Hydrolytic acidification treatment process for industrial wastewater

Abstract

The application discloses a kind of industrial wastewater hydrolysis acidification treatment process, belong to industrial wastewater treatment technical field.For the problems such as traditional process packing is easy to wear and powder, pool body is easy to be corroded and seep, single function of flora, low treatment efficiency and unstable operation, the process is sequentially through wastewater pretreatment, hydrolysis acidification pool lays anti-permeation wear-resistant lining and fills modified wear-resistant and anti-permeation composite packing, inoculates composite hydrolysis acidification bacterial agent to complete biofilm cultivation, four stages of upflow continuous operation.Suitably developed modified packing has high wear resistance and anti-permeation performance, composite bacterial agent multiple species function complementary synergistic degradation, anti-permeation lining can resist wastewater corrosion and water flow scour, three synergies and match optimized operating parameters, can effectively improve wastewater biodegradability, prolong system service life, reduce operating cost, suitable for multiple industries difficult-to-degrade industrial wastewater pretreatment.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment technology, specifically relating to a hydrolysis acidification treatment process for industrial wastewater. Background Technology

[0002] Hydrolysis-acidification is one of the most widely used pretreatment units in biological wastewater treatment systems. Its core principle is to control the anaerobic reaction process, stopping the reaction at the hydrolysis and acidification stages. Extracellular enzymes decompose large molecules and recalcitrant organic matter in the wastewater into smaller, soluble organic molecules. These soluble organic molecules are then converted into easily biodegradable substances such as volatile fatty acids and alcohols by acid-producing bacteria, significantly improving the wastewater's biodegradability. This reduces the load on subsequent aerobic biological treatment units and enhances treatment efficiency. This process boasts advantages such as low energy consumption, strong resistance to shock loads, wide applicability to various wastewater types, and low sludge production. It has been widely applied in industrial wastewater treatment projects across multiple industries, including chemical, printing and dyeing, pharmaceutical, food processing, and papermaking.

[0003] With the development of industrial production technology, the composition of industrial wastewater is becoming increasingly complex, and the concentration of pollutants is constantly increasing. Traditional hydrolysis acidification processes have gradually revealed many shortcomings in practical engineering applications, making it difficult to meet increasingly stringent environmental protection requirements. Specific problems are as follows:

[0004] First, hydrolysis acidification tanks often employ an upflow inlet design, subjecting the packing material to continuous scouring by the rising water flow. Simultaneously, constant friction and collision occur between the particles. Traditional packing materials such as ordinary clay ceramsite, coke, and polypropylene plastic packing have poor wear resistance, and after 1-2 years of operation, they exhibit wear, breakage, and pulverization. This not only requires frequent packing replenishment, increasing operating and maintenance costs, but the fine particles generated from breakage also flow out with the effluent, increasing the suspended solids load in subsequent treatment units and even causing pipe blockages. Some projects have attempted to use hard ceramic packing to improve wear resistance, but this suffers from low porosity, small specific surface area, and poor biofilm formation, ultimately reducing treatment efficiency.

[0005] Secondly, industrial wastewater commonly contains corrosive components such as acids, alkalis, organic solvents, and heavy metal ions. Traditional reinforced concrete tanks, treated only with cement mortar plastering, are prone to corrosion cracking and structural loosening after long-term contact with corrosive wastewater, leading to wastewater leakage and pollution of soil and groundwater. Existing improvement solutions mostly use ordinary epoxy coatings for seepage prevention, but ordinary epoxy coatings have poor wear resistance and are easily peeled off and damaged under long-term scouring by filler and water flow, losing their seepage prevention function in a short time and failing to fundamentally solve the problem of tank corrosion and leakage.

[0006] Third, traditional hydrolysis acidification processes largely rely on naturally attached biofilm culture of indigenous microorganisms. The microbial community structure is highly susceptible to influent water quality, resulting in low levels and limited variety of functional bacteria. This leads to weak degradation capabilities for high concentrations of recalcitrant aromatic and heterocyclic organic compounds, low COD removal rates, and limited improvement in the effluent B / C ratio, making it difficult to fully realize the pretreatment value of hydrolysis acidification. Some studies have attempted to enhance treatment effects by adding single hydrolytic bacterial agents; however, the functions of single bacterial species are limited, failing to cover all types of pollutants in complex wastewater. Furthermore, the lack of synergistic effects between bacterial species results in unstable treatment effects and poor resistance to shock loads.

[0007] Fourth, the existing process relies heavily on engineering experience to set operating parameters such as hydraulic retention time, upward flow velocity, and dissolved oxygen, without coordinating optimization with the characteristics of the packing material and the bacterial agent. This can easily lead to problems such as excessively high upward flow velocity causing sludge loss, insufficient hydraulic retention time leading to incomplete acidification, and improper dissolved oxygen control affecting the activity of anaerobic bacteria. As a result, the treatment effect fluctuates greatly and the system has weak shock resistance.

[0008] In summary, the field of industrial wastewater hydrolysis and acidification treatment urgently needs a new process that can simultaneously solve multiple problems such as packing wear, tank leakage, low treatment efficiency, and unstable operation, and achieve multiple technical effects such as wear resistance, seepage prevention, high-efficiency degradation, and stable operation. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide an industrial wastewater hydrolysis acidification treatment process. By combining modified wear-resistant and seepage-resistant composite packing, seepage-proof and wear-resistant tank lining, and composite hydrolysis acidification bacteria agent, and with optimized process operating parameters, the invention systematically solves the problems of easy wear of packing, easy leakage of tank, low treatment efficiency, and unstable operation in traditional processes, and significantly improves the comprehensive performance and engineering application value of the hydrolysis acidification process.

[0010] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0011] An industrial wastewater hydrolysis acidification treatment process includes the following steps:

[0012] S1 Wastewater Pretreatment: After removing large particulate suspended solids from industrial wastewater through a screen, the wastewater enters an equalization tank to adjust the water quality and quantity, controlling the influent pH to 6.0-7.5 and the water temperature to 25-35℃.

[0013] Preparation of S2 hydrolysis acidification tank: Lay a seepage-proof and wear-resistant lining on the inner wall of the hydrolysis acidification tank, and fill the tank with modified wear-resistant and seepage-proof composite filler, with a filler filling rate of 30%-50%;

[0014] S3 bacterial agent inoculation and biofilm formation: Inoculate the compound hydrolysis acidification bacterial agent into the hydrolysis acidification tank. The inoculation amount is 8%-12% of the effective volume of the tank. Carry out the biofilm formation culture for 7-10 days until the biofilm thickness on the packing surface reaches 1-2 mm.

[0015] S4 Continuous Operation Treatment: The adjusted wastewater is introduced into the hydrolysis acidification tank in an upflow manner, with the hydraulic retention time controlled at 8-16 hours, the upflow velocity at 0.5-1.2 m / h, and the dissolved oxygen in the tank controlled below 0.2 mg / L to complete the hydrolysis acidification treatment.

[0016] Furthermore, the modified wear-resistant and impermeable composite filler comprises the following components by weight: 40-60 parts clay, 10-20 parts silicon carbide micro powder, 8-15 parts epoxy resin modified kaolin, 5-12 parts fly ash, 3-8 parts starch pore-forming agent, 1-3 parts silane coupling agent, and 15-25 parts deionized water.

[0017] Furthermore, the silicon carbide micro powder has a particle size of 200-400 mesh and a Mohs hardness ≥9.2; the preparation method of the epoxy resin modified kaolin is as follows: the kaolin is dried at 120℃ for 2h to remove free water, and then 5%-10% of epoxy resin E-44 by mass of kaolin is added. The mixture is stirred at high speed at 1200r / min for 15min to mix evenly. Then it is placed in an 80℃ oven for curing for 4h. After being taken out, it is ground by ball mill and passed through a 200-mesh sieve to obtain the final product.

[0018] Furthermore, the preparation method of the modified wear-resistant and impermeable composite filler includes the following steps:

[0019] W1 Powder Mixing: Accurately weigh clay, silicon carbide micro powder, epoxy resin modified kaolin, and fly ash according to the mass ratio, add them to a planetary ball mill, control the ball-to-material ratio to be 2:1, and ball mill at a speed of 300 r / min for 30-60 min to ensure that the components are fully ground and mixed evenly to obtain a mixed powder.

[0020] W2 clay preparation: Transfer the mixed powder to a vacuum kneader, add the weighed starch pore-forming agent and silane coupling agent, dry mix for 10 minutes to evenly disperse the powder, then add deionized water in three equal portions, kneading for 10 minutes after each addition of water, and finally obtain a uniform plastic clay with a moisture content controlled at 18%-22%;

[0021] W3 Extrusion Granulation: The mud material is added to the twin-screw extruder and extruded into strips of mud material with a diameter of 8-12mm. The strips are then cut into equal-length particles by a pelletizer and processed into spherical particles by a rounding machine. The particle size tolerance is controlled within ±1mm.

[0022] W4 Air Drying: Spread the formed granules flat on a breathable tray and place them in a cool, ventilated place to air dry for 24 hours. Turn them over every 6 hours during this period to prevent the granules from deforming and cracking due to uneven drying. After air drying, the moisture content of the granules will drop to below 10%.

[0023] W5 program sintering: The air-dried granules are placed in a muffle furnace and sintered according to the set heating program: the temperature is increased from room temperature to 600℃ at a rate of 3℃ / min, and held for 1 hour to allow the starch pore-forming agent to fully pyrolyze and form pores; then the temperature is increased to 1050-1150℃ at a rate of 5℃ / min, and held for 2-3 hours to allow the clay to vitrify and the components to fully sinter and bond together; after sintering, the furnace is naturally cooled to room temperature to obtain the filler matrix;

[0024] W6 Surface Modification: The filler matrix is ​​immersed in a 5% (w / w) silane coupling agent KH-550 ethanol solution, with the liquid level 5cm above the filler. It is soaked at room temperature for 2 hours, and stirred twice during the soaking to ensure uniform soaking. After soaking, it is taken out and drained, and then placed in a 105℃ forced-air drying oven to dry for 1 hour, so that the coupling agent and the filler surface can form a chemical bond, thus obtaining a modified wear-resistant and impermeable composite filler.

[0025] Further, the compound hydrolyzing acidifying bacterial agent, by volume, comprises: 20-30 parts of Clostridium butyricum fermentation broth, 15-25 parts of Vibrio acetophilia desulfurizing broth, 15-20 parts of hydrogen-producing and acetic acid-producing bacteria broth, 10-20 parts of Lactobacillus spp. , and 5-12 parts of white-rot fungal broth, with each individual bacterial broth having a concentration of 1.0 × 10⁻⁶. 8 -1.0×10 9 CFU / mL.

[0026] Further, the preparation method of the compound hydrolyzed acidifying bacterial agent is as follows: add each single bacterial solution to a sterile mixing tank in proportion and stir at low speed until uniform; then add a nutrient protectant at a mass of 2%-5% of the total mass of the mixed bacterial solution, and continue stirring for 10 minutes; seal the mixing tank and activate and culture in an anaerobic environment at 25°C for 24 hours to allow each bacterial strain to adapt to the mixing system and restore its activity, thus obtaining the compound hydrolyzed acidifying bacterial agent; the nutrient protectant includes, by mass, 10 parts glucose, 5 parts peptone, 2 parts potassium dihydrogen phosphate, and 0.5 parts magnesium sulfate.

[0027] Furthermore, the seepage-proof and wear-resistant lining is made of the following components by weight: 0-45 parts epoxy resin E-513, 10-18 parts curing agent polyamide 650, 5-10 parts silicon carbide whiskers, 8-15 parts mica powder, 0.3-0.8 parts defoamer BYK-066N, and 3-8 parts diluent acetone.

[0028] Furthermore, the construction method for the impermeable and wear-resistant lining is as follows:

[0029] X1 Base Treatment: Thoroughly clean the floating dust, oil stains, and loose layers from the inner wall of the hydrolysis acidification tank concrete, grind it smooth with an angle grinder, and repair and level any depressions with epoxy mortar; rinse the base surface with a high-pressure water gun, and after it is completely dry, apply epoxy primer. The primer is made by diluting epoxy resin E-51 and acetone at a mass ratio of 1:1, with a dosage of 0.2 kg / m², to enhance the adhesion between the coating and the concrete base surface;

[0030] X2 Coating Preparation: Weigh epoxy resin E-51, silicon carbide whiskers, mica powder, and defoamer according to the mass ratio, add them to a high-speed disperser, and disperse at 800 r / min for 20 min to ensure that the functional filler is evenly dispersed in the resin matrix; add acetone as a diluent to adjust the viscosity of the system, and continue to disperse for 5 min; before construction, add polyamide 650 as a curing agent, stir evenly, and let stand for 10 min to defoam;

[0031] X3 Scraping Application: Apply the coating in 2-3 coats using a scraper. The first coat should be approximately 0.8mm thick. After it is surface dry (approximately 12 hours), apply the second coat. If necessary, apply the third coat. The final total thickness should be controlled between 1.5-2.5mm. During the application process, ensure that the coating is uniform and continuous, without any defects such as missed areas, runs, or pinholes.

[0032] X4 Curing and Maintenance: After construction, cure at room temperature for 72 hours. Once the coating has fully cured and cross-linked, it can be put into use.

[0033] Furthermore, in step S1, for industrial wastewater with high suspended solids content, the pretreatment also includes adding polyaluminum chloride with a mass concentration of 50-100 mg / L to the equalization tank, first stirring rapidly at 200 r / min for 15 min, then stirring slowly at 50 r / min for 5 min, and then allowing it to settle for 30 min to remove some suspended solids and colloidal substances, thereby reducing the load on the subsequent hydrolysis acidification tank.

[0034] Furthermore, in step S4, during the operation of the hydrolysis acidification tank, sludge is returned every 15 days with a return ratio of 10%-20%. The returned sludge is taken from the remaining sludge in the subsequent secondary sedimentation tank and is used to replenish the amount of microorganisms in the tank, maintain the stability of the system's biological concentration, and improve its resistance to shock loads.

[0035] The beneficial effects of this invention are:

[0036] (1) This invention uses clay as the matrix and introduces high-hardness silicon carbide micro powder as the wear-resistant reinforcing phase, which is uniformly dispersed in the filler matrix to form a wear-resistant skeleton, significantly improving the hardness and wear resistance of the filler and greatly reducing the breakage loss caused by water flow scouring and particle friction; at the same time, epoxy resin modified kaolin is added to form a dense glass phase during high-temperature sintering, which fills the interconnected pores inside the filler, blocks the seepage path, significantly improves the anti-seepage and anti-corrosion performance of the filler, avoids wastewater seeping into the filler and corroding the matrix, effectively extends the service life of the filler, and greatly reduces the operation and maintenance costs.

[0037] (2) The epoxy resin-based anti-seepage and wear-resistant lining developed in this invention uses epoxy resin as the film-forming material to form a dense anti-seepage barrier, which can effectively block the corrosion of concrete tanks by corrosive components such as acids, alkalis, organic solvents, and heavy metals in wastewater; the addition of flake mica powder extends the penetration path and further improves the anti-seepage and anti-corrosion effect; the introduction of silicon carbide whiskers as wear-resistant reinforcing phase greatly improves the hardness and erosion resistance of the coating, which can resist the long-term wear of filler particles and water flow, avoid the problem of easy peeling of traditional epoxy coatings, ensure the long-term stable operation of the tank, and fundamentally solve the hidden danger of wastewater leakage and pollution.

[0038] (3) This invention combines five different hydrolytic acidifying microorganisms with complementary functions to form a microbial community system: Clostridium butyricum and Lactobacillus are responsible for the hydrolysis of macromolecular organic matter such as polysaccharides and proteins; hydrogen-producing acetic acid bacteria and acetic acid desulfurizing Vibrio are responsible for converting intermediate products into volatile fatty acids, completing the acidification process; white-rot fungi can secrete ligninase, laccase, etc., to degrade recalcitrant aromatic and heterocyclic organic matter in wastewater. Each microbial species has a clear division of labor and works synergistically, which can efficiently treat complex industrial wastewater with high COD removal rate, effectively improve the B / C ratio of effluent, significantly improve the biodegradability of wastewater, and create favorable conditions for subsequent biochemical treatment.

[0039] (4) Based on the characteristics of modified packing and composite bacterial agent, this invention optimizes and matches process parameters such as hydraulic retention time, upflow velocity, dissolved oxygen, and sludge return. It adopts an upflow influent method, which ensures that the wastewater and the biofilm on the surface of the packing are in full contact, while avoiding excessive flow velocity that could cause biofilm detachment and sludge loss. Regular sludge return maintains the biomass of the system, greatly improving the system's resistance to shock loads, and maintaining a stable treatment effect even when the influent water quality fluctuates.

[0040] (5) The filler material of the present invention contains industrial solid waste such as fly ash, realizing the resource utilization of solid waste and reducing the cost of raw materials; the process does not require continuous aeration and has low operating energy consumption; the filler and lining have long service life and long maintenance cycle, and the overall operating cost is significantly lower than that of traditional processes, with both good economic and environmental benefits. Detailed Implementation

[0041] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0042] Overall process flow description

[0043] This process is suitable for treating high-concentration, recalcitrant industrial wastewater from industries such as chemical, printing and dyeing, pharmaceutical, and papermaking. The overall process flow is as follows: industrial wastewater, coarse and fine screens, equalization tank, upflow hydrolysis acidification tank, and subsequent aerobic biochemical treatment unit.

[0044] 1. Bar screen treatment: Industrial wastewater first passes through a coarse bar screen (10-20mm spacing) to remove large floating and suspended solids, and then through a fine bar screen (3-5mm spacing) to remove fine fibers and particulate impurities, preventing blockage of subsequent pipes and water distribution systems.

[0045] 2. Equalization Tank Treatment: Water effluent from the screen enters the equalization tank, where a submersible mixer continuously agitates the water to achieve homogenization and buffer fluctuations in influent quality and quantity. Depending on the influent quality, sodium hydroxide or sulfuric acid is added to adjust the pH to 6.0-7.5. The water temperature is adjusted to 25-35℃ using a steam heat exchanger or cooling system to provide a suitable growth environment for microorganisms. When the suspended solids concentration is >300mg / L, 50-100mg / L polyaluminum chloride is added for coagulation and sedimentation to remove some suspended solids and colloids, reducing the load on subsequent units.

[0046] 3. Hydrolysis Acidification Tank Treatment: The regulated wastewater is pumped into the bottom of the hydrolysis acidification tank via a lift pump. Water is evenly distributed through a perforated water distribution system, flowing upwards through the packing layer and fully contacting the biofilm attached to the packing surface. Under the action of anaerobic microorganisms, the hydrolysis acidification reaction is completed. The treated wastewater flows out through an overflow weir at the top of the tank and enters the subsequent biological treatment unit. The hydrolysis acidification tank is a reinforced concrete structure with an impermeable and wear-resistant lining on the inner wall. The tank is filled in layers with modified wear-resistant and impermeable composite packing, with supporting grids between the layers. A three-phase separator is installed at the top of the tank to separate biogas, wastewater, and sludge.

[0047] 4. Sludge return system: During system operation, sludge return is carried out every 15 days, and the concentrated excess sludge from the subsequent secondary sedimentation tank is returned to the inlet of the hydrolysis acidification tank. The return ratio is controlled at 10%-20% to replenish the microorganisms lost by the system and maintain the stability of biomass in the tank.

[0048] Construction instructions for waterproof and wear-resistant lining

[0049] X1 Base Treatment: Thoroughly clean the floating dust, oil stains, and loose layers from the inner wall of the hydrolysis acidification tank concrete, grind it smooth with an angle grinder, and repair and level any depressions with epoxy mortar; rinse the base surface with a high-pressure water gun, and after it is completely dry, apply epoxy primer. The primer is made by diluting epoxy resin E-51 and acetone at a mass ratio of 1:1, with a dosage of 0.2 kg / m², to enhance the adhesion between the coating and the concrete base surface;

[0050] X2 Coating Preparation: Weigh epoxy resin E-51, silicon carbide whiskers, mica powder, and defoamer according to the mass ratio, add them to a high-speed disperser, and disperse at 800 r / min for 20 min to ensure that the functional filler is evenly dispersed in the resin matrix; add acetone as a diluent to adjust the viscosity of the system, and continue to disperse for 5 min; before construction, add polyamide 650 as a curing agent, stir evenly, and let stand for 10 min to defoam;

[0051] X3 Scraping Application: Apply the coating in 2-3 coats using a scraper. The first coat should be approximately 0.8mm thick. After it is surface dry (approximately 12 hours), apply the second coat. If necessary, apply the third coat. The final total thickness should be controlled between 1.5-2.5mm. During the application process, ensure that the coating is uniform and continuous, without any defects such as missed areas, runs, or pinholes.

[0052] X4 Curing and Maintenance: After construction, cure at room temperature for 72 hours. Once the coating has fully cured and cross-linked, it can be put into use.

[0053] Example 1

[0054] This embodiment provides a hydrolysis acidification treatment process for industrial wastewater, and the specific preparation and operation process is as follows:

[0055] 1. Preparation of modified wear-resistant and impermeable composite fillers

[0056] Raw materials by weight: 50 parts clay, 15 parts silicon carbide micro powder, 10 parts epoxy resin modified kaolin, 8 parts fly ash, 5 parts starch pore-forming agent, 2 parts silane coupling agent KH-550, and 20 parts deionized water.

[0057] The clay is a composite clay made of bentonite and kaolin mixed in a mass ratio of 2:1, with a plasticity index of 18; the silicon carbide powder is 200-mesh black silicon carbide with a Mohs hardness of 9.5; the epoxy resin modified kaolin contains 8% E-44 epoxy resin by mass of kaolin; the fly ash is secondary fly ash with a 15% residue on a 0.045mm square hole sieve; and the starch pore-forming agent is 100-mesh corn starch.

[0058] Preparation steps:

[0059] W1 weighs clay, silicon carbide micro powder, epoxy resin modified kaolin, and fly ash according to the formula, adds them to a planetary ball mill, ball-to-material ratio 2:1, and ball mills at 300 r / min for 45 min to obtain a uniformly mixed powder.

[0060] W2 mixed powder was transferred to a vacuum kneader, starch pore-forming agent and silane coupling agent were added and dry-mixed for 10 minutes, deionized water was added in 3 batches, kneading for 10 minutes each time, to obtain plastic clay with a moisture content of 20%.

[0061] W3 mud material is fed into a twin-screw extruder and granulator, extruding strips with a diameter of 10mm. After being cut into pellets, the strips are rolled into spherical particles.

[0062] W4 granules are laid flat and air-dried for 24 hours, turning them over every 6 hours.

[0063] W5 muffle furnace sintering program: heat up to 600℃ at 3℃ / min and hold for 1h, heat up to 1100℃ at 5℃ / min and hold for 2.5h, then cool naturally with the furnace to obtain the filler matrix;

[0064] The W6 packing matrix was immersed in a 5% KH-550 ethanol solution for 2 hours, then removed and dried at 105℃ for 1 hour to obtain a modified wear-resistant and impermeable composite packing.

[0065] 2. Preparation of compound hydrolyzed acidifying bacterial agent

[0066] Raw materials by volume: 25 parts of Clostridium butyricum fermentation liquid, 20 parts of Vibrio acetoxyphylla desulfurization liquid, 18 parts of hydrogen-producing and acetic acid-producing bacteria liquid, 15 parts of Lactobacillus liquid, and 8 parts of white rot fungus liquid.

[0067] The concentration of each single bacterial culture was approximately 5.0 × 10⁻⁶. 8 The concentration of CFU / mL was 8 g / L, with the white-rot fungus being *Procambarus chrysospora*.

[0068] Preparation steps: Add each single bacterial culture to a sterile mixing tank in proportion and stir at low speed until uniform; add 3% of the total mass of the mixed bacterial culture with a nutrient protectant (10 parts glucose, 5 parts peptone, 2 parts potassium dihydrogen phosphate, and 0.5 parts magnesium sulfate), stir for 10 min; seal and anaerobic activate at 25℃ for 24 h to obtain the composite hydrolyzed acidifying bacterial agent.

[0069] 3. Preparation and construction of impermeable and wear-resistant inner lining

[0070] Raw materials by weight: 38 parts epoxy resin E-5, 14 parts polyamide 650, 8 parts silicon carbide whiskers, 12 parts mica powder, 0.5 parts defoamer BYK-066N, and 5 parts acetone.

[0071] The silicon carbide whiskers have a diameter of 0.5-1μm and a length of 10-50μm; the mica powder is 800-mesh sericite powder.

[0072] Construction steps: Grind and clean the concrete base surface to make it smooth, and apply epoxy primer; prepare the coating according to the ratio, apply it in 2 coats, with a total thickness of 2mm; cure at room temperature for 72 hours.

[0073] 4. Process Operation

[0074] The wastewater being treated is comprehensive industrial wastewater from a chemical industrial park. The influent water quality is as follows: COD 2500 mg / L, BOD 5500 mg / L, B / C ratio 0.2, SS 300 mg / L, pH 6.8, and water temperature 28℃.

[0075] S1 Pretreatment: Wastewater enters the equalization tank after passing through coarse and fine screens, and 80 mg / L polyaluminum chloride is added. After coagulation and sedimentation, the pH is adjusted to 6.8 and the water temperature is stabilized at 28℃.

[0076] Preparation of S2 hydrolysis acidification tank: The inner wall of the tank is lined with the above-mentioned seepage-proof and wear-resistant lining, and filled with modified filler with a filler filling rate of 40%;

[0077] S3 Inoculation and Biofilm Formation: Inoculate with compound hydrolyzed acidifying bacteria at a rate of 10% of the effective volume of the tank. Use intermittent water intake and aeration for 8 days to form a uniform biofilm on the surface of the packing material with a thickness of about 1.5 mm.

[0078] S4 Continuous Operation: Upflow continuous water intake is adopted, with a hydraulic retention time of 12 hours, an upflow velocity of 0.8 m / h, and dissolved oxygen in the tank controlled below 0.1 mg / L; sludge is returned once every 15 days with a return ratio of 15%.

[0079] Example 2

[0080] This embodiment provides an industrial wastewater hydrolysis acidification treatment process. The difference from Embodiment 1 is that the ratio of packing material, bacterial agent, and lining, as well as the process parameters, are all set at a high dosage, as detailed below:

[0081] 1. Preparation of modified wear-resistant and impermeable composite fillers

[0082] Raw materials by weight: 40 parts clay, 20 parts silicon carbide powder, 15 parts epoxy resin modified kaolin, 12 parts fly ash, 8 parts starch pore-forming agent, 3 parts silane coupling agent KH-550, and 25 parts deionized water.

[0083] In epoxy resin modified kaolin, the amount of epoxy resin added is 10% of the mass of kaolin.

[0084] Preparation steps: ball milling time 60 min, sintering temperature 1150℃, holding time 3 h, the remaining steps and parameters are the same as in Example 1, and the final filler particle size is 12 mm.

[0085] 2. Preparation of compound hydrolyzed acidifying bacterial agent

[0086] Raw materials by volume: 30 parts of Clostridium butyricum fermentation liquid, 25 parts of Vibrio acetoxyphylla desulfurization liquid, 20 parts of Lactobacillus fermentation liquid, and 12 parts of white rot fungus fermentation liquid.

[0087] The preparation method is the same as in Example 1.

[0088] 3. Preparation of seepage-proof and wear-resistant inner lining

[0089] Raw materials by weight: 145 parts epoxy resin E-5, 18 parts polyamide 650, 10 parts silicon carbide whiskers, 15 parts mica powder, 0.8 parts defoamer, and 8 parts acetone.

[0090] The total thickness of the construction is 2.5mm, and the rest is the same as in Example 1.

[0091] 4. Process Operation

[0092] The chemical wastewater treated in the same manner as in Example 1 was treated with a packing filler rate of 50%, a bacterial inoculum amount of 12%, a biofilm culture period of 10 days, a hydraulic retention time of 16 hours, an upward flow velocity of 1.2 m / h, a sludge return ratio of 20%, and other parameters being the same as in Example 1.

[0093] Example 3

[0094] This embodiment provides an industrial wastewater hydrolysis acidification treatment process. The difference from Embodiment 1 is that the ratio of packing material, bacterial agent, and lining, as well as the process parameters, are all set at low dosages, as detailed below:

[0095] 1. Preparation of modified wear-resistant and impermeable composite fillers

[0096] Raw materials by weight: 60 parts clay, 10 parts silicon carbide powder, 8 parts epoxy resin modified kaolin, 5 parts fly ash, 3 parts starch pore-forming agent, 1 part silane coupling agent KH-550, and 15 parts deionized water.

[0097] In epoxy resin modified kaolin, the amount of epoxy resin added is 5% of the mass of kaolin.

[0098] Preparation steps: ball milling time 30 min, sintering temperature 1050℃, holding time 2 h, the remaining steps and parameters are the same as in Example 1, and the final filler particle size is 8 mm.

[0099] 2. Preparation of compound hydrolyzed acidifying bacterial agent

[0100] Raw materials by volume: 20 parts of Clostridium butyricum fermentation liquid, 15 parts of Vibrio acetoxyphylla desulfurizing liquid, 15 parts of Lactobacillus fermentation liquid, and 5 parts of white rot fungus liquid.

[0101] The preparation method is the same as in Example 1.

[0102] 3. Preparation of seepage-proof and wear-resistant inner lining

[0103] Raw materials by weight: 130 parts epoxy resin E-5, 10 parts polyamide 650, 5 parts silicon carbide whiskers, 8 parts mica powder, 0.3 parts defoamer, and 3 parts acetone.

[0104] The total thickness of the construction is 1.5mm, and the rest is the same as in Example 1.

[0105] 4. Process Operation

[0106] The chemical wastewater treated in the same manner as in Example 1 was treated with a packing filler rate of 30%, a bacterial inoculum amount of 8%, a biofilm culture period of 7 days, a hydraulic retention time of 8 hours, an upward flow velocity of 0.5 m / h, a sludge return ratio of 10%, and other parameters being the same as in Example 1.

[0107] Comparative Example 1

[0108] The modified filler does not contain silicon carbide micro powder, but is replaced with clay of equal mass. The other raw materials, preparation methods and process parameters are the same as in Example 1.

[0109] Comparative Example 2

[0110] The modified filler does not contain epoxy resin-modified kaolin; instead, it is replaced with an equal mass of ordinary kaolin. All other raw materials, preparation methods, and process parameters are the same as in Example 1.

[0111] Comparative Example 3

[0112] The silicon carbide micro powder in the modified filler was replaced with an equal mass of 200-mesh quartz sand, and the remaining raw materials, preparation methods, and process parameters were the same as in Example 1.

[0113] Comparative Example 4

[0114] The epoxy resin-modified kaolin in the modified filler was replaced with an equal mass of ordinary bentonite, and the remaining raw materials, preparation methods, and process parameters were the same as in Example 1.

[0115] Comparative Example 5

[0116] The compound microbial agent does not contain Vibrio acetoxyphenidobacterium desulfurization liquid; instead, it is replaced with an equal volume of Clostridium butyricum fermentation liquid. The composition, preparation method, and process parameters of the remaining microbial agents are the same as in Example 1.

[0117] Comparative Example 6

[0118] The compound microbial agent does not contain white-rot fungal solution; instead, it is replaced with an equal volume of lactobacillus solution. The composition, preparation method, and process parameters of the remaining microbial agents are the same as in Example 1.

[0119] Comparative Example 7

[0120] The hydraulic residence time was set to 6 hours during process operation, and all other process parameters were the same as in Example 1.

[0121] Comparative Example 8

[0122] The modified packing material of this invention is not used in the hydrolysis acidification tank. Instead, clay ceramsite packing material (Gongyi Xuhong Water Purification Materials Co., Ltd.) is used. All other process parameters are the same as in Example 1.

[0123] Comparative Example 9

[0124] Without inoculating with compound hydrolyzed acidifying bacteria, the biofilm was cultured using a natural biofilm formation method for 30 days. All other process parameters were the same as in Example 1.

[0125] Comparative Example 10

[0126] The inner wall of the hydrolysis acidification tank is not lined with a seepage-proof and wear-resistant lining, but is only treated with ordinary cement mortar plastering. All other process parameters are the same as in Example 1.

[0127] Performance testing

[0128] Test method description

[0129] 1. Performance testing of filler materials

[0130] Abrasion rate: Refer to CJ / T299-2008 "Artificial Ceramsite Filter Media for Water Treatment". Take a dried packing sample, put it into an abrasion tester and rotate it for 1000 revolutions. After sieving through a 1mm sieve, weigh the mass on the sieve and calculate the abrasion rate. The lower the value, the better the abrasion resistance.

[0131] Permeability coefficient: The packing material is pressed into a standard test block, and the permeability coefficient is tested by hydrostatic pressure method. The smaller the value, the better the anti-seepage performance.

[0132] Specific surface area: The specific surface area of ​​the packing material was tested using the BET nitrogen adsorption method.

[0133] 2. Performance testing of lining materials

[0134] Wear resistance: Refer to GB / T1768-2006, Taber wear test, rotate 1000 times under 500g load, and test the wear loss. The smaller the value, the better the wear resistance.

[0135] Corrosion resistance: The coated sample was immersed in simulated industrial wastewater (pH=2 hydrochloric acid + 10% ethanol) for 30 days, and the appearance changes were observed.

[0136] 3. Wastewater treatment performance testing

[0137] After each system has been running continuously and stably for 30 days, influent and effluent water samples were collected for testing. The testing methods were as follows: COD was measured using the potassium dichromate method, BOD5 using the dilution inoculation method, VFA using gas chromatography, and SS using the gravimetric method. Simultaneously, after 6 months of continuous operation, the packing material breakage rate was measured, and the appearance of the lining was observed.

[0138] Test results

[0139] Table 1. Test results of packing and lining materials.

[0140]

[0141]

[0142] Table 2. Wastewater treatment performance test results

[0143]

[0144]

[0145] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process for treating industrial wastewater by hydrolysis and acidification, characterized in that, Includes the following steps: S1 Wastewater Pretreatment: After removing large particulate suspended solids from industrial wastewater through a screen, the wastewater enters an equalization tank to adjust the water quality and quantity, controlling the influent pH to 6.0-7.5 and the water temperature to 25-35℃. Preparation of S2 hydrolysis acidification tank: Lay a seepage-proof and wear-resistant lining on the inner wall of the hydrolysis acidification tank, and fill the tank with modified wear-resistant and seepage-proof composite filler, with a filler filling rate of 30%-50%; S3 bacterial agent inoculation and biofilm formation: Inoculate the compound hydrolysis acidification bacterial agent into the hydrolysis acidification tank. The inoculation amount is 8%-12% of the effective volume of the tank. Carry out the biofilm formation culture for 7-10 days until the biofilm thickness on the packing surface reaches 1-2 mm. S4 Continuous Operation Treatment: The adjusted wastewater is introduced into the hydrolysis acidification tank in an upflow manner, with the hydraulic retention time controlled at 8-16 hours, the upflow velocity at 0.5-1.2 m / h, and the dissolved oxygen in the tank controlled below 0.2 mg / L to complete the hydrolysis acidification treatment.

2. The industrial wastewater hydrolysis acidification treatment process according to claim 1, characterized in that, The modified wear-resistant and impermeable composite filler comprises the following components by weight: 40-60 parts clay, 10-20 parts silicon carbide micro powder, 8-15 parts epoxy resin modified kaolin, 5-12 parts fly ash, 3-8 parts starch pore-forming agent, 1-3 parts silane coupling agent, and 15-25 parts deionized water.

3. The industrial wastewater hydrolysis acidification treatment process according to claim 2, characterized in that, The silicon carbide micro powder has a particle size of 200-400 mesh; the epoxy resin modified kaolin is prepared by drying kaolin at 120℃ for 2 hours, then adding epoxy resin E-44 at 5%-10% of the mass of kaolin, stirring at high speed to mix evenly, curing at 80℃ for 4 hours, and grinding through a 200-mesh sieve.

4. The industrial wastewater hydrolysis acidification treatment process according to claim 2, characterized in that, The preparation method of the modified wear-resistant and impermeable composite filler includes the following steps: W1. Weigh out clay, silicon carbide micro powder, epoxy resin modified kaolin, and fly ash by weight, add them to a ball mill and ball mill for 30-60 minutes to mix evenly and obtain a mixed powder. W2. Add starch pore-forming agent, silane coupling agent and deionized water to the mixed powder, and continue stirring for 20-30 minutes to obtain plastic clay. W3. The mud material is extruded into spherical particles with a diameter of 8-12 mm by a granulator and then air-dried at room temperature for 24 hours; W4. Place the air-dried granules into a muffle furnace, heat them to 1050-1150℃ at a rate of 3-5℃ / min, hold for sintering for 2-3 hours, and cool naturally to room temperature to obtain the filler matrix. W5. Immerse the filler matrix in a 5% (w / w) silane coupling agent ethanol solution for 2 hours, then remove it and dry it at 105°C for 1 hour to obtain the modified wear-resistant and impermeable composite filler.

5. The industrial wastewater hydrolysis acidification treatment process according to claim 1, characterized in that, The compound hydrolyzing acidifying bacterial agent, by volume, comprises: 20-30 parts of Clostridium butyricum fermentation broth, 15-25 parts of Vibrio acetophilia desulfurizing broth, 15-20 parts of hydrogen-producing and acetic acid-producing bacterial broth, 10-20 parts of Lactobacillus spp. , and 5-12 parts of white-rot fungal broth, with each broth having a concentration of 1.0 × 10⁻⁶. 8 -1.0×10 9 CFU / mL.

6. The industrial wastewater hydrolysis acidification treatment process according to claim 5, characterized in that, The preparation method of the compound hydrolyzed acidifying bacterial agent is as follows: after mixing the individual bacterial solutions in proportion, add a nutrient protectant with a mass of 2%-5% of the total mass of the mixed bacterial solution, and activate and culture at 25℃ for 24 hours to obtain the compound hydrolyzed acidifying bacterial agent. The nutritional protectant comprises, by weight, 10 parts glucose, 5 parts peptone, 2 parts potassium dihydrogen phosphate, and 0.5 parts magnesium sulfate.

7. The industrial wastewater hydrolysis acidification treatment process according to claim 1, characterized in that, The impermeable and wear-resistant lining is made of the following components by weight: 0-45 parts epoxy resin E-513, 10-18 parts curing agent polyamide 650, 5-10 parts silicon carbide whiskers, 8-15 parts mica powder, 0.3-0.8 parts defoamer, and 3-8 parts diluent acetone.

8. The industrial wastewater hydrolysis acidification treatment process according to claim 7, characterized in that, The construction method of the seepage-proof and wear-resistant lining is as follows: First, grind the inner wall of the pool to make it smooth and clean, apply the primer, then mix and stir the components of the seepage-proof and wear-resistant lining evenly, and apply it to the inner wall of the pool in 2-3 coats, with a total thickness of 1.5-2.5mm. It can be used after curing at room temperature for 72 hours.

9. The industrial wastewater hydrolysis acidification treatment process according to claim 1, characterized in that, In step S1, the pretreatment also includes adding polyaluminum chloride with a mass concentration of 50-100 mg / L to the equalization tank, stirring and reacting for 15 min, and then settling for 30 min to remove some suspended solids and colloidal substances.

10. The industrial wastewater hydrolysis acidification treatment process according to claim 1, characterized in that, In step S4, during the operation of the hydrolysis acidification tank, sludge is returned every 15 days, with a return ratio of 10%-20%. The returned sludge comes from the remaining sludge in the subsequent secondary sedimentation tank.

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