A treatment system and method for high-concentration hemicellulose deep processing wastewater

Abstract

The present invention relates to a treatment system and method for high-concentration hemicellulose deep processing wastewater, and belongs to the field of viscose fiber production wastewater. The system includes a blending tank, a collection tank, an aerobic tank, an aeration tank, a first sedimentation tank, a delayed aeration tank and a second sedimentation tank that are connected in sequence. Through this system, the high-concentration hemicellulose deep processing wastewater is collected and the pH value is adjusted to 7.5-8.5, and then the wastewater inflow is gradually increased, the hydraulic retention time is shortened, and a specific bacterial strain that can treat the wastewater is domesticated and cultured for treatment. The present invention domesticates a specific biological strain suitable for treating high-concentration hemicellulose deep processing wastewater, and utilizes a biological method to efficiently and stably degrade the COD in the wastewater, so that the wastewater with high salinity and high COD can be discharged without dilution to meet the urban third-level emission standard.

Description

Technical Field

[0001] The invention relates to a treatment system and a treatment method for high-concentration hemicellulose deep-processing wastewater, and belongs to the field of viscose fiber production wastewater, in particular to the field of high-concentration hemicellulose deep-processing wastewater in the viscose fiber production process. Background Art

[0002] During the viscose fiber production process, the alkali liquor produced in the pressing process of the raw liquid workshop contains a large amount of hemicellulose. In order to recycle this part of the alkali liquor, the high-concentration hemicellulose contained can be deeply processed into functional sugars. The wastewater generated during the processing has undergone ion exchange and electrodialysis with cation-ion columns. The activated carbon used for decolorization in the wastewater has been collected by plate and frame filtration. The wastewater is high-salt and high-COD wastewater with a pH value between 1.5 and 2.5. Although B / C is greater than 0.3, the wastewater contains large-chain organic matter and has a complex composition. It is extremely difficult to degrade it using ordinary biological methods.

[0003] Currently, most domestic sugar companies use anaerobic reactors such as IC reactors or UASB reactors to perform anaerobic reactions on wastewater, and then combine aerobic processes and other advanced treatment processes to treat xylose wastewater. This wastewater contains a large amount of sulfate, which produces a large amount of H2S during the anaerobic process. This has a strong inhibitory effect on the subsequent production of methane, resulting in unstable anaerobic reactor operation and poor COD removal. Although the methane produced can be recycled for energy, it cannot be avoided that the methane is treated by igniting a torch during maintenance. Moreover, methane is a flammable substance and has strict requirements for safe treatment facilities. Therefore, the application scope of anaerobic reactors is relatively limited. Summary of the Invention

[0004] In order to address the deficiencies of the prior art, the present invention provides a system and method for treating high-concentration hemicellulose deep processing wastewater. The present invention is based on a specific biological strain suitable for treating high-concentration hemicellulose deep processing wastewater obtained through domestication, and utilizes a biological method to efficiently and stably degrade the COD in the wastewater, so that wastewater with high salinity and high COD can be discharged without dilution to meet the urban third-level emission standards. The system of the present invention has good stability and low operating costs. After normal operation, it can complete the treatment of high-concentration hemicellulose deep processing wastewater without increasing biomass. The present invention does not use an anaerobic reactor and does not produce flammable gas.

[0005] The technical solutions provided by the present invention are as follows:

[0006] A treatment system for high-concentration hemicellulose deep processing wastewater comprises a mixing tank, a collection tank, an aeration tank, an aeration tank, a primary sedimentation tank, a delayed aeration tank and a secondary sedimentation tank, which are sequentially connected.

[0007] The mixing tank is connected to the collection tank via a pump;

[0008] The collection tank is connected to the aerobic tank via a pump;

[0009] The aeration tank is provided with a submersible mixer and is connected to the aeration tank through a gravity flow pipe. A sludge internal reflux channel is provided inside the aeration tank. The sludge outlet of the aeration tank is connected to the sludge treatment process through a sludge pipe. The outlet of the aeration tank for discharging H2S gas is connected to the waste gas treatment process.

[0010] The aeration tank is connected to the settling tank via a gravity flow pipe;

[0011] The settling tank is connected to the delayed aeration tank through a gravity flow pipe;

[0012] The delayed aeration tank is connected to the secondary sedimentation tank through a gravity flow pipeline;

[0013] The sludge outlet at the bottom of the secondary sedimentation tank is connected to the delayed aeration tank through a return sludge pipeline, and is also connected to the sludge treatment process.

[0014] Specifically, the bottom sludge outlet of the settling tank is connected to the sludge treatment pipeline.

[0015] Specifically, a sludge return hole is provided at the bottom of the isolation wall of the aeration tank. Driven by the mixer, part of the sludge returns to the inlet of the aeration tank, achieving the effect of evenly distributing the sludge.

[0016] Specifically, the wastewater treated in the aerobic tank is the upper effluent, which can reduce the amount of sludge loss.

[0017] Specifically, the sludge in the aerobic tank is discharged to the sludge treatment process once every three days, which can reduce the toxicity of the sludge and ensure the sludge concentration.

[0018] The present invention also provides a method for treating high-concentration hemicellulose deep processing wastewater, which is treated using a high-concentration hemicellulose deep processing wastewater treatment system, comprising the following steps:

[0019] Step 1): On Day 1, perform the following steps:

[0020] 1a) injecting clean water into the blending tank, collection tank, first settling tank and aeration tank until the liquid level reaches the overflow outlet of the above structures;

[0021] Injecting activated sludge and clean water into the aerobic tank until the liquid level reaches the overflow port of the aerobic tank, adjusting the activated sludge concentration to 3000-5000 mg / L, and then adding high-concentration hemicellulose deep processing wastewater separately to adjust the COD concentration in the aerobic tank to 30-80 mg / L;

[0022] Inject activated sludge and clean water into the delayed aeration tank until the liquid level reaches the overflow port of the delayed aeration tank. Adjust the activated sludge concentration to 2500-3500 mg / L. Then add high-concentration hemicellulose deep processing wastewater separately. Control the COD concentration in the delayed aeration tank to 20-80 mg / L. Open the compressed air valve for aeration and control the dissolved oxygen to 2-4 mg / L.

[0023] 1b) Starting to inject high-concentration hemicellulose deep processing wastewater into the blending tank, and maintaining the pH in the blending tank at 7.5-8.5 for treatment.

[0024] Specifically, the COD value of the high-concentration hemicellulose deep processing wastewater is 5000-8000 mg / L.

[0025] Specifically, the pH value of the high-concentration hemicellulose deep processing wastewater is 1.5-2.5.

[0026] Specifically, the activated sludge in the facultative aerobic tanks is surplus activated sludge from a viscose fiber production plant and is inherently salt-tolerant. The facultative aerobic tanks are an oxygen-free environment. Through continuous acclimatization in this system, salt-tolerant facultative aerobic bacteria capable of reducing sulfate and decomposing COD in environments with little or no molecular oxygen are screened and enriched.

[0027] Specifically, the activated sludge in the delayed aeration tank comes from the residual activated sludge in the aerobic tank of a viscose fiber production enterprise. It is salt-tolerant. Through acclimation with a longer residence time, salt-tolerant aerobic bacteria that can adapt to the wastewater after treatment in the facultative aerobic tank are screened and enriched, and the residual broken chain small molecular organic matter is decomposed to achieve the effect of removing COD.

[0028] Specifically, the speed of the submersible mixer in the aerobic tank is 80-100 rpm, which ensures that the sludge circulates at the bottom of the aerobic tank, so as to ensure that the sludge does not accumulate and is effectively utilized, and does not mix too evenly with the wastewater to cause excessive loss of sludge in the aerobic tank.

[0029] Specifically, if the sludge produced in the aerobic tank enters the delayed aeration tank through the gas shock of the aeration tank, it will cause irreversible biological toxicity to the aerobic system. The main function of the sedimentation tank is to intercept this part of the sludge.

[0030] Specifically, the concentration of dissolved oxygen in the delayed aeration tank is 1.5-2.5 mg / L to ensure that there is a dissolved oxygen environment in the delayed aeration tank that is sufficient for the survival of microorganisms.

[0031] Specifically, the delayed aeration tank has a longer sewage retention time than a common aerobic tank and has better tolerance for sewage treated in an aerobic tank.

[0032] Based on the above technical solution:

[0033] Salt-tolerant facultative oxic bacteria can be domesticated in facultative oxic tanks. Salt-tolerant facultative oxic bacteria can reduce sulfate in an environment with no or little molecular oxygen, thereby reducing COD. Specifically, in facultative oxic tanks, large-chain organic matter can be decomposed into simple substances such as monosaccharides, amino acids, and fatty acids.

[0034] Salt-tolerant aerobic bacteria can be domesticated in delayed aeration tanks. Salt-tolerant aerobic bacteria can adapt to wastewater treated in facultative aerobic tanks and deeply decompose residual broken-chain organic matter.

[0035] Furthermore, the method for treating high-concentration hemicellulose deep processing wastewater further includes step 2): on the 2nd to 10th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the facultative aeration tank by a pump, and then flows into the aeration tank, the first sedimentation tank, the delayed aeration tank, and the second sedimentation tank in sequence by gravity flow, wherein the flow control meets the following conditions:

[0036] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank is 5-7 days;

[0037] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank is 11-13 days.

[0038] Based on the above technical solution, by the 10th day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 90.6%.

[0039] Furthermore, the method for treating high-concentration hemicellulose deep processing wastewater further includes step 3): on the 11th to 18th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank by a pump, and then flows into the aeration tank, the first sedimentation tank, the delayed aeration tank, and the second sedimentation tank in sequence by gravity flow, wherein the flow control meets the following conditions:

[0040] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank is 2-4 days;

[0041] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank is 5-7 days.

[0042] Based on the above technical solution, by the 18th day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 93.7%.

[0043] In the above technical solution, the setting of the residence time in step 2) and step 3) can provide sufficient time for the initial and growth stages of domestication, which is conducive to enriching more beneficial bacterial species.

[0044] Furthermore, the method for treating high-concentration hemicellulose deep processing wastewater further includes step 4): on the 19th to 21st day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank by a pump, and then flows into the aeration tank, the first sedimentation tank, the delayed aeration tank, and the second sedimentation tank in sequence by gravity flow, wherein the flow control meets the following conditions:

[0045] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank is 2-3 days;

[0046] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank is 4-6 days.

[0047] Based on the above technical solution, by the 21st day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 95.1%.

[0048] Furthermore, the method for treating high-concentration hemicellulose deep processing wastewater further includes step 5): on the 22nd to 24th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank by a pump, and then flows into the aeration tank, the first sedimentation tank, the delayed aeration tank, and the second sedimentation tank in sequence by gravity flow, wherein the flow control meets the following conditions:

[0049] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank is 1-2 days;

[0050] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank is 3-4 days.

[0051] Based on the above technical solution, by the 24th day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 94.7%.

[0052] Furthermore, the method for treating high-concentration hemicellulose deep processing wastewater further includes step 6): on the 25th to 27th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank by a pump, and then flows into the aeration tank, the first sedimentation tank, the delayed aeration tank, and the second sedimentation tank in sequence by gravity flow, wherein the flow control meets the following conditions:

[0053] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank is 1.0-1.4 days;

[0054] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank is 2.2-2.6 days.

[0055] Based on the above technical solution, by the 27th day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 94.7%.

[0056] Furthermore, the method for treating high-concentration hemicellulose deep processing wastewater further includes step 7): on the 28th to 31st day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the facultative aeration tank by a pump, and then flows into the aeration tank, the first sedimentation tank, the delayed aeration tank, and the second sedimentation tank in sequence by gravity flow, wherein the flow control meets the following conditions:

[0057] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank is 0.8-1.0 day;

[0058] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank is 1.7-1.9 days.

[0059] During the 28th to 31st day, the clean water initially added to each structure can be completely replaced by high-concentration hemicellulose deep processing wastewater.

[0060] Based on the above technical solution, by the 31st day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 94.8%.

[0061] Furthermore, the method for treating high-concentration hemicellulose deep processing wastewater further includes step 8): on days 32-35, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the facultative aeration tank by a pump, and then flows into the aeration tank, the first sedimentation tank, the delayed aeration tank, and the second sedimentation tank in sequence by gravity flow, wherein the flow control meets the following conditions:

[0062] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank is 0.7-0.9 days;

[0063] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank is 1.5-1.7 days.

[0064] Based on the above technical solution, by the 35th day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 95.1%.

[0065] Overall, after 35 days of acclimation, the COD removal rate of high-concentration hemicellulose deep processing wastewater can be maintained at 95.1%, and the effluent COD can be maintained below 500 mg / L.

[0066] Furthermore, starting from the 36th day, the removal rate can be stabilized at around 95% by treating the wastewater according to the flow parameters of the 35th day.

[0067] Based on the above technical solution, while ensuring the actual removal rate, the residence time of structures such as the aeration tank and the delayed aeration tank gradually decreases during the domestication process. After the domestication is completed, an extremely low residence time requirement is finally reached, thereby improving the treatment efficiency and reducing the pool capacity requirements.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] The present invention domesticates a specific bacterial strain suitable for high-concentration hemicellulose deep processing wastewater and applies it to the facultative aerobic and aerobic treatment of high-concentration hemicellulose deep processing wastewater. During the domestication process, the strain's tolerance to wastewater is gradually increased, and the sewage loading capacity is gradually enhanced. The domesticated bacterial strain is used in both facultative aerobic and aerobic environments to degrade organic matter in the wastewater, ultimately achieving discharge standards.

[0070] During operation, the present invention generates a small amount of mud during the neutralization process in the blending tank, eliminating the need for a flocculant flocculation process. The wastewater contains a certain amount of carbon and nitrogen sources, eliminating the need for the addition of nutrients. The process system has good stability, low operating costs, and a wide range of applications. After normal operation, the process can complete the treatment of high-concentration hemicellulose deep processing wastewater without increasing biomass.

[0071] The present invention does not use anaerobic reaction equipment and does not produce flammable gas;

[0072] Once the strain of the present invention is domesticated, the process will run stably and be simple to operate. Wastewater with high salinity and high COD can be discharged without dilution to meet the urban Class III emission standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 It is a process flow chart of the treatment system for high-concentration hemicellulose deep processing wastewater provided by the present invention.

[0074] Figure 2 This is an overhead view of the aeration pool.

[0075] Attachment Figure 1 、 2 The structures represented by each number are listed as follows:

[0076] 1. Mixing tank, 2. Collection tank, 3. Aeration tank, 31. Submersible mixer, 32. Isolation wall, 33. Wastewater inlet, 34. Wastewater outlet, 35. Sludge return hole, 4. Aeration tank, 5. Primary sedimentation tank, 6. Delayed aeration tank, 7. Secondary sedimentation tank. DETAILED DESCRIPTION

[0077] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0078] Example 1

[0079] like Figure 1 As shown, the treatment system for high-concentration hemicellulose deep processing wastewater includes a blending tank 1, a collection tank 2, an aeration tank 3, an aeration tank 4, a primary sedimentation tank 5, a delayed aeration tank 6 and a secondary sedimentation tank 7 which are connected in sequence.

[0080] Mixing tank 1 is connected to collection tank 2 via a centrifugal pump. Collection tank 2 is connected to facultative aeration tank 3 via a screw pump. Facultative aeration tank 3 is equipped with a submersible mixer and connected to aeration tank 4 via a gravity flow pipe. Aeration tank 4 is connected to primary sedimentation tank 5 via a gravity flow pipe. Primary sedimentation tank 5 is connected to delayed aeration tank 6 via a gravity flow pipe. Delayed aeration tank 6 is connected to secondary sedimentation tank 7 via a gravity flow pipe. High-concentration hemicellulose deep processing wastewater overflows from the facultative aeration tank into the secondary sedimentation tank under the action of gravity. Mixing tank 1 may also be equipped with a mixer.

[0081] Based on this technical solution, specific bacterial strains suitable for high-concentration hemicellulose deep processing wastewater can be domesticated in facultative aeration tanks and delayed aeration tanks, and high-concentration hemicellulose deep processing wastewater with high salinity and high COD can be treated efficiently and stably under high water inflow and short hydraulic retention time.

[0082] Example 2

[0083] On the basis of Example 1, Figure 1 As shown, the bottom sludge outlet of the primary settling tank 5 is connected to the sludge treatment pipeline. The bottom sludge outlet of the secondary settling tank 7 is connected to the delayed aeration tank 6 via a return sludge pipeline, which is also connected to the sludge treatment pipeline. Based on this technical solution, some of the excess sludge in the secondary settling tank can be reused, and some of the excess sludge in the primary and secondary settling tanks can be discharged.

[0084] Example 3

[0085] Based on the above embodiments, Figure 2 As shown, a flow channel formed by a partition wall 32 is provided within the aeration tank 3. A wastewater inlet 33 is located at the beginning of the flow channel, and a wastewater outlet 34 is located at the end of the flow channel. A sludge return hole 35 is provided at the bottom of the partition wall 32 near the wastewater inlet 33. The sludge return hole 35 connects to the flow channel and forms an internal sludge return channel. Submersible mixers 31 are installed between the partition wall 32 and various corners of the aeration tank 3.

[0086] The wastewater outlet 34 of the aeration tank 3 is connected to the gravity flow pipeline, the sludge outlet of the aeration tank 3 is connected to the sludge treatment process through the sludge pipeline, and the H2S gas discharge outlet of the aeration tank 3 is connected to the waste gas treatment process.

[0087] Example 4

[0088] A method for treating high-concentration hemicellulose deep processing wastewater, using a high-concentration hemicellulose deep processing wastewater treatment system, comprises the following steps:

[0089] Step 1): On Day 1, perform the following steps:

[0090] 1a) injecting clean water into the blending tank 1, the collecting tank 2, the settling tank 5 and the aeration tank 4 until the liquid level reaches the overflow outlet of the above structures;

[0091] Inject activated sludge and clean water into the aerobic tank 3 until the liquid level reaches the overflow port of the aerobic tank 3, adjust the activated sludge concentration in the tank to about 4000 mg / L, and then add high-concentration hemicellulose deep processing wastewater separately to adjust the COD concentration in the aerobic tank 3 to about 55 mg / L;

[0092] Inject activated sludge and clean water into the delayed aeration tank 6 until the liquid level reaches the overflow port of the delayed aeration tank 6. Adjust the activated sludge concentration to about 2750 mg / L. Then, add high-concentration hemicellulose deep processing wastewater separately. Control the COD concentration in the delayed aeration tank 6 to about 55 mg / L. Open the compressed air valve for aeration and control the dissolved oxygen to about 3 mg / L.

[0093] 1b) High-concentration hemicellulose deep processing wastewater is injected into the preparation tank 1, and the pH in the preparation tank 1 is maintained at 7.5-8.5 by adding 1 mol / L NaOH for treatment;

[0094] Step 2): On the 2nd to 10th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank 3, and then flows into the aeration tank 4, the first sedimentation tank 5, the delayed aeration tank 6 and the second sedimentation tank 7 in sequence by gravity flow, wherein the flow control meets the following conditions:

[0095] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank 3 is 6 days;

[0096] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank 6 is 12 days. On the 10th day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 90.6%;

[0097] Step 3): On the 11th to 18th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank 3, and then flows into the aeration tank 4, the first sedimentation tank 5, the delayed aeration tank 6 and the second sedimentation tank 7 in sequence by gravity flow, wherein the flow control meets the following conditions:

[0098] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank 3 is 3 days;

[0099] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank 6 is 6 days. On the 18th day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 93.7%;

[0100] Step 4): On days 19-21, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank 3 and then flows by gravity into the aeration tank 4, the first sedimentation tank 5, the delayed aeration tank 6 and the second sedimentation tank 7, wherein the flow control meets the following conditions:

[0101] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank 3 is 2.5 days;

[0102] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank 6 is 5 days. On the 21st day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 95.1%;

[0103] Step 5): On the 22nd to 24th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank 3, and then flows into the aeration tank 4, the first sedimentation tank 5, the delayed aeration tank 6 and the second sedimentation tank 7 in sequence by gravity flow, wherein the flow control meets the following conditions:

[0104] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank 3 is 1.5 days;

[0105] The residence time of high-concentration hemicellulose deep processing wastewater in the extended aeration tank 6 is 3.5 days. By the 24th day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 94.7%;

[0106] Step 6): On the 25th to 27th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank 3, and then flows into the aeration tank 4, the first sedimentation tank 5, the delayed aeration tank 6 and the second sedimentation tank 7 in sequence by gravity flow, wherein the flow control meets the following conditions:

[0107] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank 3 is 1.2 days;

[0108] The residence time of high-concentration hemicellulose deep processing wastewater in the extended aeration tank 6 is 2.4 days. By the 27th day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 94.7%;

[0109] Step 7): On days 28-31, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank 3 and then flows by gravity into the aeration tank 4, the first sedimentation tank 5, the delayed aeration tank 6 and the second sedimentation tank 7, wherein the flow control meets the following conditions:

[0110] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank 3 is 0.9 days;

[0111] The residence time of high-concentration hemicellulose deep processing wastewater in the extended aeration tank 6 is 1.8 days. By the 31st day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 94.8%;

[0112] Step 8): On days 32-35, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank 3 and then flows by gravity into the aeration tank 4, the first sedimentation tank 5, the delayed aeration tank 6 and the second sedimentation tank 7, wherein the flow control meets the following conditions:

[0113] The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank 3 is 0.8 days;

[0114] The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank 6 is 1.6 days. By the 35th day after the start of treatment, the actual COD removal rate of high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank can reach 95.1%.

[0115] The COD value of the influent of high-concentration hemicellulose deep processing wastewater is about 8000 mg / L.

[0116] The pH value of the influent of high-concentration hemicellulose deep processing wastewater is about 1.8.

[0117] The activated sludge in the facultative aerobic tank 3 comes from the residual activated sludge in the aerobic tank of the viscose fiber plant of the chemical fiber enterprise.

[0118] The activated sludge in the delayed aeration tank 6 comes from the excess activated sludge in the aerobic tank of the viscose fiber plant of the chemical fiber enterprise.

[0119] The rotation speed of the submerged mixer in the aeration tank 3 is 90 rpm.

[0120] The concentration of dissolved oxygen in the delayed aeration tank 6 is between 2.0 and 2.4 mg / L.

[0121] After 35 days of acclimation, the COD removal rate of high-concentration hemicellulose deep processing wastewater can be maintained at 95.1%, and the effluent COD can be maintained at about 390 mg / L.

[0122] Comparative Example 1

[0123] Referring to the steps of Example 4, the difference is that the activated sludge in the facultative aerobic tank 3 adopts the residual activated sludge from the aerobic tank of a certain milk processing plant; the activated sludge in the delayed aeration tank 6 adopts the residual activated sludge from the aerobic tank of a certain milk processing plant. The results are as follows:

[0124] By the 10th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 42.1%;

[0125] By the 18th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 45.9%;

[0126] On the 21st day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 48.0%;

[0127] By the 24th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 49.8%;

[0128] By the 27th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 50.3%;

[0129] By the 31st day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 52.7%;

[0130] By the 35th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 54.5%.

[0131] After 35 days of acclimation, the COD of the effluent from high-concentration hemicellulose deep processing wastewater was about 3640 mg / L.

[0132] Comparative Example 2

[0133] Refer to the steps of Example 4, except that the aeration tank 3 and its related steps are removed, that is, the wastewater from the collection tank 2 is directly fed into the aeration tank 4. The results are as follows:

[0134] By the 10th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 43.3%;

[0135] By the 18th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 48.5%;

[0136] On the 21st day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 42.7%;

[0137] By the 24th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 36.6%;

[0138] By the 27th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 30.1%;

[0139] By the 31st day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 23.3%;

[0140] By the 35th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 22.1%.

[0141] After 35 days of acclimation, the COD of the effluent from high-concentration hemicellulose deep processing wastewater was about 6230 mg / L.

[0142] Comparative Example 3

[0143] Referring to the steps of Example 4, the difference is that the aeration tank 4 and its related steps are removed, that is, the wastewater from the aeration tank 3 directly enters the settling tank 5. The results are as follows:

[0144] By the 10th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 65.4%;

[0145] By the 18th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 68.8%;

[0146] On the 21st day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 70.1%;

[0147] By the 24th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 72.4%;

[0148] By the 27th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 77.5%;

[0149] By the 31st day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 79.6%;

[0150] By the 35th day after the start of treatment, the actual COD removal rate of the high-concentration hemicellulose deep processing wastewater entering the secondary sedimentation tank was 80.9%.

[0151] After 35 days of acclimation, the COD of the effluent from high-concentration hemicellulose deep processing wastewater was about 1530 mg / L.

[0152] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for treating high-concentration hemicellulose deep processing wastewater, characterized in that: The high-concentration hemicellulose deep processing wastewater treatment system is used for treatment. The high-concentration hemicellulose deep processing wastewater treatment system comprises a blending tank (1), a collection tank (2), an aeration tank (3), an aeration tank (4), a first settling tank (5), a delayed aeration tank (6) and a second settling tank (7) which are connected in sequence, wherein: The facultative oxygen tank (3) is provided with a submersible mixer and is connected to the aeration tank (4). A sludge internal reflux channel is provided inside the facultative oxygen tank (3). The sludge outlet of the facultative oxygen tank (3) is connected to the sludge treatment process through a sludge pipeline, and the outlet of the facultative oxygen tank (3) for discharging H2S gas is connected to the waste gas treatment process; the aeration tank (4) is connected to the first sedimentation tank (5); the first sedimentation tank (5) is connected to the delayed aeration tank (6); the delayed aeration tank (6) is connected to the second sedimentation tank (7); the sludge outlet at the bottom of the second sedimentation tank (7) is connected to the delayed aeration tank (6) through a reflux sludge pipeline and is also connected to the sludge treatment process. ; The facultative aerobic tank (3) is injected with activated sludge, which comes from the residual activated sludge in the aerobic tank of the viscose fiber production enterprise and is salt-tolerant. The facultative aerobic tank is an anaerobic environment. Salt-tolerant facultative aerobic bacteria are domesticated in the facultative aerobic tank. The salt-tolerant facultative aerobic bacteria reduce sulfate in an environment without molecular oxygen or with little molecular oxygen, thereby reducing COD; The delayed aeration tank (6) is injected with activated sludge, which comes from the residual activated sludge in the aerobic tank of the viscose fiber production enterprise and is salt-tolerant. Salt-tolerant aerobic bacteria are domesticated in the delayed aeration tank. The salt-tolerant aerobic bacteria can adapt to the wastewater treated in the facultative aerobic tank and deeply decompose the residual broken chain organic matter; The method for treating high-concentration hemicellulose deep processing wastewater comprises the following steps: Step 1): On Day 1, perform the following steps: 1a) injecting clean water into the blending tank (1), the collecting tank (2), the first settling tank (5) and the aeration tank (4) respectively, until the liquid level reaches the overflow outlet of each of the above structures; Injecting activated sludge and clean water into the aerobic tank (3) until the liquid level reaches the overflow port of the aerobic tank (3), adjusting the activated sludge concentration to 3000-5000 mg / L, and then adding high-concentration hemicellulose deep processing wastewater separately to adjust the COD concentration in the aerobic tank (3) to 30-80 mg / L; Inject activated sludge and clean water into the delayed aeration tank (6) until the liquid level reaches the overflow port of the delayed aeration tank (6), adjust the activated sludge concentration to 2500-3500 mg / L, and then add high-concentration hemicellulose deep processing wastewater separately. The COD concentration in the delayed aeration tank (6) is controlled to 30-80 mg / L. Open the compressed air valve for aeration and control the dissolved oxygen to 2-4 mg / L. 1b) starting to continuously inject high-concentration hemicellulose deep processing wastewater into the blending tank (1), and maintaining the pH in the blending tank (1) at 7.5-8.5; Step 2): On the 2nd to 10th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank (3) by a pump, and then enters the aeration tank (4), the first sedimentation tank (5), the delayed aeration tank (6) and the second sedimentation tank (7) in sequence by gravity flow, wherein the flow control meets the following conditions: the residence time of the high-concentration hemicellulose deep processing wastewater in the aeration tank (3) is 5-7 days; the residence time of the high-concentration hemicellulose deep processing wastewater in the delayed aeration tank (6) is 11-13 days; The COD value of the high-concentration hemicellulose deep processing wastewater is 5000-8000 mg / L; The pH value of the high-concentration hemicellulose deep processing wastewater is 1.5-2.5; The dissolved oxygen concentration in the delayed aeration tank (6) is controlled to be 1.5-2.5 mg / L after the second day; Overall, after 35 days of acclimation, the COD removal rate of high-concentration hemicellulose deep processing wastewater can be maintained at 95.1%, and the effluent COD can be kept below 500 mg / L; During the acclimation process, the residence time of the aerobic tank and the delayed aeration tank gradually decreased.

2. The method for treating high-concentration hemicellulose deep processing wastewater according to claim 1, characterized in that: The process also includes step 3): On the 11th to 18th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank (3) and then flows into the aeration tank (4), the first sedimentation tank (5), the delayed aeration tank (6) and the second sedimentation tank (7) in sequence by gravity flow, wherein the flow control satisfies the following conditions: The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank (3) is 2-4 days; The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank (6) is 5-7 days.

3. The method for treating high-concentration hemicellulose deep processing wastewater according to claim 2, characterized in that: The process also includes step 4): On the 19th to 21st day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank (3) and then flows into the aeration tank (4), the first sedimentation tank (5), the delayed aeration tank (6) and the second sedimentation tank (7) in sequence by gravity flow, wherein the flow control satisfies the following conditions: The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank (3) is 2-3 days; The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank (6) is 4-6 days.

4. The method for treating high-concentration hemicellulose deep processing wastewater according to claim 3, characterized in that: The process also includes step 5): On the 22nd to 24th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank (3) and then flows into the aeration tank (4), the first sedimentation tank (5), the delayed aeration tank (6) and the second sedimentation tank (7) in sequence by gravity flow, wherein the flow control meets the following conditions: The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank (3) is 1-2 days; The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank (6) is 3-4 days.

5. The method for treating high-concentration hemicellulose deep processing wastewater according to claim 4, characterized in that: The process also includes step 6): On the 25th to 27th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank (3) and then flows into the aeration tank (4), the first sedimentation tank (5), the delayed aeration tank (6) and the second sedimentation tank (7) in sequence by gravity flow, wherein the flow control meets the following conditions: The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank (3) is 1.0-1.4 days; The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank (6) is 2.2-2.6 days.

6. The method for treating high-concentration hemicellulose deep processing wastewater according to claim 5, characterized in that: The process also includes step 7): On the 28th to 31st day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank (3) and then flows into the aeration tank (4), the first sedimentation tank (5), the delayed aeration tank (6) and the second sedimentation tank (7) in sequence by gravity flow, wherein the flow control satisfies the following conditions: The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank (3) is 0.8-1.0 day; The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank (6) is 1.7-1.9 days.

7. The method for treating high-concentration hemicellulose deep processing wastewater according to claim 6, characterized in that: The process also includes step 8): On the 32nd to 35th day, the high-concentration hemicellulose deep processing wastewater is continuously pumped to the aeration tank (3) and then flows into the aeration tank (4), the first sedimentation tank (5), the delayed aeration tank (6) and the second sedimentation tank (7) in sequence by gravity flow. Starting from the 36th day, the wastewater is treated according to the flow parameters of the 35th day, wherein the flow control meets the following conditions: The residence time of high-concentration hemicellulose deep processing wastewater in the aerobic tank (3) is 0.7-0.9 days; The residence time of high-concentration hemicellulose deep processing wastewater in the delayed aeration tank (6) is 1.5-1.7 days.

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