A method for treating high-concentration wastewater

Abstract

The present invention relates to a method for treating high-concentration wastewater, belonging to the technical field of wastewater treatment. The method for treating high-concentration wastewater comprises the following steps: subjecting the high-concentration wastewater to be treated to coagulation precipitation, and then performing oxidation treatment to obtain first wastewater; sequentially subjecting the first wastewater to a first hydrolysis reaction treatment, a first anaerobic reaction treatment and a first aerobic reaction treatment to obtain second wastewater; sequentially subjecting the second wastewater to a second hydrolysis reaction treatment, a second anaerobic reaction treatment and a second aerobic reaction treatment to obtain third wastewater; subjecting the third wastewater to a denitrification reaction treatment, and then performing sludge-water separation treatment and other steps. The present invention mainly adopts "coagulation precipitation + persulfate advanced oxidation", and then enters the "anaerobic + aerobic + anaerobic ammonium oxidation denitrification" combined process to ensure that the effluent quality of high-concentration wastewater meets the standards stably, and effectively solves the problems of high operation cost and poor sewage treatment effect existing in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly 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 day by day. Among them, high-concentration wastewater is extremely difficult to treat due to its characteristics such as high chemical oxygen demand (COD > 20000 mg / L), high total nitrogen (> 3000 mg / L), and high salt content (> 5000 mg / L), posing a serious threat to the environment. Such wastewater not only has a complex composition, but also has a high organic matter content, a high nitrogen content, and a large salt content. It is often difficult to meet the national discharge standards by simply adopting a traditional wastewater treatment process.

[0003] Currently, for the treatment of such high-concentration wastewater, there are mainly two common combined treatment processes:

[0004] 1. Anaerobic-aerobic-membrane treatment process:

[0005] This process usually uses an upflow anaerobic sludge bed (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, achieving the preliminary degradation of organic matter.

[0006] Subsequently, a membrane bioreactor (MBR) is used as the aerobic treatment unit to further oxidize and decompose the remaining organic matter by aerobic microorganisms and remove part of the nitrogen.

[0007] 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.

[0008] However, this process has the problem of high investment cost, especially in the membrane treatment unit. As a high-cost consumable material, the membrane generally needs to be replaced every 3 - 5 years, and its investment proportion in the whole process is relatively large. In addition, the operation and maintenance of the membrane are also relatively difficult and require professional technical and management personnel.

[0009] 2. Biological treatment + Fenton advanced oxidation + membrane treatment process:

[0010] This process combines the advantages of biological treatment, advanced oxidation, and membrane treatment. First, part of the organic matter and nitrogen in the wastewater are removed through the biological treatment unit.

[0011] Then, the Fenton advanced oxidation technology is adopted, and the strong oxidizing property of the Fenton reagent is used to further oxidize and decompose the refractory organic matter in the wastewater, improving the biodegradability of the wastewater.

[0012] Finally, deep purification is also carried out through membrane treatment technology to ensure that the effluent meets the standards.

[0013] However, this process also has the problem of high investment cost. Since a membrane treatment unit is adopted, the cost of membrane replacement is relatively high. At the same time, the operating cost of Fenton advanced oxidation is also relatively high, usually reaching 10 - 20 yuan per cubic meter of water, increasing the overall cost of wastewater treatment.

[0014] In summary, although the existing combined processes for treating high - concentration wastewater can effectively remove various pollutants in the wastewater to a certain extent, they generally have problems such as high investment cost, great difficulty in operation and maintenance, and high operating cost. Therefore, there is an urgent need to develop a method for treating high - concentration wastewater with low investment cost, simple operation and maintenance, low operating cost, and good treatment effect to meet the needs of actual production and the requirements of environmental protection. Summary of the Invention

[0015] To solve the above problems, the present invention provides a method for treating high - concentration wastewater.

[0016] The technical solution provided by the present invention is as follows:

[0017] The present invention provides a method for treating high - concentration wastewater, as Figure 1 shown, the method for treating high - concentration wastewater includes the following steps:

[0018] Carry out coagulation and sedimentation on the high - concentration wastewater to be treated, and then carry out oxidation treatment to obtain the first wastewater;

[0019] Carry out the first hydrolysis reaction treatment, the first anaerobic reaction treatment and the first aerobic reaction treatment on the first wastewater in sequence to obtain the second wastewater;

[0020] Carry out the second hydrolysis reaction treatment, the second anaerobic reaction treatment and the second aerobic reaction treatment on the second wastewater in sequence to obtain the third wastewater;

[0021] Carry out denitrification reaction treatment on the third wastewater, and then carry out sludge - water separation treatment to obtain the treated effluent;

[0022] Among them, the physical and chemical property parameters of the high - concentration wastewater to be treated include: chemical oxygen demand > 20000 mg / L, total nitrogen content > 3000 mg / L, and salt content > 5000 mg / L;

[0023] The oxidation treatment method is persulfate advanced oxidation method;

[0024] Both the first anaerobic reaction treatment and the second anaerobic reaction treatment are carried out using a corrugated - plate anaerobic biological iron fluidized bed, and the corrugated - plate anaerobic biological iron fluidized bed is a biological fluidized bed component added to the rear end of an anaerobic baffled reactor;

[0025] The denitrification reaction treatment method is anaerobic ammonium oxidation method.

[0026] Furthermore, the steps of subjecting the high-concentration wastewater to be treated to coagulation precipitation and then oxidation treatment to obtain the first wastewater include the following processes:

[0027] Introduce the high-concentration wastewater to be treated into an adjustment tank, and then sequentially introduce it into a coagulation tank containing a coagulant, a flocculation tank containing a flocculant, and a persulfate oxidation tank containing persulfate for treatment to obtain the first wastewater;

[0028] The operating condition parameters of the coagulation tank include: pH is 8 - 12; temperature is 25 - 27 °C; time is 0.5 h; by weight percentage, the addition weight of the coagulant is 0.02% of the weight of the high-concentration wastewater to be treated, and the coagulant includes iron salts;

[0029] The operating condition parameters of the flocculation tank include: pH is 8 - 12; temperature is 25 - 27 °C; time is 0.5 h; by weight percentage, the addition weight of the flocculant is 0.006% of the weight of the high-concentration wastewater to be treated, and the flocculant includes polyacrylamide;

[0030] The operating condition parameters of the persulfate oxidation tank include: pH is 2 - 12; temperature is 25 - 27 °C; time is 4 h; by weight percentage, the addition weight of the persulfate is 0.16% of the weight of the high-concentration wastewater to be treated.

[0031] Furthermore, the steps 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 include the following processes:

[0032] Introduce the first wastewater into a first-stage hydrolysis fluidized bed, a first-stage folded-plate anaerobic biological iron fluidized bed, and a first-stage aerobic fluidized bed in sequence for treatment to obtain the second wastewater;

[0033] Among them, the operating condition parameters of the first-stage hydrolysis fluidized bed include: dissolved oxygen < 1 mg / L, pH is 4 - 7, temperature is 20 - 35 °C, time is 40 h;

[0034] The operating condition parameters of the first-stage folded-plate anaerobic biological iron fluidized bed include: dissolved oxygen < 0.5 mg / L, pH is 6 - 8, temperature is 20 - 35 °C, time is 46 h;

[0035] The operating condition parameters of the first-stage aerobic fluidized bed include: dissolved oxygen is 2 - 6 mg / L, pH is 6 - 8, temperature is 20 - 35 °C, time is 38 h.

[0036] Further, the step of subjecting the second wastewater to a second hydrolysis reaction treatment, a second anaerobic reaction treatment, and a second aerobic reaction treatment to obtain a third wastewater includes the following process:

[0037] The second wastewater is introduced into an intermediate water tank 1 and then successively introduced into a secondary hydrolysis fluidized bed, a secondary folded-plate anaerobic biological iron fluidized bed, and a secondary aerobic fluidized bed for treatment to obtain the third wastewater;

[0038] The operating conditions and parameters of the secondary hydrolysis fluidized bed are the same as those of the primary hydrolysis fluidized bed;

[0039] The operating conditions and parameters of the secondary folded-plate anaerobic biological iron fluidized bed are the same as those of the primary folded-plate anaerobic biological iron fluidized bed;

[0040] The operating conditions and parameters of the secondary aerobic fluidized bed are the same as those of the primary aerobic fluidized bed.

[0041] Further, the step of subjecting the third wastewater to a denitrification reaction treatment and then to a sludge-water separation treatment to obtain treated effluent includes the following process:

[0042] The third wastewater is introduced into an intermediate water tank 2 and then successively introduced into an anaerobic ammonium oxidation tank for denitrification reaction and a final sedimentation tank for sludge-water separation to obtain the effluent;

[0043] The operating conditions and parameters of the anaerobic ammonium oxidation tank include: dissolved oxygen < 0.5 mg / L, pH of 6 - 8, temperature of 26 - 35 °C, and time of 8 h;

[0044] The operating conditions and parameters of the final sedimentation tank include: temperature of 25 - 27 °C and time of 4 h.

[0045] Further, the treatment method for the high-concentration wastewater further includes:

[0046] The sludge from the flocculation tank, the primary folded-plate anaerobic biological iron fluidized bed, the secondary folded-plate anaerobic biological iron fluidized bed, and the final sedimentation tank is collected in a sludge thickening tank and then subjected to pressure filtration treatment together through a sludge filter press.

[0047] Further, the sludge of the primary aerobic fluidized bed and the secondary aerobic fluidized bed is recycled to the primary hydrolysis fluidized bed and the secondary hydrolysis fluidized bed.

[0048] Further, the supernatant of the sludge thickening tank and the filtrate of the sludge filter press are both recycled to the adjustment tank.

[0049] Further, the physical and chemical property parameters of the treated effluent include: chemical oxygen demand < 10000 mg / L, total nitrogen content < 600 mg / L, and salt content < 4800 mg / L.

[0050] The above technical solutions provided by the embodiments of the present invention have at least the following advantages compared with the prior art:

[0051] The present invention provides a method for treating high-concentration wastewater. The present invention mainly adopts "coagulation precipitation + persulfate advanced oxidation", and then enters the "anaerobic + aerobic + anaerobic ammonium oxidation denitrification" combined process to ensure that the effluent quality of high-concentration wastewater meets the standards stably, effectively solving the problems of high operating cost and poor sewage treatment effect existing in the prior art. Specifically:

[0052] 1. The denitrification reaction treatment method adopts the anaerobic ammonium oxidation method: 1) High denitrification ability: The anaerobic ammonium oxidation process can directly and efficiently convert ammonia nitrogen (NH4 + ), and nitrite nitrogen (NO2 - ), and nitrite nitrogen (NO2

[0053] efficiently into nitrogen gas (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 prominent, 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% - 60% of the traditional process, significantly reducing energy consumption. This process hardly relies on external carbon sources. Even when carbon sources need to be added, the dosage is reduced by 90% compared with the traditional process, effectively saving resources. The emissions of greenhouse gases (such as N2O) generated during the anaerobic ammonium oxidation process are less, 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 requirements, the operating cost of the anaerobic ammonium oxidation process is significantly lower than that of the traditional denitrification process, bringing significant economic benefits to wastewater treatment plants. In addition, the sludge production of this process is low, reducing the treatment and disposal costs of surplus sludge and further reducing the overall operating cost. 4) Small floor area: The anaerobic ammonium oxidation reactor has a compact volume and high treatment efficiency. Therefore, under the same treatment scale, its floor area is only 1 / 3 - 1 / 2 of the traditional process, effectively saving land resources. 5) Environmental friendliness: The main by-product generated during the anaerobic ammonium oxidation process is harmless nitrogen gas, which has no negative impact on the environment. This process can also reduce the alkalinity consumption by 45%, reducing the dependence on chemical agents, further reflecting its environmentally friendly characteristics.2. Compared with 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 radicals, although its redox potential is slightly lower than that of hydroxyl radicals (·OH, 2.6 V vs 2.8 V) in Fenton oxidation, the reaction lifetime of sulfate 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 radicals, its oxidation ability is very strong. However, its lifetime is short and the diffusion distance is limited, so the degradation efficiency of organic matter with complex structure is relatively low. 3) Reaction conditions: Persulfate oxidation method: The reaction conditions are relatively mild and can operate effectively within a wide pH range (pH 3 - 9), with strong adaptability to environmental conditions. Fenton oxidation method: It has strict requirements for pH value and usually needs to operate 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 shorter, less affected by temperature, and can complete the degradation of organic matter in a shorter time, with high treatment efficiency. Fenton oxidation method: The reaction time is longer, especially under low-temperature conditions, and it takes longer to achieve the ideal treatment effect, and the treatment efficiency is relatively low. 5) Secondary pollution: Persulfate oxidation method: During the reaction process, sulfate ions are mainly produced as by-products, which have 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 mud will be produced after the reaction, which needs secondary treatment, increasing the treatment cost and complexity. 6) Cost and operation: Persulfate oxidation method: Although the preparation cost of persulfate is relatively high, its reaction efficiency is high, no additional catalyst is required, and the reaction conditions are mild, so 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, and additional acid-base adjustment and iron mud treatment are required, so the comprehensive cost is relatively high. 7) Application scope: Persulfate oxidation method: It is applicable to various types of wastewater, especially high-concentration and difficult-to-degrade organic wastewater (such as coking wastewater, landfill leachate, etc.), and can maintain high treatment efficiency even under low-temperature conditions. Fenton oxidation method: It is more suitable for treating medium-concentration organic wastewater, has high requirements for reaction conditions, and has poor effects under low-temperature conditions. 8) Stability and storage: Persulfate oxidation method: Persulfate has stable chemical properties, is convenient for storage and transportation, and is easy to manage, reducing the risks during storage and transportation. Fenton oxidation method: Hydrogen peroxide is easily decomposed during storage and transportation, and strict conditions need to be controlled, increasing 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 has high flexibility. Fenton oxidation method: Although it can also be used in combination with other technologies, the harshness of its reaction conditions limits the flexibility and universality of combined application.

[0054] 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 are highly adaptable. 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 separately collect the biogas produced in each reaction chamber, 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 operating costs and is extremely economical.

[0055] In summary, the method for treating high-concentration wastewater provided by the present invention has at least the following characteristics:

[0056] 1. Low operating cost. Compared with other combined processes, the operating cost of this process is approximately 5 - 8 yuan per cubic meter of water, while that of other processes is generally > 10 yuan per cubic meter of water.

[0057] 2. Low operation and maintenance difficulty.

[0058] 3. High treatment efficiency. The total nitrogen removal rate > 90%, and the COD removal rate > 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The drawings herein are incorporated into and constitute a part of this specification, showing embodiments in accordance with the present invention and, together with the specification, are used to explain the principles of the present invention.

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0061] Figure 1 It is a flowchart of the method for treating high - concentration wastewater provided by the present invention.

[0062] Figure 2 It is a schematic structural diagram of an anaerobic ammonium oxidation reactor in the method for treating high - concentration wastewater provided by the present invention.

[0063] Figure 3 It is a schematic structural diagram of an ABR anaerobic baffled reactor disclosed in the prior art.

[0064] Figure 4 It is a schematic structural diagram of a modified baffled anaerobic reactor in the method for treating high - concentration wastewater provided by the present invention.

[0065] Figure 5 It is a schematic structural diagram of a persulfate oxidation reactor in the method for treating high - concentration wastewater provided by the present invention.

[0066] Figure 6 It is a flowchart of the method for treating high - concentration wastewater provided in Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0067] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0068] Unless otherwise specified, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchase or can be prepared by existing methods.

[0069] The core technical concept of the high-concentration wastewater treatment method provided by the present invention is as follows:

[0070] The present invention mainly adopts "coagulation precipitation + persulfate advanced oxidation", and then enters the combined process of "anaerobic + aerobic + anaerobic ammonium oxidation denitrification" to ensure the stable compliance of the effluent quality of high-concentration wastewater.

[0071] 1. Pretreatment stage

[0072] Coagulation precipitation method: By adding coagulants to the wastewater, the stability of the wastewater is reduced, and pollutants such as suspended solids, colloids, and insoluble organic matters are removed. This method provides more stable influent conditions for the subsequent treatment process and ensures the treatment efficiency.

[0073] Persulfate advanced oxidation technology: This technology uses low-valent transition metal element ions (such as Fe 2+ ) to activate persulfate to generate a large number of sulfate radicals. These radicals undergo a series of oxidation-reduction chemical reactions with the refractory organic matters in water, effectively decomposing and mineralizing these organic pollutants. The redox potential of sulfate radicals (2.5 - 3.1 V) is higher than that of hydroxyl radicals (·OH) (1.9 - 2.7 V), and their stability and half-life are longer. By effectively controlling the generation rate of sulfate radicals, the quenching time can be extended to 3 - 5 s, thereby directionally promoting the degradation of refractory organic matters in industrial wastewater, especially having advantages in treating aromatic pollutants.

[0074] 2. Biochemical treatment stage

[0075] Folded-plate anaerobic fluidized bed: The folded-plate anaerobic reactor (ABR) was developed by McCarty in the United States in 1982. Vertical baffle plates are installed inside it to divide the reactor into several serially connected reaction chambers. Each reaction chamber is equivalent to an independent upflow anaerobic sludge bed (UASB) system. By using it in series, it is closer to the plug-flow reaction, which is beneficial to domesticating and cultivating a microbial community adapted to the local environmental conditions. Acidogenic bacteria are domesticated and produced in Zone I, and methanogenic bacteria are domesticated and produced in Zone II. This way of zonal domestication greatly improves the treatment efficiency. The folded-plate composite anaerobic biological fluidized bed adopted in this scheme is improved on the basis of the ordinary ABR, absorbing the advantages of the anaerobic fluidized bed. Carriers with small particle size and large specific surface area are added at the rear end of the reactor, so that anaerobic microorganisms form biofilms on the surface of the carriers. The carriers are in a fluidized state, with good mass transfer conditions. Microorganisms are easy to come into full contact with the wastewater, the bacterial activity is high, and the treatment efficiency of the equipment is 30% higher than that of general anaerobic processes.

[0076] Aerobic fluidized bed: The aerobic fluidized bed is filled with smaller inert particles such as sand, activated carbon, and coke as carriers inside the bed, and the surface of the carriers is covered with biofilms. The sewage flows from bottom to top at a certain flow rate, making the carrier particles in a fluidized state, so as to increase the contact area between the biofilms and the wastewater and supply sufficient oxygen. The boiling state of the packing is used to strengthen the biological treatment process of the wastewater. The surface area of the packing in the structure exceeds 3300m 2 / m 3 , the biofilms rarely fall off, and the secondary sedimentation tank can be omitted. The concentration of mixed liquor suspended solids in the bed reaches 8000 - 40000mg / L, and the oxygen utilization rate exceeds 90%. The aerobic fluidized bed process has high efficiency, less land occupation, and low investment, and has been widely used in advanced treatment such as sewage nitrification and denitrification, secondary sewage treatment, and the treatment of industrial wastewater such as phenol-containing and pharmaceutical wastewater.

[0077] Anaerobic ammonium oxidation (ANAMMOX) process: The anaerobic ammonium oxidation process was initially studied by Delft University of Technology in the Netherlands at the end of the 20th century and was successfully developed and applied at the beginning of this century. This process is based on the ANAMMOX reaction discovered in the 1990s. Under anaerobic conditions, ammonia is used as the electron donor and nitrite is used as the electron acceptor to react to produce nitrogen gas. This reaction has greatly broken through the traditional biological nitrogen removal process in terms of concept and technology, and has the advantages of high nitrogen removal efficiency, low operating cost, and small land occupation space. At present, this process has become increasingly mature in the field of treating municipal sludge liquor. For example, the world's first full-scale ANAMMOX device in the Dokhaven Sewage Treatment Plant in Rotterdam, the Netherlands, has a volumetric nitrogen removal rate (NRR) as high as 9.5kgN / (m 3 ·d). In addition, the promotion of the 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 the engineering application shows a booming development trend.

[0078] The technical solution provided by the present invention is as follows:

[0079] The present invention provides a method for treating high-concentration wastewater, and the method for treating high-concentration wastewater includes the following steps:

[0080] Coagulate and precipitate the high-concentration wastewater to be treated, and then perform oxidation treatment to obtain the first wastewater;

[0081] Perform the first hydrolysis reaction treatment, the first anaerobic reaction treatment, and the first aerobic reaction treatment on the first wastewater in sequence to obtain the second wastewater;

[0082] Perform the second hydrolysis reaction treatment, the second anaerobic reaction treatment, and the second aerobic reaction treatment on the second wastewater in sequence to obtain the third wastewater;

[0083] Perform denitrification reaction treatment on the third wastewater, and then perform sludge-water separation treatment to obtain the treated effluent;

[0084] Among them, the physicochemical property parameters of the high-concentration wastewater to be treated include: chemical oxygen demand > 20000 mg / L, total nitrogen content > 3000 mg / L, and salt content > 5000 mg / L;

[0085] The oxidation treatment method is the persulfate advanced oxidation method;

[0086] Both the first anaerobic reaction treatment and the second anaerobic reaction treatment are carried out by using a folded-plate anaerobic biological iron fluidized bed, and the folded-plate anaerobic biological iron fluidized bed is a biological fluidized bed component added at the rear end of an anaerobic baffled reactor;

[0087] The denitrification reaction treatment method is the anaerobic ammonium oxidation method.

[0088] The present invention provides a method for treating high-concentration wastewater. The present invention mainly adopts "coagulation precipitation + persulfate advanced oxidation", and then enters the "anaerobic + aerobic + anaerobic ammonium oxidation denitrification" combined process to ensure that the effluent quality of high-concentration wastewater meets the standards stably, and effectively solves the problems such as high operating cost and poor sewage treatment effect existing in the prior art.

[0089] The improved ABR anaerobic baffled reactor in the present invention is as Figure 3A biological fluidized bed is added to the end of the existing ABR anaerobic folded-plate reactor shown (a biological fluidized bed is a structure filled with smaller inert particles such as sand, activated carbon, and coke as carriers in the bed, with the surface of the carriers covered by a biological film. The sewage flows upward at a certain flow rate, making the carrier particles in a fluidized state. The wastewater flows upward through the sand bed, making the carrier layer in a flowing state, thereby increasing the contact area between the biological film and the wastewater per unit time and providing sufficient oxygen, and strengthening the biological treatment process of the wastewater by using the boiling state of the packing), and the improved folded-plate anaerobic reactor shown in Figure 4 is obtained.

[0090] In some specific embodiments, the steps of coagulating and precipitating the high-concentration wastewater to be treated and then performing oxidation treatment to obtain the first wastewater include the following processes:

[0091] The high-concentration wastewater to be treated is introduced into an adjustment tank, and then successively introduced into a coagulation tank containing a coagulant, a flocculation tank containing a flocculant, and a persulfate oxidation tank containing persulfate for treatment to obtain the first wastewater;

[0092] The operating condition parameters of the coagulation tank include: pH is 8 - 12; temperature is 25 - 27 °C; time is 0.5 h; by 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 salts; the iron salts include ferric chloride, ferrous sulfate, ferric sulfate, polyferric sulfate, etc.;

[0093] The operating condition parameters of the flocculation tank include: pH is 8 - 12; temperature is 25 - 27 °C; time is 0.5 h; by 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;

[0094] The operating condition parameters of the persulfate oxidation tank include: pH is 2 - 12; temperature is 25 - 27 °C; time is 0.5 h; by weight percentage, the added weight of the persulfate is 0.16% of the weight of the high-concentration wastewater to be treated.

[0095] In some specific embodiments, the structural schematic diagram of the persulfate oxidation reactor is as shown in Figure 5 shown.

[0096] In some specific embodiments, the steps of successively performing a first hydrolysis reaction treatment, a first anaerobic reaction treatment, and a first aerobic reaction treatment on the first wastewater to obtain the second wastewater include the following processes:

[0097] The first wastewater is successively introduced into a first-stage hydrolysis fluidized bed, a first-stage folded-plate anaerobic bio-iron fluidized bed, and a first-stage aerobic fluidized bed for treatment to obtain the second wastewater;

[0098] Among them, the operating condition parameters of the first-stage hydrolysis fluidized bed include: dissolved oxygen < 1 mg / L, pH is 4 - 7, temperature is 20 - 35 °C, and time is 40 h;

[0099] The operating condition parameters of the first-stage folded-plate anaerobic biological iron fluidized bed include: dissolved oxygen < 0.5 mg / L, pH is 6 - 8, temperature is 20 - 35 °C, and time is 46 h;

[0100] The operating condition parameters of the first-stage aerobic fluidized bed include: dissolved oxygen is 2 - 6 mg / L, pH is 6 - 8, temperature is 20 - 35 °C, and time is 38 h.

[0101] In some specific embodiments, the steps of sequentially performing a second hydrolysis reaction treatment, a second anaerobic reaction treatment, and a second aerobic reaction treatment on the second wastewater to obtain a third wastewater include the following processes:

[0102] The second wastewater is introduced into the intermediate pool 1, and then sequentially introduced into a secondary hydrolysis fluidized bed, a secondary folded-plate anaerobic biological iron fluidized bed, and a secondary aerobic fluidized bed for treatment to obtain the third wastewater;

[0103] The operating condition parameters of the secondary hydrolysis fluidized bed are the same as those of the first-stage hydrolysis fluidized bed;

[0104] The operating condition parameters of the secondary folded-plate anaerobic biological iron fluidized bed are the same as those of the first-stage folded-plate anaerobic biological iron fluidized bed;

[0105] The operating condition parameters of the secondary aerobic fluidized bed are the same as those of the first-stage aerobic fluidized bed.

[0106] In some specific embodiments, the steps of performing a denitrification reaction treatment on the third wastewater and then performing a mud-water separation treatment to obtain the treated effluent include the following processes:

[0107] The third wastewater is introduced into the intermediate pool 2, and then sequentially introduced into an anaerobic ammonium oxidation pool for denitrification reaction and a final sedimentation tank for mud-water separation to obtain the effluent;

[0108] The operating condition parameters of the anaerobic ammonium oxidation pool include: dissolved oxygen < 0.5 mg / L, pH is 6 - 8, temperature is 26 - 35 °C, and time is 8 h;

[0109] The operating condition parameters of the final sedimentation tank include: temperature is 25 - 27 °C, and time is 4 h.

[0110] In some specific embodiments, anaerobic ammonium oxidation in the present invention can be carried out as Figure 2Perform using the anaerobic ammonium oxidation reactor shown; among them, a pH meter is used to measure the pH in the reactor, controlled at 6.8 - 7.2. If it is lower than 6.8, add alkali; if it is higher than 7.2, add acid for adjustment; the water bath thermostat is used to heat the reactor, controlling the temperature in the reactor at 30 - 40 degrees; the stirrer serves 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.

[0111] In some specific embodiments, the method for treating high-concentration wastewater further includes:

[0112] Collect 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 into the sludge thickening tank, and then perform pressure filtration treatment through a sludge filter press together.

[0113] In some specific embodiments, the sludge of the first-stage aerobic fluidized bed and the second-stage aerobic fluidized bed is recycled to the first-stage hydrolysis fluidized bed and the second-stage hydrolysis fluidized bed.

[0114] In some specific embodiments, the supernatant of the sludge thickening tank and the filtrate of the sludge filter press are both recycled to the adjustment tank.

[0115] In some specific embodiments, the physicochemical property parameters of the treated discharged water include: chemical oxygen demand < 10000 mg / L, total nitrogen content < 600 mg / L, and salt content < 4800 mg / L.

[0116] It should be noted that for the raw materials involved in the method for treating high-concentration wastewater provided by the present invention, if there is no special limitation or specific description, commercially available products can be directly used or prepared by oneself according to the preparation process disclosed in the prior art; at the same time, for the operation steps and condition parameters involved, if there is no special limitation or specific description, they can be carried out according to the steps and parameter conditions of the existing wastewater treatment process or using existing equipment, and the present invention document will not elaborate one by one.

[0117] The following further elaborates the present invention in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions noted in the following embodiments are generally determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0118] Example 1

[0119] This example provides a method for treating high-concentration wastewater, as Figure 6 shown, including the following steps:

[0120] The wastewater to be treated is first collected through the sewage pipeline and then enters the regulating tank. The function of the regulating tank is to fully mix the wastewater to achieve the effect of homogenization and equalization of quantity;

[0121] Next, the wastewater in the regulating tank is pumped to the coagulation tank and the flocculation tank by a lift pump. In these two tanks, the pH value of the wastewater is controlled between 8 and 12 by adding acid or alkali; meanwhile, a coagulant (iron salt - ferric chloride) and a flocculant (PAM) are added to the coagulation tank and the flocculation tank and stirred evenly to make the suspended solids in the wastewater coagulate and precipitate. After that, the wastewater enters the persulfate oxidation tank;

[0122] In the persulfate oxidation tank, persulfate is added to break the chains of macromolecular complex organic substances in the wastewater and convert them into small - molecule compounds, thus facilitating subsequent biochemical treatment;

[0123] Subsequently, the wastewater enters the first - stage hydrolysis fluidized bed for hydrolysis reaction. During this process, the dissolved oxygen is controlled below 1 mg / L and the pH value is between 4 and 6;

[0124] Then, the wastewater enters the first - stage folded - plate anaerobic biological iron fluidized bed for anaerobic reaction. In this stage, the dissolved oxygen also needs to be controlled below 0.5 mg / L and the pH value is between 6 and 8;

[0125] Then, the wastewater enters the first - stage aerobic fluidized bed for aerobic reaction. During this process, the dissolved oxygen is controlled between 2 and 6 mg / L and the pH value also remains between 6 and 8;

[0126] Next, the wastewater enters the intermediate water tank 1 for uniform mixing. Subsequently, it is successively treated by the second - stage hydrolysis fluidized bed, the second - stage folded - plate anaerobic biological iron fluidized bed and the second - stage aerobic fluidized bed, and finally enters the intermediate water tank 2; the control parameters of these stages are the same as those of the first - stage treatment;

[0127] The wastewater then enters the anaerobic ammonium oxidation tank for denitrification reaction. During this process, the dissolved oxygen needs to be controlled below 0.5 mg / L and the pH value is between 7 and 8;

[0128] Finally, the wastewater enters the final sedimentation tank for sludge - water separation. The separated sludge is filtered by a filter press and then transported out for disposal, while the wastewater is finally discharged into the comprehensive sewage treatment station in the factory area for further treatment;

[0129] The sludge generated from the flocculation tank, as well as 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 jointly filtered by the sludge filter press;

[0130] The sludge generated from the first - stage aerobic fluidized bed and the second - stage aerobic fluidized bed is returned to the first - stage hydrolysis fluidized bed and the second - stage hydrolysis fluidized bed to realize the recycling of sludge;

[0131] The supernatant of the sludge thickening tank and the filtrate of the sludge filter press are both refluxed to the regulation tank for subsequent treatment processes.

[0132] The specific operating parameters of each unit in this example are shown in Table 1.

[0133] Table 1 Specific operating parameter table of each unit

[0134]

[0135] Comparative Example 1

[0136] This example provides a method for treating high-concentration wastewater, which is only different from Example 1 in that: the oxidation treatment method in Example 1 is adjusted from the persulfate advanced oxidation method to the Fenton oxidation method, and the Figure 4 shown modified folded plate anaerobic reactor is adjusted to the existing ABR anaerobic folded plate reactor as shown in Figure 3 ; the denitrification reaction treatment method is adjusted from the anaerobic ammonium oxidation method to the AO denitrification process;

[0137] Among them, the working condition parameters of the Fenton oxidation method include: pH is 2 - 4, the reaction temperature is 20 - 40 o °C, the molar ratio of Fe 2+ to the dosage of H2O2: 1:6, and the reaction time is 60 minutes;

[0138] The working condition parameters of the AO denitrification process include: the sludge age is 10 - 30 days, the hydraulic retention time (anaerobic 1.5 h, aerobic 8 h), and the reflux ratio (sludge reflux ratio 80%; mixed liquor reflux ratio 200%).

[0139] Comparative Example 2

[0140] This example provides a method for treating high-concentration wastewater, which is only different from Example 1 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 in Comparative Example 1.

[0141] Comparative Example 3

[0142] This example provides a method for treating high-concentration wastewater, which is only different from Example 1 in that: the Figure 4 shown modified folded plate anaerobic reactor is adjusted to the existing ABR anaerobic folded plate reactor as shown in Figure 3 .

[0143] Comparative Example 4

[0144] This example provides a method for treating high-concentration wastewater, which is only different from Example 1 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.

[0145] For the same composition of the high-concentration wastewater to be treated and meeting the same effluent standards, calculated based on 10 tons of the wastewater to be treated, the operating costs of Example 1 and Comparative Examples 1 to 4 are shown in Table 2.

[0146] Table 2 Operating cost table of Example 1 and Comparative Examples 1 to 4

[0147]

[0148] The various embodiments of the present invention may exist 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 construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has 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., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, and this applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0149] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can 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 these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for treating high-concentration wastewater, characterized in that, The treatment method for the high-concentration wastewater includes the following steps: Coagulate and precipitate the high-concentration wastewater to be treated, and then perform oxidation treatment to obtain the first wastewater; Successively perform a first hydrolysis reaction treatment, a first anaerobic reaction treatment, and a first aerobic reaction treatment on the first wastewater to obtain the second wastewater; Successively perform a second hydrolysis reaction treatment, a second anaerobic reaction treatment, and a second aerobic reaction treatment on the second wastewater to obtain the third wastewater; Perform a denitrification reaction treatment on the third wastewater, and then perform sludge-water separation treatment to obtain the treated discharge water; Among them, the physical and chemical property parameters of the high-concentration wastewater to be treated include: chemical oxygen demand > 20000 mg / L, total nitrogen content > 3000 mg / L, and salt content > 5000 mg / L; The oxidation treatment method is the persulfate advanced oxidation method; Both the first anaerobic reaction treatment and the second anaerobic reaction treatment are carried out using a corrugated anaerobic bio-iron fluidized bed, and the corrugated anaerobic bio-iron fluidized bed is a biological fluidized bed component added at the rear end of an anaerobic baffled reactor; The denitrification reaction treatment method is the anaerobic ammonium oxidation method.

2. The treatment method of high-concentration wastewater according to claim 1, wherein, The step of coagulating and precipitating the high-concentration wastewater to be treated and then performing oxidation treatment to obtain the first wastewater includes the following process: Feed the high-concentration wastewater to be treated into an adjustment tank, and then successively feed it into a coagulation tank containing a coagulant, a flocculation tank containing a flocculant, and a persulfate oxidation tank containing persulfate for treatment to obtain the first wastewater; The operating condition parameters of the coagulation tank include: pH is 8 - 12; temperature is 25 - 27 °C; time is 0.5 h; calculated by 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 salts; The operating condition parameters of the flocculation tank include: pH is 8 - 12; temperature is 25 - 27 °C; time is 0.5 h; calculated by 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 is 2 - 12; temperature is 25 - 27 °C; time is 4 h; calculated by weight percentage, the added weight of the persulfate is 0.16% of the weight of the high-concentration wastewater to be treated.

3. The treatment method for high-concentration wastewater according to claim 2, wherein The step of successively performing a first hydrolysis reaction treatment, a first anaerobic reaction treatment, and a first aerobic reaction treatment on the first wastewater to obtain the second wastewater includes the following process: Feed the first wastewater successively into a first-stage hydrolysis fluidized bed, a first-stage corrugated anaerobic bio-iron fluidized bed, and a first-stage aerobic fluidized bed for treatment to obtain the second wastewater; Among them, the operating condition parameters of the first-stage hydrolysis fluidized bed include: dissolved oxygen < 1 mg / L, pH is 4 - 7, temperature is 20 - 35 °C, time is 40 h; The operating condition parameters of the first-stage corrugated anaerobic bio-iron fluidized bed include: dissolved oxygen < 0.5 mg / L, pH is 6 - 8, temperature is 20 - 35 °C, time is 46 h; The operating conditions and parameters of the first aerobic fluidized bed include: dissolved oxygen of 2 - 6 mg / L, pH of 6 - 8, temperature of 20 - 35 °C, and time of 38 h.

4. The treatment method of high-concentration wastewater according to claim 3, characterized in that, The steps of 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 include the following processes: The second wastewater is introduced into the intermediate pool (1), and then successively introduced into a secondary hydrolysis fluidized bed, a secondary corrugated plate anaerobic bio - iron fluidized bed, and a secondary aerobic fluidized bed for treatment to obtain the third wastewater; The operating conditions and parameters of the secondary hydrolysis fluidized bed are the same as those of the first hydrolysis fluidized bed; The operating conditions and parameters of the secondary corrugated plate anaerobic bio - iron fluidized bed are the same as those of the first corrugated plate anaerobic bio - iron fluidized bed; The operating conditions and parameters of the secondary aerobic fluidized bed are the same as those of the first aerobic fluidized bed.

5. The treatment method of high-concentration wastewater according to claim 4, characterized in that The steps of subjecting the third wastewater to a denitrification reaction treatment and then a sludge - water separation treatment to obtain the treated effluent for discharge include the following processes: The third wastewater is introduced into the intermediate pool (2), and then successively introduced into an anaerobic ammonium oxidation pool for denitrification reaction and a final sedimentation tank for sludge - water separation to obtain the effluent for discharge; The operating conditions and parameters of the anaerobic ammonium oxidation pool include: dissolved oxygen < 0.5 mg / L, pH of 6 - 8, temperature of 26 - 35 °C, and time of 8 h; The operating conditions and parameters of the final sedimentation tank include: temperature of 25 - 27 °C, and time of 4 h.

6. The treatment method of high-concentration wastewater according to claim 5, characterized in that, The treatment method for the high - concentration wastewater further includes: The sludge from the flocculation tank, the first corrugated plate anaerobic bio - iron fluidized bed, the second corrugated plate anaerobic bio - iron fluidized bed, and the final sedimentation tank is collected in a sludge thickening tank and then filtered by a sludge filter press together.

7. The treatment method of high-concentration wastewater according to claim 6, characterized in that, The sludge from the first aerobic fluidized bed and the second aerobic fluidized bed is respectively recycled to the first hydrolysis fluidized bed and the second hydrolysis fluidized bed.

8. The treatment method for 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 recycled to the adjustment tank.

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

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