Photo-biochemical treatment method for caprolactone plant production wastewater

Abstract

The application discloses a photo-biochemical treatment method for caprolactone device production wastewater, which comprises three-stage combined process for treating the liquid extracted from the tower kettle of a stripping tower: S1 is peroxo acid reduction pretreatment-alkali neutralization pretreatment; S2 comprises a hydrolysis acidification treatment process, a sludge body anaerobic treatment process with a core-shell structure which is different from the existing granular sludge process, and an aerobic biological treatment process; and S3 is a combined process of a sedimentation tank and a biological filter tank. The combined process of peroxo acid reduction pretreatment-alkali neutralization pretreatment-hydrolysis acidification-biochemical anaerobic treatment-anoxic / aerobic biological treatment-sedimentation sludge recovery-biological membrane filtration is used for treating most of COD of the liquid extracted from the tower kettle of a caprolactone device, and the short board of the domestic lack of suitable matching caprolactone device wastewater treatment process is made up.

Description

Technical Field

[0001] This invention belongs to the field of organic wastewater treatment technology. Specifically, it relates to a stripping-pretreatment-modification method for wastewater from a caprolactone production unit. 2 O Biochemical treatment - post-treatment process. Background Technology

[0002] Because the production technology of ε-caprolactone monomer is currently monopolized by a few foreign companies, Hunan Juren New Material Co., Ltd. is the first domestic enterprise to achieve industrial-scale production of ε-caprolactone monomer with a capacity of 10,000 tons. Currently, there is a lack of suitable wastewater treatment processes to support caprolactone production in China. With the development of caprolactone production technology, a suitable treatment process for caprolactone wastewater is needed. Industrial wastewater typically contains a large number of pollutants. Effective treatment and reuse of industrial wastewater based on green wastewater treatment processes helps protect the environment and save energy, significantly reducing negative environmental impacts. This can bring significant economic and technological benefits to enterprises and society, and is a key path to achieving sustainable development.

[0003] The wastewater from the caprolactone unit is characterized by high concentration, good biodegradability, and fluctuations within the anaerobic system. Its main components include carboxylic acid esters (such as ethyl acetate and ethyl propionate), carboxylic acids (such as acetic acid, propionic acid, and small amounts of peroxyacids), and organic matter. High-load influent operation easily leads to acidification within the unit, significantly increasing the difficulty of operating the biological system.

[0004] Biochemical treatment methods mainly include aerobic activated sludge processes, biofilm processes, and anaerobic biological treatment technologies. However, microorganisms typically require harsh conditions, and their tolerance to environmental changes is limited. The anaerobic process section consumes the most COD, but traditional anaerobic processes for treating caprolactone industrial wastewater often result in sludge loss, making stable operation difficult. However, by improving and optimizing process conditions, enhancing the microbial environment, increasing microbial community stability, modifying existing anaerobic towers with microbial affinity packing materials, and extending the anaerobic sludge retention time, the problem of difficulty in increasing the influent load of caprolactone plants can be solved. Furthermore, using biochemical methods can better improve energy utilization. Summary of the Invention

[0005] To address the aforementioned problems, this invention discloses a photochemical treatment method for wastewater from caprolactone production.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A photochemical treatment method for wastewater from a caprolactone production unit includes the following steps:

[0008] S1. The bottom liquid of the stripping tower of caprolactone enters the regulating tank 1 for COD concentration monitoring and regulation. It is diluted with water to the preset concentration range, and then enters the oxidation tank and neutralization tank for pretreatment. Nutrients are added to obtain pretreated wastewater. The pretreatment includes peroxy acid reduction pretreatment and alkali neutralization pretreatment.

[0009] S2. After pretreatment, the wastewater is fed into the hydrolysis acidification tank for hydrolysis acidification, and then into the anaerobic tower for anaerobic biological treatment to obtain anaerobic effluent. The anaerobic effluent enters the equalization tank 2 for homogenization and equalization to obtain regulated wastewater. The regulated wastewater enters the anoxic and aerobic sections, and then enters the post-treatment stage of S3.

[0010] S3. After the anaerobic tower biochemical treatment, the wastewater is partially recycled back into the anaerobic tower as sludge. After the aerobic section is completed, the wastewater enters the sedimentation tank and biological filter before entering the discharge tank. It is discharged after passing the test.

[0011] A further improvement is that the peroxyacid reduction pretreatment involves reacting ferrous salt with the peroxyacid in the bottom product of the stripping tower of caprolactone, thereby reducing the peroxyacid concentration to less than 100 mg / L; the alkali neutralization pretreatment involves neutralizing the acidic substances using industrial caustic soda flakes until the pH of the pretreated wastewater is within the alkaline range.

[0012] A further improvement is that the pH of the pretreated wastewater is in the alkaline range, specifically 7.5 to 10.0.

[0013] Further improvements include the inclusion of nitrogen-containing salts, phosphorus-containing salts, other macronutrients, and micronutrients.

[0014] Nitrogen-containing salts are selected from one or more of nitrates, ammonium salts, nitrites, and urea;

[0015] Phosphorus salts are selected from one or more of dihydrogen phosphate, dihydrogen phosphate, and phosphate;

[0016] Other macronutrients are selected from one or more of potassium chloride, sodium sulfide, and magnesium sulfate.

[0017] The trace element nutrients are selected from one or more of the following: aluminum chloride, calcium chloride, zinc chloride, ferrous chloride, cobalt chloride, manganese chloride, nickel chloride, potassium iodide, manganese sulfate, ferrous sulfate, EDTA, sodium selenite, sodium tungstate, sodium molybdate, and boric acid.

[0018] Further improvements include an anaerobic tower body 3 comprising a bottom water distribution area, a middle packing area, and a top area; the bottom water distribution area is equipped with a water distribution pipe N1, a tangential liquid inlet N2, a tangential liquid inlet N3, and a thermometer inlet N4; the packing area is equipped with a packing loading and unloading pipe N5a, a packing loading and unloading pipe N5b, a pH meter inlet N9, and a first circular perforated sieve plate support 1 and a second circular perforated sieve plate support 7 fixed at the top and bottom respectively; the packing 2 is located above the first circular perforated sieve plate support 1 and distributed between the first circular perforated sieve plate support 1 and the second circular perforated sieve plate support 7; symmetrical transparent sight glasses 6 are provided in the middle and lower parts of the anaerobic tower body 3, a transparent material cylinder 8 is installed at the top, and a cover plate 5 is fixed at the top; a first circular perforated sieve plate support 6 is fixed above the transparent material cylinder 8. The second mesh screen support 7 has an overflow port N6 and a circulation return port N7 above it, and the cover plate 5 is connected to the biogas port N8; the anaerobic tower body 3 has a height-to-diameter ratio of 5:2 to 25:1, the top of the packing occupies 5% to 30% of the total volume of the anaerobic tower body, and the bottom water distribution area occupies 5% to 20% of the total volume; the transparent cylinder 8 is made of one or more composite materials of pressure-resistant glass and pressure-resistant transparent resin, and its volume occupies 5% to 50% of the packing area; the first mesh screen support 1 has three layers: the lower layer has an opening rate of 15% to 30% and a hole diameter of 8 to 12 mm, the middle layer has an opening rate of 30% to 50% and a hole diameter of 3 to 8 mm, and the upper layer has an opening rate of 50% to 95% and a hole diameter of 1 to 2 mm.

[0019] Further improvements, by mass percentage, include the following filler 2 comprising 60%–85% substrate and 15%–40% superabsorbent polymer (SAP); the substrate is one or more of the following materials: PP and / or PE, polycaprolactone, polycarbonate, polylactic acid, polyacrylate, or polymethacrylate; the substrate contains 0.1%–1% nano-metal powder; the SAP is selected from one or more of the following materials: fluff pulp, corn stalks, polyacrylate, starch, polyvinyl alcohol, and cellulose; the nano-metal powder includes one or more of the following materials: nano-zinc oxide, nano-manganese oxide, nano-iron powder, nano-iron oxide, nano-calcium oxide, and nano-magnesium oxide; the manufacturing method is as follows: after mixing the materials, they are added to a twin-screw mixer, with the feeding section temperature at 110–150℃, the melting section temperature at 110–160℃, the homogenization section temperature at 110–150℃, the screw speed at 150–500 rpm, and the density of filler 2 at 1.01–1.20 g / cm³. 3 Specific surface area is 1000~2000 m² 2 / m 3 The bulk density is 300~500 kg / m³ 3 .

[0020] Further improvements include an upward flow velocity of 0.1-20 m / h and a residence time of 1-5 days for the solution inside the anaerobic tower, with an influent volumetric loading rate of 0.5-30 kg COD. cr / m 3 •d, the temperature is controlled at 35-39℃, with daily temperature fluctuations not exceeding 2℃; the microbial community in the area corresponding to the light source includes photosynthetic bacteria of the Rhodospirilluce family; the photosynthetic bacteria of the Rhodospirilluce family include one or more of the following: Rhodopseudomonas palustris, Rhodospirillum capsulatum, and Rhodospirillum rubrum.

[0021] Further improvements include the anaerobic effluent flowing from the overflow pipe N6 into the equalization tank, followed by wastewater that has undergone anoxic and aerobic treatment before entering the sedimentation tank. Suspended solids and some sludge in the wastewater treated in the aerobic tank are separated into solids and water in the sedimentation tank. The remaining sludge is then concentrated and subjected to sludge dewatering plate and frame filter press treatment before the wastewater enters the biological filter. The biological filter removes residual organic matter and intercepts some microorganisms in the water. Finally, the wastewater is discharged after all pollution indicators are tested and found to meet the standards.

[0022] Aerobic treatment systems can adopt operating modes such as BAF and MBR.

[0023] Advantages of this invention:

[0024] 1. This invention utilizes a combined process to treat most of the COD in the bottom product of the stripping tower of a caprolactone unit, which includes peroxyacid reduction pretreatment, alkali neutralization pretreatment, hydrolysis acidification, biochemical anaerobic treatment, anoxic / aerobic biological treatment, sludge recovery, and biofilm filtration. This process fills the gap in domestic wastewater treatment technology for caprolactone units, which lacks suitable supporting processes.

[0025] 2. This invention optimizes the survival environment of microorganisms and enhances the stability of the microbial community by adjusting the upward flow velocity, adjusting the nutrient composition, setting a transparent material cylinder, and preparing modified packing material. It also constructs a two-stage anaerobic biochemical treatment zone with light and non-light conditions. The light-lit zone enriches photosynthetic bacteria of the Rhodospirillumaceae family, while the non-light-lit zone cultivates archaea microbial communities such as anaerobic bacilli and anaerobic methanogens. This solves the treatment problems of low anaerobic sludge retention rate and difficulty in increasing the sludge load of the process unit in the wastewater from the caprolactone unit. The effluent meets the national "Integrated Industrial Wastewater Discharge Standard".

[0026] 3. The improved anaerobic tower can use an upward flow rate several times that of the traditional one, resulting in a significant increase in removal rate and buffering capacity.

[0027] 4. The process involves a green biochemical system that removes peroxides from wastewater and converts COD in wastewater into methane, with a removal rate of over 90%. This brings significant economic and technological benefits and is a key path to achieving sustainable development. Attached Figure Description

[0028] Figure 1 This is a simplified process flow diagram.

[0029] Figure 2 This is a schematic diagram of the structure of an anaerobic tower implemented in this invention.

[0030] Figure 3 This is a comparison chart of species abundance enrichment in the examples and comparative examples. In the chart, data group E represents the example, and C represents the comparative example. Before sampling, all sampling equipment was disinfected. At least three replicate water samples were taken from each of the two anaerobic biological treatment zones: one under light (P1) and one without light (P2). After storage at low temperature, the samples were transferred to a -80°C freezer. The 16rDNA test results were then subjected to cluster analysis as shown below. Figure 3 The results shown verify that existing processes can be adjusted to enrich photosynthetic bacteria of the Rhodospirillumaceae family in the illuminated area and cultivate archaea microbial populations such as anaerobic bacilli and anaerobic methanogens in the non-illuminated area.

[0031] Figure 4 The presence of Vorticella, Isochrysis, Solitaria, and Scutellaria species in the aerobic process indicates that the aerobic tank has a good treatment effect.

[0032] Figure 5 The image shows the anaerobic flocs attached to the packing material. The bacterial flocs are tightly packed with clear boundaries, and the interstitial water is clear, indicating that the anaerobic tower has an excellent treatment effect. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0034] Example 1

[0035] According to the process diagram Figure 1 The treatment method for wastewater from caprolactone production mainly includes a three-stage combined process for the stripping tower bottom product: S1 is peroxyacid reduction pretreatment-alkali neutralization pretreatment; S2 is hydrolysis acidification-A 2 O is biological treatment; S3 is a combined process of sedimentation tank and biological filter.

[0036] Pretreatment stage S1 includes COD control of the stripper bottoms liquid in equalization tank one, and the reaction of residual peroxyacid with ferrous sulfate in the oxidation tank to reduce the peroxyacid and neutralize the acidic substances, monitoring its concentration to decrease to less than 100 mg / L. Industrial caustic soda is then used to neutralize the acidic substances to pH 8.5, providing a suitable environment for the subsequent hydrolysis-acidification-anaerobic system bacteria and improving its treatment efficiency.

[0037] Nutrients are added during process S1. The following is a nutrient solution composition: urea 300 mg / L, sodium dihydrogen phosphate 50 mg / L, potassium chloride 200 mg / L, ferrous sulfate 40 mg / L, manganese chloride tetrahydrate 4.5 mg / L, calcium chloride 20 mg / L, nickel chloride 0.5 mg / L, cobalt chloride 10 mg / L, EDTA 1 mg / L, sodium selenite 0.1 mg / L, and boric acid 0.5 mg / L.

[0038] S2: After the water from the pretreatment stage S1 has undergone nutrient salt, neutralization, and peroxide removal, it enters the hydrolysis acidification tank. The water sample stays in the hydrolysis acidification tank for 1 day. The water from the hydrolysis acidification tank enters the anaerobic tower, passes through the equalization tank, and then enters the anoxic tank and the aerobic tank. The aerobic tank is aerated using a Roots blower.

[0039] During the acclimatization period of the anaerobic tower, the process parameters were adjusted to 0.1 m³ / h, and the influent load was controlled at 1.0 kg COD. cr / m 3 ·d and below.

[0040] During the non-acclimation period, the process parameters of the anaerobic tower are adjusted to an upflow velocity of 8 m / h and the influent volumetric loading is controlled at 12 kg COD. cr / m 3 •d. The stay should be limited to 3 days.

[0041] In order to enhance the biological system for cultivating efficient bacterial communities in the S2 anaerobic tower, the packing material prepared by the process of Test Example 1, which is the preferred test example, is added to the anaerobic tower. When working, the light source of the anaerobic tower is turned on, and the wastewater enters the water distribution pipe from the bottom of the tower. The water distribution pipe uses a one-pipe-multi-point, ring-shaped continuous water distribution.

[0042] The post-treatment stage S3 includes a combined process of sedimentation tank and biological filter. The sedimentation tank is divided into an anaerobic sludge return process and a secondary sedimentation tank corresponding to aerobic biological treatment. Anaerobic effluent flows out through an overflow pipe; the suspended solids pass through the sedimentation tank for sludge-water separation, and part of the sludge is returned to the anaerobic tower. Wastewater enters the aerobic (AO) stage. After aerobic treatment, the wastewater enters the secondary sedimentation tank, where suspended solids and some sludge undergo sludge-water separation. The remaining sludge is concentrated and dewatered before the wastewater enters the biological filter. The biological filter removes some microorganisms from the water, and after testing, all pollution indicators of the wastewater meet standards before final discharge.

[0043] Example 2

[0044] Compared to Example 1, the nutrient composition was changed by adding nutrient mother liquor in process S1. The following is a nutrient solution composition: ammonium chloride 500 mg / L, diammonium hydrogen phosphate 100 mg / L, sodium sulfide 400 mg / L, calcium chloride 50 mg / L, aluminum chloride 0.5 mg / L, zinc chloride 0.5 mg / L, ferrous chloride 40 mg / L, manganese sulfate 4.5 mg / L, sodium tungstate 0.5 mg / L, sodium molybdate 0.5 mg / L, cobalt chloride 10 mg / L, EDTA 1 mg / L, sodium selenite 0.1 mg / L, and boric acid 0.5 mg / L.

[0045] Example 3

[0046] Compared to Example 2, the pretreatment stage S1 was adjusted to use industrial caustic soda flakes to neutralize acidic substances to pH=10.0, providing a suitable environment for the subsequent hydrolysis acidification-anaerobic system bacteria and improving their treatment efficiency.

[0047] The anaerobic digester operating parameters were adjusted to an upflow velocity of 20 m / h, a residence time of 5 days, and an influent volumetric loading of 30 kg COD. cr / m 3 ·d.

[0048] Example 4

[0049] Compared to Example 1, the pretreatment stage S1 was adjusted to use industrial caustic soda flakes to neutralize acidic substances to pH 7.5, providing a suitable environment for the subsequent hydrolysis acidification-anaerobic system bacteria and improving their treatment efficiency.

[0050] The anaerobic digester's operating parameters were adjusted to an upward flow velocity of 0.1 m / h, a residence time of 1 day, and an influent volumetric loading rate of 2.0 kg COD. cr / m 3 ·d.

[0051] Compared to Example 1, the nutrient composition was changed. Nutrients were added during process S1, and the following is a nutrient solution composition: sodium nitrate 300 mg / L, sodium nitrite 100 mg / L, sodium phosphate 80 mg / L, potassium chloride 200 mg / L, ferrous sulfate 40 mg / L, manganese sulfate 4.5 mg / L, calcium chloride 20 mg / L, nickel chloride 0.5 mg / L, cobalt chloride 10 mg / L, EDTA 1 mg / L, sodium selenite 0.1 mg / L, boric acid 0.5 mg / L, sodium tungstate 0.5 mg / L, and sodium molybdate 0.5 mg / L.

[0052] Comparative Example 1

[0053] The other conditions are the same as in Example 1, except that the light-transmitting area is shielded.

[0054] Comparative Example 2

[0055] Other conditions are the same as those in Comparative Example 1, except that the filler from Test Example 1 is not added, i.e., the conventional UASB process is used.

[0056] The test data for the process sections of the examples and comparative examples are as follows:

[0057]

[0058] Results analysis:

[0059] Based on process data and appendix Figure 3 Comparative analysis showed that Examples 2 and 1 differed only in nutrients. While the bacterial communities cultivated in both examples showed slight differences, the overall bacterial community differences were minimal, with anaerobic removal rates exceeding 90% and pH remaining stable. Example 3 adjusted some process conditions. At high upflow velocities, the relative abundance of acid-producing bacteria increased to some extent, while anaerobic bacteria and photosynthetic bacteria (Rhodospirillumaceae) decreased to some extent. However, the sampling points in the two different areas still showed differences in bacterial enrichment. Macroscopically, the process results showed a decrease in pH and a slight decrease in COD removal rate, mainly due to the increased influent flow leading to the growth of acid-producing bacteria. In Example 4, after adjusting the process conditions, the relative abundance of photosynthetic bacteria (Rhodospirillumaceae) and methanogens decreased to some extent. This was mainly due to a decrease in the influent flow leading to a reduction in the supply of carbonaceous organic matter. Macroscopically, the process indicators showed an increase in anaerobic removal rate and a better final effluent quality. However, Examples 1-4 can all be adjusted using existing processes to enrich photosynthetic bacteria of the Rhodospirillumaceae family in the illuminated area and cultivate archaea microbial populations such as anaerobic bacilli and anaerobic methanogens in the non-illuminated area.

[0060] In contrast, the sampling points in control groups 1 and 2 showed little difference, with no accumulation of bacterial flora. In Comparative Example 1, after removing light, the abundance of photosynthetic bacteria in the Rhodospirillumaceae family decreased significantly, while the abundance of anaerobic bacteria remained at a certain level, resulting in a removal rate of less than 85%. Comparative Example 2 was conducted under shaded conditions without the packing material from Test Example 1, using the traditional UASB process. Under these conditions, the abundance of photosynthetic bacteria and anaerobic bacteria in the Rhodospirillumaceae family was significantly inhibited, while the abundance of acid-producing bacteria increased significantly, ultimately leading to an acidic system and a significant decrease in the removal rate. Comparing the Example 1 and Comparative Example 2 demonstrates that the improved packing material has a particularly promoting effect on bacteria.

[0061] The packing material formulation was adjusted to test its biofilm formation. The following are the packing material preparation and testing results.

[0062] Test Example 1:

[0063] The modified filler uses 45% PE, 15% PP, 5% polycaprolactone, and 7% polycarbonate as the base material; 15% fluff pulp, 5% corn stalk, 6% polyvinyl alcohol, and 2% sodium polyacrylate as the effective water-absorbing components; 0.2% nano-metallic iron and 0.5% nano-calcium oxide are added. Based on the melt extrusion process, a sponge-like porous gel surface with extremely strong water absorption is constructed. The feeding section temperature is 110℃, the melting section temperature is 140℃, the homogenization section temperature is 130℃, and the screw speed is 300 rpm.

[0064] After process adjustments, the density is approximately 1.06 g / cm³. 3 Specific surface area is approximately 1600 m² 2 / m 3 Bulk density is approximately 370 kg / m³ 3 After anaerobic bacteria attached to the substrate, the dried packing material gained approximately 17% weight.

[0065] Test Example 2:

[0066] The modified filler uses 10% PE, 40% PP, 3% polylactic acid, 5% ethyl polyacrylate, and 2% polycarbonate as the base material; 10% starch, 5% sodium polyacrylate, and 25% polyvinyl alcohol are used as the effective water-absorbing components; 0.5% nano-metallic iron oxide and 0.5% nano-manganese oxide are added; the feeding section temperature is 110℃, the melting section temperature is 130℃, the homogenization section temperature is 130℃, and the screw speed is 500 rpm.

[0067] After process adjustments, the density is approximately 1.01 g / cm³. 3 Specific surface area is approximately 2000 m² 2 / m 3 Bulk density is approximately 300 kg / m³ 3 After anaerobic bacteria attach to the substrate, the dried packing material gains approximately 13% in weight.

[0068] Test Example 3:

[0069] The modified filler uses 45% PE, 5% PP, 18% polycaprolactone, 5% polylactic acid, 10% polycarbonate, and 7% polymethyl methacrylate as the base material; 10% starch and 5% sodium polyacrylate are used as the effective water-absorbing components; 0.1% nano magnesium oxide is added; the feeding section temperature is 110℃, the melting section temperature is 120℃, the homogenization section temperature is 150℃, and the screw speed is 400 rpm.

[0070] After process adjustments, the density is approximately 1.20 g / cm³. 3 Specific surface area is approximately 1160 m² 2 / m 3 Bulk density approximately 500 kg / m³ 3 After anaerobic bacteria attach to the substrate, the dried packing material gains approximately 14% in weight.

[0071] Test Example 4:

[0072] The modified filler uses 20% PE, 25% PP, 10% polycarbonate, 10% polymethyl methacrylate, and 10% polymethyl methacrylate as the base material; 15% cellulose, 5% sodium polyacrylate, and 5% polyvinyl alcohol are used as the effective water-absorbing components; 0.3% nano zinc oxide, 0.3% nano iron oxide, and 0.3% nano iron oxide are added; the feeding section temperature is 150℃, the melting section temperature is 160℃, the homogenization section temperature is 150℃, and the screw speed is 150 rpm. After process adjustment, the density is approximately 1.11 g / cm³. 3 Specific surface area is approximately 1350 m² 2 / m 3 Bulk density is approximately 415 kg / m³ 3 After anaerobic bacteria attach to the substrate, the dried packing material gains approximately 13% in weight.

[0073] Test Example 5:

[0074] The modified filler uses 50% PP, 12% polycarbonate, 5% ethyl polyacrylate, and 8% polycaprolactone as the base material; 5% cellulose, 15% sodium polyacrylate, and 5% polyvinyl alcohol are used as the effective water-absorbing components; 0.7% nano-calcium oxide and 0.2% nano-manganese oxide are added; the feeding section temperature is 110℃, the melting section temperature is 110℃, the homogenization section temperature is 120℃, and the screw speed is 250 rpm. After process adjustment, the density is approximately 1.15 g / cm³. 3 Specific surface area is approximately 1000 m² 2 / m 3 Bulk density is approximately 440 kg / m³ 3 After anaerobic bacteria attached to the substrate, the dried packing material gained approximately 11% weight.

[0075] Comparative Test Case 1

[0076] Anaerobic bacterial biofilm formation tests were conducted using commercially available polyamide and polyolefin packing materials. After biofilm formation, the packing materials were dried, and the weight gain was measured.

[0077] Its specifications are as follows:

[0078]

[0079] After drying, the polyamide packing material showed a weight gain of approximately 6% after anaerobic bacterial colonization, while the polyolefin packing material showed a weight gain of approximately 5%. The packing material prepared using the test examples exhibited a higher retention rate of anaerobic bacteria than commercially available packing materials in China.

[0080] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. Other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and shown herein.

Claims

1. A method for photo-biochemical treatment of caprolactone plant production wastewater, characterized by, It comprises the following steps: S1, the capillary tower of caprolactone is taken out from the adjusting pool one to monitor and adjust the COD concentration, and water is diluted to the preset concentration range, and then enters the oxidation tank and the neutralization pool for pretreatment, and then the nutrient salt is added to obtain the pretreated wastewater, the pretreatment comprises peroxo acid reduction pretreatment and alkali neutralization pretreatment; S2, the pretreated wastewater is input into the hydrolysis acidification tank for hydrolysis acidification, and then enters the anaerobic tower for anaerobic biological treatment to obtain anaerobic effluent, and the anaerobic effluent enters the adjusting pool two, and is homogenized and quantified to obtain the adjusted wastewater; the adjusted wastewater enters the anoxic and aerobic sections, and then enters the post-treatment stage of S3; The anaerobic tower cylinder (3) comprises a bottom water distribution area, a middle filler area and a top area; the bottom water distribution area is provided with a water distribution pipe (N1), a tangent liquid inlet two (N2), a tangent liquid inlet (N3) and a thermometer pipe (N4); the filler area is provided with a filler loading and unloading pipe one (N5a), a filler loading and unloading pipe two (N5b), a pH meter pipe (N9), an upper and lower circular first mesh sieve plate support (1) and a second mesh sieve plate support (7) respectively fixed; wherein the first mesh sieve plate support (1) is provided with a filler (2) above, and the filler (2) is distributed between the first mesh sieve plate support (1) and the second mesh sieve plate support (7); the anaerobic tower cylinder (3) is provided with symmetric transparent sight glasses (6) in the middle and lower parts, and is provided with a transparent material cylinder (8) at the upper part, and is provided with a cover plate (5) at the top; the transparent material cylinder (8) is fixed with the second mesh sieve plate support (7) above, and is provided with an overflow pipe (N6) and a circulating backflow pipe (N7) above the second mesh sieve plate support (7), and the cover plate (5) is communicated with a biogas pipe (N8); the height-diameter ratio of the anaerobic tower cylinder (3) is 5:2~25:1, the top filler occupies 5%~30% of the total volume of the anaerobic tower cylinder, and the bottom water distribution area occupies 5%~20% of the total volume; the transparent material cylinder (8) is made of one or several composite materials of pressure-resistant glass, pressure-resistant transparent resin material, and the volume range occupies 5%~50% of the filler area; the first mesh sieve plate support (1) has three layers of upper, middle and lower layers, the lower layer has an opening rate of 15%~30%, a pore size of 8~12mm, the middle layer has an opening rate of 30%~50%, a pore size of 3~8mm, and the upper layer has an opening rate of 50%~95%, a pore size of 1~2mm; When working, the anaerobic tower light source is turned on, and the bacterial flora in the corresponding area of the anaerobic tower light source comprises Rhodospirillaceae photosynthetic bacteria; the Rhodospirillaceae photosynthetic bacteria comprises one or several of Rhodopseudomonas palustris bacteria, Rhodobacter capsulatus bacteria and Rhodospirillum rubrum bacteria; S3, part of the anaerobic tower biochemical treated wastewater is returned to the anaerobic tower for sludge backflow; after the aerobic section treatment, it enters the sedimentation tank and the biological filter tank, and then enters the external discharge tank, and is discharged after detection.

2. The photo-biochemical treatment method of caprolactone plant production wastewater according to claim 1, characterized by, The peroxo acid reduction pretreatment is to react ferrous salt with peroxo acid in the capillary tower of caprolactone to reduce the concentration of peroxo acid to less than 100 mg / L; the alkali neutralization pretreatment is to use industrial flake alkali to neutralize the acid substance, and the pH of the pretreated wastewater is in the alkaline range.

3. The photo-biochemical treatment method of caprolactone plant production wastewater according to claim 2, characterized by, The pH of the pretreated wastewater is in an alkaline range, and is 7.5-10.

0.

4. The photo-biochemical treatment method of caprolactone plant production wastewater according to claim 1, characterized by, The nutrient salt comprises nitrogen-containing salt, phosphorus-containing salt, other macro-nutrient salt and trace element nutrient salt; The nitrogen-containing salt is selected from one or more of nitrate, ammonium salt, nitrite and urea; The phosphorus-containing salt is selected from one or more of dihydrogen phosphate, hydrogen phosphate and phosphate; The other macro-nutrient salt is selected from one or more of potassium chloride, sodium sulfide and magnesium sulfate; The trace element nutrient salt is selected from one or more of aluminum chloride, calcium chloride, zinc chloride, ferrous chloride, cobalt chloride, manganese chloride, nickel chloride, potassium iodide, manganese sulfate, ferrous sulfate, EDTA, sodium selenite, sodium tungstate, sodium molybdate and boric acid.

5. The photo-biochemical treatment method of caprolactone plant production wastewater according to claim 1, characterized by, The filler (2) comprises 60-85% of a base material by mass percentage, 15-40% of a high molecular water-absorbing resin; the base material is one or several materials selected from PP and / or PE, polycaprolactone, polycarbonate, polylactic acid, polyacrylate or polymethacrylate; 0.1-1% of nano metal powder is added to the base material; the high molecular water-absorbing resin is selected from one or several materials selected from fluff pulp, corn straw, polyacrylate, starch, polyvinyl alcohol and cellulose; the nano metal powder comprises one or several materials selected from nano zinc oxide, nano manganese oxide, nano iron powder, nano iron oxide, nano calcium oxide and nano magnesium oxide; the manufacturing method is as follows: after the materials are mixed, a double-screw mixing machine is used, the temperature of a feeding section is 110-150 DEG C, the temperature of a melting section is 110-160 DEG C, the temperature of a homogenizing section is 110-150 DEG C, the screw rotation speed is 150-500 rpm, the density of the filler (2) is 1.01-1.20 g / cm 3 , the specific surface area is 1000-2000 m 2 / m 3 , and the bulk density is 300-500 kg / m 3 .

6. The photo-biochemical treatment method of caprolactone plant production wastewater according to claim 1, characterized by, The ascending flow rate of the solution in the anaerobic tower is 0.1-20 m / h, the residence time is 1-5 days, and the water volume load is 0.5-30 kg COD cr / m 3 d, the temperature is controlled at 35-39℃, and the daily temperature fluctuation is not greater than 2℃.

7. The photo-biochemical treatment method of caprolactone plant production wastewater according to claim 1, characterized by, The anaerobic effluent flows out from the overflow pipe (N6) into the adjusting tank, and then the wastewater treated by the anaerobic and aerobic processes enters the sedimentation tank. The suspended solids and part of the sludge in the wastewater treated by the aerobic process are separated from the water in the sedimentation tank. The remaining sludge is concentrated and then subjected to the plate-and-frame filter pressing process for sludge dewatering. The wastewater enters the biological filter. The biological filter removes the remaining organic matter in the water body and intercepts part of the microorganisms. Finally, the wastewater is detected for compliance with various pollution indicators.

Images