized bed used in this scheme is improved on the basis of ordinary ABR. It absorbs the advantages of anaerobic fluidized bed. A carrier with small filling particle size and large specific surface area is added to the rear end of the reactor, so that anaerobic microorganisms form a biofilm on the surface of the carrier. The carrier is in a fluidized state with good mass transfer conditions. The microorganisms are easy to fully contact with the wastewater, the bacteria are highly active, and the equipment treatment efficiency is 30% higher than that of the general anaerobic process.

[0040] Aerobic fluidized bed: Aerobic fluidized bed uses sand, activated carbon, coke and other smaller inert particles as carriers to fill the bed, and the surface of the carrier is covered with biofilm. The sewage flows from bottom to top at a certain flow rate, so that the carrier particles are in a fluidized state, thereby increasing the contact area between the biofilm and the wastewater and fully supplying oxygen. The boiling state of the filler is used to strengthen the biological treatment process of wastewater. The surface area of ​​the filler in the structure exceeds 3300m² / m³, and the biofilm rarely falls off, which can save the secondary sedimentation tank. The suspended solid concentration of the mixed liquid in the bed reaches 8000-40000mg / L, and the oxygen utilization rate exceeds 90%. The aerobic fluidized bed process has high efficiency, small footprint, and low investment. It has been widely used in deep treatment such as sewage nitrification and denitrification, secondary sewage treatment, and treatment of industrial wastewater containing phenols and pharmaceuticals.

[0041] Anaerobic ammonium oxidation (ANAMMOX) process: The anaerobic ammonium oxidation process was first studied by Delft University of Technology in the Netherlands in the late 20th century and was successfully developed and applied in the early 21st century. The process is based on the ANAMMOX reaction discovered in the 1990s. It uses ammonia as an electron donor and nitrite as an electron acceptor to generate nitrogen gas under anaerobic conditions. This reaction has made great breakthroughs in the concept and technology of traditional biological denitrification processes, and has the advantages of high denitrification efficiency, low operating costs, and small footprint. At present, the process has become increasingly mature in the field of municipal sludge treatment. For example, the world's first production-scale ANAMMOX device at the Dokhaven sewage treatment plant in Rotterdam, the Netherlands, has a volumetric nitrogen removal rate (NRR) of up to 9.5kgN / (m 3 ·d). In addition, the promotion of ANAMMOX process in the treatment of high-ammonia nitrogen wastewater such as fermentation industrial wastewater, landfill leachate, and aquaculture wastewater has also been gradually carried out, and its engineering application is showing a booming trend.

[0042] The technical solution provided by the present invention is as follows: The present invention provides a method for treating high-concentration wastewater, which comprises the following steps: The high-concentration wastewater to be treated is subjected to coagulation and sedimentation, and then subjected to oxidation treatment to obtain the first wastewater; The first wastewater is sequentially subjected to a first hydrolysis reaction treatment, a first anaerobic reaction treatment and a first aerobic reaction treatment to obtain a second wastewater; The second wastewater is sequentially subjected to a second hydrolysis reaction treatment, a second anaerobic reaction treatment, and a second aerobic reaction treatment to obtain a third wastewater; The third wastewater is subjected to a denitrification reaction treatment, and then subjected to a mud-water separation treatment to obtain treated discharge water; The physical and chemical property parameters of the high-concentration wastewater to be treated include: chemical oxygen demand>20000mg / L, total nitrogen content>3000mg / L and salt content>5000mg / L; The oxidation treatment method is a persulfate advanced oxidation method; The first anaerobic reaction treatment and the second anaerobic reaction treatment are both carried out by using a folded plate anaerobic biological iron fluidized bed, wherein the folded plate anaerobic biological iron fluidized bed is a biological fluidized bed component added to the rear end of an anaerobic baffled reactor; The denitrification reaction treatment method is anaerobic ammonium oxidation.

[0043] The present invention provides a method for treating high-concentration wastewater. The present invention mainly adopts "coagulation sedimentation + persulfate advanced oxidation" and then enters the "anaerobic + aerobic + anaerobic ammonia oxidation denitrification" combined process to ensure that the effluent water quality of high-concentration wastewater is stable and meets the standards, effectively solving the problems of high operating cost and poor sewage treatment effect existing in the prior art.

[0044] The improved ABR anaerobic folded plate reactor of the present invention is as follows Figure 3 The end of the existing ABR anaerobic folded plate reactor shown in the figure is added with a biological fluidized bed (the biological fluidized bed is filled with smaller inert particles such as sand, activated carbon, coke, etc. as carriers in the bed, the surface of the carrier is covered with a biofilm, and the sewage flows from bottom to top at a certain flow rate, so that the carrier particles are in a fluidized state. The wastewater flows from bottom to top through the sand bed to make the carrier layer in a flowing state, thereby increasing the contact area between the biofilm and the wastewater per unit time and fully supplying oxygen, and utilizing the boiling state of the filler to strengthen the structure of the wastewater biological treatment process), and the following is obtained. Figure 4 The improved folded plate anaerobic reactor shown.

[0045] In some specific embodiments, the step of subjecting the high-concentration wastewater to be treated to coagulation and sedimentation, and then subjecting it to oxidation treatment to obtain the first wastewater comprises the following process: Passing the high-concentration wastewater to be treated into a regulating tank, and then passing it into a coagulation tank containing a coagulant, a flocculation tank containing a flocculant, and a persulfate oxidation tank containing persulfate in sequence for treatment to obtain the first wastewater; The operating conditions of the coagulation tank include: pH 8-12; temperature 25-27°C; time 0.5h; in terms of weight percentage, the added weight of the coagulant is 0.02% of the weight of the high-concentration wastewater to be treated, and the coagulant includes iron salt; the iron salt includes ferric chloride, ferrous sulfate, ferric sulfate, polyferric sulfate, etc. The operating condition parameters of the flocculation tank include: pH 8-12; temperature 25-27°C; time 0.5h; in terms of weight percentage, the added weight of the flocculant is 0.006% of the weight of the high-concentration wastewater to be treated, and the flocculant includes polyacrylamide; The operating condition parameters of the persulfate oxidation tank include: pH 2-12; temperature 25-27°C; time 0.5h; in terms of weight percentage, the added weight of the persulfate is 0.16% of the weight of the high-concentration wastewater to be treated.

[0046] In some specific embodiments, the structural schematic diagram of the persulfate oxidation reactor is as follows Figure 5 shown.

[0047] In some specific embodiments, the step of subjecting the first wastewater to a first hydrolysis reaction treatment, a first anaerobic reaction treatment, and a first aerobic reaction treatment in sequence to obtain the second wastewater comprises the following process: Passing the first wastewater into a primary hydrolysis fluidized bed, a primary folded plate anaerobic biological iron fluidized bed and a primary aerobic fluidized bed in sequence for treatment to obtain the second wastewater; The operating conditions of the primary hydrolysis fluidized bed include: dissolved oxygen <1 mg / L, pH 4-7, temperature 20-35°C, and time 40h; The operating condition parameters of the first-stage folded plate anaerobic biological iron fluidized bed include: dissolved oxygen <0.5 mg / L, pH 6-8, temperature 20-35°C, and time 46 hours; The operating condition parameters of the primary aerobic fluidized bed include: dissolved oxygen of 2-6 mg / L, pH of 6-8, temperature of 20-35° C., and time of 38 hours.

[0048] In some specific embodiments, the step of subjecting the second wastewater to a second hydrolysis reaction treatment, a second anaerobic reaction treatment, and a second aerobic reaction treatment in sequence to obtain the third wastewater comprises the following process: The second wastewater is passed into the intermediate water tank 1, and then passed into the secondary hydrolysis fluidized bed, the secondary folded plate anaerobic biological iron fluidized bed and the secondary aerobic fluidized bed in sequence for treatment to obtain the third wastewater; The operating condition parameters of the secondary hydrolysis fluidized bed and the primary hydrolysis fluidized bed are the same; The operating condition parameters of the secondary folded plate anaerobic biological iron fluidized bed and the primary folded plate anaerobic biological iron fluidized bed are the same; The operating condition parameters of the secondary aerobic fluidized bed and the primary aerobic fluidized bed are the same.

[0049] In some specific embodiments, the step of subjecting the third wastewater to denitrification reaction treatment and then subjecting it to mud-water separation treatment to obtain treated discharge water comprises the following process: The third wastewater is passed into the intermediate water tank 2, and then sequentially passed into the anaerobic ammonia oxidation tank for denitrification reaction and the final sedimentation tank for mud-water separation to obtain the discharge water; The operating conditions of the anaerobic ammonium oxidation tank include: dissolved oxygen <0.5 mg / L, pH 6-8, temperature 26-35°C, and time 8 hours; The operating conditions of the final sedimentation tank include: temperature of 25-27°C and time of 4 hours.

[0050] In some specific embodiments, the anaerobic ammonium oxidation in the present invention can be carried out as follows Figure 2 The anaerobic ammonia oxidation reactor shown in the figure is carried out; wherein, the pH meter is used to measure the pH in the reactor and control it at 6.8~7.2. If the pH is lower than 6.8, alkali is added, and if it is higher than 7.2, acid is added for adjustment; the water bath thermostat is used to heat the reactor and control the temperature inside the reactor to 30~40 degrees; the function of the agitator is to mix the wastewater in the reactor evenly and promote the reaction process; the buffer tank is the wastewater inlet, the drain outlet is the wastewater outlet, and the gas generated by the reaction is discharged from the water seal bottle.

[0051] In some specific embodiments, the method for treating high-concentration wastewater further comprises: The sludge from the flocculation tank, the first-stage folded plate anaerobic biological iron fluidized bed, the second-stage folded plate anaerobic biological iron fluidized bed and the final sedimentation tank is collected in a sludge thickening tank and then subjected to filter pressing treatment through a sludge filter press.

[0052] In some specific embodiments, the sludge from the primary aerobic fluidized bed and the secondary aerobic fluidized bed is returned to the primary hydrolysis fluidized bed and the secondary hydrolysis fluidized bed.

[0053] In some specific embodiments, the supernatant of the sludge thickening tank and the filtrate of the sludge filter press are both returned to the regulating tank.

[0054] In some specific embodiments, the physical and chemical property parameters of the treated wastewater include: chemical oxygen demand <10000 mg / L, total nitrogen content <600 mg / L and salt content <4800 mg / L.

[0055] It should be noted that the raw materials involved in the method for treating high-concentration wastewater provided by the present invention, unless otherwise specified or specifically described, can be directly commercially available products or homemade according to the preparation process disclosed in the prior art; at the same time, the operating steps and condition parameters involved, unless otherwise specified or specifically described, can be carried out according to the existing wastewater treatment process steps and parameter conditions or using existing equipment, and the present invention document will not repeat them one by one.

[0056] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0057] Example 1 This example provides a method for treating high-concentration wastewater. Figure 6 As shown, the following steps are included: The wastewater to be treated is first collected through the sewage pipe and then enters the regulating tank. The function of the regulating tank is to fully mix the wastewater to achieve a uniform quality and quantity effect; Next, the wastewater in the regulating tank is pumped to the coagulation tank and flocculation tank through a lifting pump. In these two tanks, the pH value of the wastewater is controlled between 8 and 12 by adding acid or alkali; at the same time, coagulants (iron salt-ferric chloride) and flocculants (PAM) are added to the coagulation tank and flocculation tank, and fully stirred to make the suspended matter in the wastewater coagulate and precipitate. After that, the wastewater enters the persulfate oxidation tank; In the persulfate oxidation tank, persulfate is added to break the chains of large molecular complex organic matter in the wastewater and convert it into small molecular compounds, thus facilitating subsequent biochemical treatment; Subsequently, the wastewater enters the primary hydrolysis fluidized bed for hydrolysis reaction. During this process, the dissolved oxygen is controlled to be less than 1 mg / L and the pH value is between 4 and 6; Next, the wastewater enters the primary folded plate anaerobic biological iron fluidized bed for anaerobic reaction. At this stage, the dissolved oxygen needs to be controlled below 0.5 mg / L and the pH value needs to be between 6 and 8. Then, the wastewater enters the primary aerobic fluidized bed for aerobic reaction. During this process, the dissolved oxygen is controlled between 2 and 6 mg / L, and the pH value is also maintained between 68; Next, the wastewater enters the intermediate water tank 1 for uniform mixing. Afterwards, it is treated in the secondary hydrolysis fluidized bed, the secondary folded plate anaerobic biological iron fluidized bed and the secondary aerobic fluidized bed in sequence, and finally enters the intermediate water tank 2; the control parameters of these stages are the same as those of the primary treatment stage; The wastewater then enters the anaerobic ammonium oxidation tank for denitrification. During this process, the dissolved oxygen needs to be controlled below 0.5 mg / L and the pH value needs to be between 7 and 8. Finally, the wastewater enters the final sedimentation tank for mud and water separation. The separated sludge is filtered through a filter press and then transported for disposal, while the wastewater is finally discharged into the integrated sewage treatment plant in the factory for further treatment; The sludge produced by the flocculation tank, the first-stage folded plate anaerobic biological iron fluidized bed, the second-stage folded plate anaerobic biological iron fluidized bed and the final sedimentation tank is collected in the sludge thickening tank and then filtered through the sludge filter press. The sludge produced by the primary aerobic fluidized bed and the secondary aerobic fluidized bed is returned to the primary hydrolysis fluidized bed and the secondary hydrolysis fluidized bed to realize the recycling of the sludge; The supernatant from the sludge thickening tank and the filtrate from the sludge filter press are returned to the regulating tank for subsequent treatment processes.

[0058] In this example, the pollutant removal efficiency of each unit is shown in Table 1, and the specific operating parameters of each unit are shown in Table 2.

[0059] Table 1 Pollutant removal efficiency of each unit

[0060] Table 2 Specific operating parameters of each unit

[0061] Comparative Example 1 This example provides a method for treating high-concentration wastewater. The only difference from Example 1 is that the oxidation treatment method in Example 1 is adjusted from the persulfate advanced oxidation method to the Fenton oxidation method. Figure 4 The modified folded plate anaerobic reactor shown is adjusted as follows Figure 3 The existing ABR anaerobic folded plate reactor shown in the figure adjusts the denitrification reaction treatment method from anaerobic ammonium oxidation to AO denitrification process; The working conditions of the Fenton oxidation method include: pH 2-4, reaction temperature 20-40 o C, Fe 2+ The molar ratio of H2O2 dosage is 1:6, and the reaction time is 60 minutes; The working condition parameters of the AO denitrification process include: sludge age 10-30 days, hydraulic retention time (anaerobic 1.5h, aerobic 8h), reflow ratio (sludge reflow ratio 80%; mixed liquor reflow ratio 200%).

[0062] Comparative Example 2 This example provides a method for treating high-concentration wastewater, which differs from Example 1 only in that the oxidation treatment method in Example 1 is adjusted from the persulfate advanced oxidation method to the Fenton oxidation method, and the working condition parameters of the Fenton oxidation method are the same as those of Comparative Example 1.

[0063] Comparative Example 3 This example provides a method for treating high-concentration wastewater, which differs from Example 1 only in that: Figure 4 The modified folded plate anaerobic reactor shown is adjusted as follows Figure 3 The existing ABR anaerobic folded plate reactor is shown.

[0064] Comparative Example 4 This example provides a method for treating high-concentration wastewater, which differs from Example 1 only in that the denitrification reaction treatment method is adjusted from the anaerobic ammonium oxidation method to the AO denitrification process, and the AO denitrification process is the same as that of Comparative Example 1.

[0065] For high-concentration wastewater to be treated with the same composition and meeting the same effluent standard, the operating costs of Example 1 and Comparative Examples 1 to 4 are shown in Table 3, calculated based on 10 tons of wastewater to be treated.

[0066] Table 3 Operation cost table of Example 1 and Comparative Examples 1 to 4

[0067] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0068] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for treating high-concentration wastewater, characterized in that: The method for treating high-concentration wastewater comprises the following steps: The high-concentration wastewater to be treated is subjected to coagulation and sedimentation, and then subjected to oxidation treatment to obtain the first wastewater; The first wastewater is sequentially subjected to a first hydrolysis reaction treatment, a first anaerobic reaction treatment and a first aerobic reaction treatment to obtain a second wastewater; The second wastewater is sequentially subjected to a second hydrolysis reaction treatment, a second anaerobic reaction treatment, and a second aerobic reaction treatment to obtain a third wastewater; The third wastewater is subjected to a denitrification reaction treatment, and then subjected to a mud-water separation treatment to obtain treated discharge water; The physical and chemical property parameters of the high-concentration wastewater to be treated include: chemical oxygen demand>20000mg / L, total nitrogen content>3000mg / L and salt content>5000mg / L; The oxidation treatment method is a persulfate advanced oxidation method; The first anaerobic reaction treatment and the second anaerobic reaction treatment are both carried out by using a folded plate anaerobic biological iron fluidized bed, wherein the folded plate anaerobic biological iron fluidized bed is a biological fluidized bed component added to the rear end of an anaerobic baffled reactor; The denitrification reaction treatment method is anaerobic ammonium oxidation.

2. The method for treating high-concentration wastewater according to claim 1, characterized in that: The step of coagulating and settling the high-concentration wastewater to be treated and then oxidizing it to obtain the first wastewater comprises the following process: Passing the high-concentration wastewater to be treated into a regulating tank, and then passing it into a coagulation tank containing a coagulant, a flocculation tank containing a flocculant, and a persulfate oxidation tank containing persulfate in sequence for treatment to obtain the first wastewater; The operating conditions of the coagulation tank include: pH 8-12; temperature 25-27°C; time 0.5h; in terms of weight percentage, the added weight of the coagulant is 0.02% of the weight of the high-concentration wastewater to be treated, and the coagulant includes iron salt; The operating condition parameters of the flocculation tank include: pH 8-12; temperature 25-27°C; time 0.5h; in terms of weight percentage, the added weight of the flocculant is 0.0006% of the weight of the high-concentration wastewater to be treated, and the flocculant includes polyacrylamide; The operating condition parameters of the persulfate oxidation tank include: pH 2-12; temperature 25-27°C; time 4h; in terms of weight percentage, the added weight of the persulfate is 0.16% of the weight of the high-concentration wastewater to be treated.

3. The method for treating high-concentration wastewater according to claim 2, characterized in that: The step of sequentially subjecting the first wastewater to a first hydrolysis reaction treatment, a first anaerobic reaction treatment, and a first aerobic reaction treatment to obtain a second wastewater comprises the following process: Passing the first wastewater into a primary hydrolysis fluidized bed, a primary folded plate anaerobic biological iron fluidized bed and a primary aerobic fluidized bed in sequence for treatment to obtain the second wastewater; The operating conditions of the primary hydrolysis fluidized bed include: dissolved oxygen <1 mg / L, pH 4-7, temperature 20-35°C, and time 40h; The operating condition parameters of the first-stage folded plate anaerobic biological iron fluidized bed include: dissolved oxygen <0.5 mg / L, pH 6-8, temperature 20-35°C, and time 46 hours; The operating condition parameters of the primary aerobic fluidized bed include: dissolved oxygen of 2-6 mg / L, pH of 6-8, temperature of 20-35° C., and time of 38 hours.

4. The method for treating high-concentration wastewater according to claim 3, characterized in that: The step of sequentially subjecting the second wastewater to a second hydrolysis reaction treatment, a second anaerobic reaction treatment, and a second aerobic reaction treatment to obtain the third wastewater comprises the following process: The second wastewater is passed into the intermediate water tank 1, and then passed into the secondary hydrolysis fluidized bed, the secondary folded plate anaerobic biological iron fluidized bed and the secondary aerobic fluidized bed in sequence for treatment to obtain the third wastewater; The operating condition parameters of the secondary hydrolysis fluidized bed and the primary hydrolysis fluidized bed are the same; The operating condition parameters of the secondary folded plate anaerobic biological iron fluidized bed and the primary folded plate anaerobic biological iron fluidized bed are the same; The operating condition parameters of the secondary aerobic fluidized bed and the primary aerobic fluidized bed are the same.

5. The method for treating high-concentration wastewater according to claim 4, characterized in that: The step of subjecting the third wastewater to denitrification reaction treatment and then subjecting it to mud-water separation treatment to obtain treated discharge water comprises the following process: The third wastewater is passed into the intermediate water tank 2, and then sequentially passed into the anaerobic ammonia oxidation tank for denitrification reaction and the final sedimentation tank for mud-water separation to obtain the discharge water; The operating conditions of the anaerobic ammonium oxidation tank include: dissolved oxygen <0.5 mg / L, pH 6-8, temperature 26-35°C, and time 8 hours; The operating conditions of the final sedimentation tank include: temperature of 25-27°C and time of 4 hours.

6. The method for treating high-concentration wastewater according to claim 5, characterized in that: The method for treating high-concentration wastewater also includes: The sludge from the flocculation tank, the first-stage folded plate anaerobic biological iron fluidized bed, the second-stage folded plate anaerobic biological iron fluidized bed and the final sedimentation tank is collected in a sludge thickening tank and then subjected to filter pressing treatment through a sludge filter press.

7. The method for treating high-concentration wastewater according to claim 6, characterized in that: The sludge in the primary aerobic fluidized bed and the secondary aerobic fluidized bed is returned to the primary hydrolysis fluidized bed and the secondary hydrolysis fluidized bed respectively.

8. The method for treating high-concentration wastewater according to claim 7, characterized in that: The supernatant of the sludge thickening tank and the filtrate of the sludge filter press are both returned to the regulating tank.

9. The method for treating high-concentration wastewater according to any one of claims 1 to 8, characterized in that: The physical and chemical property parameters of the treated discharge water include: chemical oxygen demand <10000 mg / L, total nitrogen content <600 mg / L and salt content <4800 mg / L.

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