A fermentation wastewater treatment system

Abstract

The invention discloses a system for treating fermentation wastewater, which comprises a flocculation device, a solid-liquid separation device, and a membrane separation device; the fermentation wastewater is connected to the liquid inlet of the solid-liquid separation device through the flocculation device; the clear phase liquid outlet of the solid-liquid separation device is connected to the liquid inlet of the membrane separation device. The system performs reasonable graded treatment on the fermentation wastewater and is suitable for real-time treatment of large quantities of wastewater.

Description

Technical Field

[0001] The invention specifically relates to a system for treating fermentation wastewater, belonging to the field of sewage treatment. Background Art

[0002] At present, the wastewater treatment process is mainly based on multi-effect evaporation to remove salt and bacterial residues in the wastewater. The evaporated wastewater is treated biochemically, and the residue is mainly landfilled.

[0003] CN202881044U discloses a vitamin B2 production wastewater treatment system, including a water distribution regulating tank, a HAF anaerobic reaction tank, a FSBBR flow biological reaction tank, an ozone oxidation tank, a TBF secondary biochemical treatment tank, a sedimentation tank and a water outlet. The system mainly uses a biochemical method to treat wastewater to meet the discharge standards, but does not recover vitamin B2 in the wastewater.

[0004] CN 109081478 A relates to a fermentation liquid wastewater treatment device, comprising: a neutralization tank, used for neutralizing fermentation acid wastewater; a NaOH adding tank, connected to the neutralization tank, used for adding NaOH into the neutralization tank; an electrodialyzer, connected to the neutralization tank, used for electrodialysis desalination of the wastewater after the neutralization reaction; a divalent salt adding tank, connected to the dilute liquid side of the electrodialyzer, used for adding divalent salt to the desalted wastewater; a first flocculation tank, connected to the dilute liquid side of the electrodialyzer, used for flocculation treatment of the electrodialysis dilute liquid; a first solid-liquid separation device, connected to the first flocculation tank, used for solid-liquid separation treatment of the feed liquid after flocculation treatment in the first flocculation tank; a second flocculation tank, connected to the first solid-liquid separation device, used for flocculation treatment of the clear liquid obtained by the first solid-liquid separation device; a second solid-liquid separation device, connected to the second flocculation tank, used for flocculation treatment of the second The slurry after flocculation treatment in the flocculation tank is subjected to solid-liquid separation treatment; a first dryer is connected to the first solid-liquid separation device and / or the second solid-liquid separation device, and is used to dry the solid obtained by solid-liquid separation; a nanofiltration membrane is connected to the second solid-liquid separation device, and is used to concentrate and filter the clear liquid obtained by the second solid-liquid separation device; a first adsorption tower is connected to the concentrated liquid side of the nanofiltration membrane, and is filled with a first adsorbent, and is used to perform a first adsorption treatment on the nanofiltration concentrated liquid; a second adsorption tower is connected to the water production port of the first adsorption tower, and is filled with a second adsorbent, and is used to perform a second adsorption treatment on the water produced by the first adsorption tower; a second dryer is connected to the water production port of the second adsorption tower, and is used to dry the filtrate obtained in the second adsorption tower; and it also includes: a biochemical treatment system, which is connected to the nanofiltration membrane, and is used to perform a biochemical treatment on the clear liquid obtained by the nanofiltration membrane. However, the above system has the following shortcomings: First, since the existing technology mainly adopts a multi-effect concentration process to treat vitamin B2 fermentation production wastewater, a high-salt concentrate will be produced. Therefore, in this technology, the wastewater is first neutralized and then electrodialysis is performed for desalination. However, for actual production of tons of wastewater every day, it is not easy to perform electrodialysis on tons of wastewater at the same time, so the system is not easy to apply; second, vitamin B2 fermentation wastewater itself is acidic, and the first flocculation treatment is also carried out under pH conditions of 3-6. However, in this technology, after neutralization and electrodialysis, the subsequent first flocculation treatment requires adding a large amount of acid to lower the pH back. It is impossible to first utilize the advantageous condition that the vitamin B2 fermentation wastewater itself is acidic, which also causes complicated processes and waste of resources; third, the nanofiltration membrane filtrate needs to be subjected to two-stage adsorption towers, and the process system is relatively complicated. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a fermentation production wastewater treatment system in view of the deficiencies of the above-mentioned prior art. The system can treat large quantities of production wastewater in real time.

[0006] The technical solution adopted by the present invention to solve the above-mentioned problems is:

[0007] A fermentation wastewater treatment system comprises a flocculation device, a solid-liquid separation device and a membrane separation device; the fermentation wastewater is connected with the liquid inlet of the solid-liquid separation device through the flocculation device; the clear phase liquid outlet of the solid-liquid separation device is connected with the liquid inlet of the membrane separation device.

[0008] According to the above scheme, it also includes a biochemical treatment device, and the clear phase liquid outlet of the membrane separation device is connected with the liquid inlet of the biochemical treatment device.

[0009] According to the above scheme, it also includes an ion flotation machine, the clear phase liquid outlet of the solid-liquid separation device is connected to the liquid inlet of the ion flotation machine, and the clear phase liquid outlet of the ion flotation machine is connected to the liquid inlet of the membrane separation device.

[0010] According to the above scheme, a first drying device is also included, and the solid phase outlet of the solid-liquid separation device and the solid phase outlet of the ion flotation machine are both connected to the first drying device.

[0011] According to the above scheme, the flocculation device and the solid-liquid separation device are two-stage, the storage tank of the fermentation production wastewater is connected with the liquid inlet of the first-stage solid-liquid separation device through the first-stage flocculation device, the clear phase liquid outlet of the first-stage solid-liquid separation device is connected with the liquid inlet of the second-stage solid-liquid separation device through the second-stage flocculation device; the clear phase liquid outlet of the second-stage solid-liquid separation device is connected with the liquid inlet of the membrane separation device.

[0012] Furthermore, the first flocculation device includes a first mixing device and a first buffer tank connected in sequence, and the iron salt tank and the PAM storage tank are respectively connected to the first mixing device, and the first mixing device is connected to a storage tank for fermentation production wastewater; the second flocculation device includes a second mixing device and a second buffer tank connected in sequence, and the iron salt tank, the alkali liquid tank, and the PAM storage tank are connected to the second mixing device; the outlet of the second buffer tank is connected to the second solid-liquid separation device, and the outlet of the first buffer tank is connected to the first solid-liquid separation device.

[0013] Furthermore, the second-stage flocculation device is divided into two sections, a second buffer tank is provided between the two sections of the flocculation device, the clear phase liquid outlet of the first-stage solid-liquid separation device is connected to the liquid inlet of the first-stage flocculation device, the liquid outlet of the first-stage flocculation device is connected to the second buffer tank, the second buffer tank is connected to the liquid inlet of the second-stage flocculation device, and the liquid outlet of the second-stage flocculation device is connected to the liquid inlet of the second-stage solid-liquid separation device.

[0014] According to the above scheme, the first mixing device, the second mixing device, and the pre-adjusting pH device all use a plurality of pipeline mixers; the first mixing device uses two pipeline mixers, and the iron salt tank and the PAM storage tank are respectively connected to the two pipeline mixers; the second mixing device uses four pipeline mixers, which are connected to the alkali liquid storage tank, the iron salt tank, the alkali liquid tank, and the PAM storage tank in sequence; the pre-adjusting pH device is a pipeline mixer, and the hydrochloric acid storage tank is connected to the pipeline mixer.

[0015] According to the above scheme, the membrane separation device includes a pre-adjusting pH device and a nanofiltration membrane machine, the clear phase outlet of the solid-liquid separation device is connected to the pre-adjusting pH device; the clear liquid outlet of the nanofiltration membrane machine is connected to the biochemical treatment device, the concentrated liquid outlet of the nanofiltration membrane machine is connected to the inlet of the centrifugal separation device, the clear liquid outlet of the centrifugal separation device is connected to the biochemical treatment device, and the solid phase outlet of the centrifugal separation device is connected to the second drying device.

[0016] According to the above scheme, the biochemical treatment device includes an anaerobic activation tank, an anaerobic ammonia oxidation tank, an aerobic tank and a sedimentation tank connected in sequence, the clear liquid outlet of the nanofiltration membrane machine is connected to the anaerobic activation tank, and the clear liquid outlet of the centrifugal separation device is connected to the aerobic tank.

[0017] According to the above scheme, the outlet of the first drying device is connected to the first dust collector, the protein feed collecting device and the tail gas absorption device in sequence; the outlet of the second drying device is connected to the second dust collector, the crude vitamin B2 collector and the tail gas absorption device in sequence.

[0018] According to the above scheme, the centrifugal separation device adopts a disc centrifuge.

[0019] According to the above scheme, the outlet ends of the second drying device and the first drying device are connected to the same tail gas absorption device. The tail gas absorption device includes a cyclone separator, an ammonia removal tower, a H2S removal tower, and a plasma purifier which are connected in sequence.

[0020] According to the above scheme, the first solid-liquid separation device and the second solid-liquid separation device both adopt horizontal spiral centrifuges; the first drying device and the second drying device both adopt cyclone flash dryers.

[0021] According to the above scheme, the storage tank is used to store vitamin B2 fermentation production wastewater; the iron salt tank and the PAM storage tank are used to store iron salt solution and PAM solution respectively.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] First, compared with the fermentation wastewater treatment system involved in CN 109081478 A, the present invention abandons the idea of ​​reducing the NaCl concentration in the wastewater by electrodialysis so as to facilitate the interception of vitamin B2 by nanofiltration membrane. Instead, in order to separate the protein bacterial mud product from the vitamin B2 product, flocculation is directly performed to maintain the NaCl concentration in the wastewater, which is beneficial to ensure a higher solubility of vitamin B2 in the clear phase before nanofiltration membrane filtration, and then the crude vitamin B2 is recovered by nanofiltration membrane combined with centrifugal separation; at the same time, the effluent is guaranteed to meet environmental protection requirements. In this way, on the one hand, it is beneficial to quickly and massively treat wastewater in actual production, and on the other hand, the concentrated phase produced in membrane separation can also be dried and used as low-content VB2. There is no difficult-to-treat high-salt concentrated slurry problem in the entire system process; there is no need for adsorption and impurity removal steps, which is simpler and easier.

[0024] Second, in the flocculation process, the present invention first performs acid flocculation and then performs alkaline flocculation, which fully utilizes the acidity of the vitamin B2 fermentation wastewater itself and reduces costs. In addition, an ion flotation device can be added before the clear phase after flocculation enters the nanofiltration membrane to ensure the life of the nanofiltration membrane and further increase the yield of protein bacterial sludge.

[0025] Third, vitamin B2 wastewater contains a large amount of organic matter and SO4 2- They are all intercepted in the flocculation centrifugation and membrane separation stages. The clear liquid effluent index after nanofiltration membrane treatment can reach COD < 10000 mg / L, and the B / C value can reach 0.75. After subsequent anaerobic biochemical treatment, COD < 700 mg / L; after anaerobic ammonia oxidation process, the effluent COD ≤ 150 mg / L, ammonia nitrogen ≤ 100 mg / L, and total nitrogen ≤ 150 mg / L; after aerobic biochemical process, it can be guaranteed that the final effluent COD ≤ 70 mg / L, ammonia nitrogen ≤ 5 mg / L, and total nitrogen ≤ 20 mg / L.

[0026] Therefore, during the wastewater treatment process, the process system of the present invention can realize online real-time and rapid processing of large quantities of vitamin B2 wastewater, which not only extracts the bacterial protein feed and some residual VB2, but also all the tail gas and wastewater are centrally treated before discharge, which can ensure that the emission standards are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the processing system of the present invention.

[0028] Figure 2 The main process flow chart of the processing system of the present invention is shown in FIG. DETAILED DESCRIPTION

[0029] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with embodiments, but the present invention is not limited to the following embodiments.

[0030] The VB2 fermentation wastewater used in the following examples is mainly composed of biconical water, plate and frame water, equipment flushing water, domestic water, demineralized water or clean water in the fermentation production of VB2 in a pharmaceutical company. The specific water quality is shown in Table 1. After the above wastewaters are mixed, the pH value is about 5.6.

[0031]

[0032] In the following examples, the concentration of ferric chloride in the ferric chloride solution is 10% and the pH is 1.2-1.5.

[0033] Example 1

[0034] A treatment system for wastewater produced by fermentation of vitamin B2, comprising a first flocculation device, a first horizontal spiral centrifuge, a second flocculation device, a second horizontal spiral centrifuge, an ion floatation machine, a membrane separation device, and a biochemical treatment device, wherein:

[0035] The first flocculation device comprises two pipeline mixers connected in sequence and a first buffer tank; the storage tank is connected to the inlet of the first buffer tank through the two pipeline mixers connected in sequence, and the outlet of the first buffer tank is connected to the first horizontal spiral centrifuge; the iron salt tank and the PAM storage tank are respectively connected to the two pipeline mixers, and are used to introduce the iron salt solution and the PAM solution respectively; the solid phase outlet of the first horizontal spiral centrifuge is connected to the protein bacteria mud pool;

[0036] The second flocculation device comprises four pipeline mixers connected in sequence, a second buffer tank, and four pipeline mixers; the liquid phase outlet of the first horizontal spiral centrifuge is connected to the inlet of the second buffer tank through four pipeline mixers connected in sequence, and the outlet of the second buffer tank is connected to the second horizontal spiral centrifuge through four pipeline mixers connected in sequence; the alkali liquid tank, the iron salt tank, the alkali liquid tank, and the PAM storage tank are respectively connected to one of the two groups of four pipeline mixers, for introducing the iron salt solution and the PAM solution and controlling the mixed pH; the solid phase outlet of the second horizontal spiral centrifuge is connected to the protein bacteria mud pool; the liquid phase outlet of the second horizontal spiral centrifuge is connected to the inlet of the ion flotation machine;

[0037] The liquid phase outlet of the ion flotation machine is connected to the membrane separation device, and the solid phase outlet of the ion flotation machine is connected to the protein bacteria mud pool;

[0038] The membrane separation device comprises a pipeline mixer and a nanofiltration membrane machine connected in sequence, wherein the liquid phase outlet of the ion flotation machine is connected to the pipeline mixer, and the pipeline mixer is communicated with a hydrochloric acid storage tank to control the pH of the wastewater when entering the nanofiltration membrane machine; the clear liquid outlet of the nanofiltration membrane machine is connected to a biochemical treatment device; and the concentrated liquid outlet of the nanofiltration membrane machine is connected to a disc centrifuge;

[0039] The biochemical treatment device includes an anaerobic activation tank, an anaerobic ammonia oxidation tank, and an aerobic tank in sequence. The aerobic tank is connected to the outside through a sedimentation tank; the clear liquid outlet of the nanofiltration membrane machine is connected to the anaerobic activation tank; and the clear liquid outlet of the disc centrifuge is connected to the aerobic tank.

[0040] The solid phase outlet of the disc centrifuge is connected to the vitamin B2 crude product collector through a cyclone flash dryer, a cyclone dust collector and / or a cloth dust collector in sequence. The protein bacteria mud pool is connected to the protein feed collector through a cyclone flash dryer, a cyclone dust collector and / or a cloth dust collector in sequence. In addition, the dust collector outlet is connected to the tail gas absorption device, wherein the tail gas absorption device includes an atomizing condenser, a cyclone separator, an ammonia removal tower, an H2S removal tower, and a plasma purifier connected in sequence, and the plasma purifier is connected to the chimney through an induced draft fan.

[0041] The process of using the above system to treat wastewater from the production of vitamin B2 by fermentation is as follows:

[0042] Step 1: VB2 fermentation wastewater is mixed with drugs and acid flocculated through pipelines. The initial pH value of VB2 fermentation wastewater is about 5.6. First, ferric chloride solution is added through a pipeline mixer to adjust the pH to 4.3-4.5, and then polyacrylamide PAM solution is added through a pipeline mixer (the mass concentration of the PAM solution itself is 0.1%. After adding the pipeline, the concentration of PAM in the wastewater is 0.0025%, which is equivalent to a 40-fold dilution.), and then it passes through a buffer tank and enters a horizontal spiral centrifuge to separate the first protein bacterial mud I and obtain the first clear phase I;

[0043] Step 2: The first clear phase I obtained from the first horizontal spiral centrifuge enters the second pipeline for dosing and mixing for acidic flocculation. The first clear phase I is added with ferric chloride solution through a pipeline mixer to adjust the pH value to 4.3-4.5 (since the pH value of commercially available ferric chloride solution is 1.2-1.5, NaOH solution is first introduced before the addition of ferric chloride solution to ensure that the pH value of the solution system after mixing in the pipeline mixer is approximately between 4.8-5.0), and then polyacrylamide PAM solution is added through the pipeline mixer (the concentration and addition amount of PAM solution are the same as in the first step);

[0044] Step 3: The effluent from the pipeline treated in the second step is subjected to the third pipeline dosing, mixing and flocculation. After the effluent from the pipeline treated in the second step passes through the buffer tank, NaOH solution is added again through the pipeline mixer to adjust the pH in the pipeline to 8.8-9.0, and then ferric chloride solution is added to adjust the pH to 8.4-8.5 for the third flocculation, and then PAM solution is added for flocculation. The concentration and addition amount of PAM solution are the same as those in the first step, and then enter the secondary horizontal spiral centrifuge to separate the first protein bacterial mud II and the first clear phase II again;

[0045] Step 4: The first clear phase II is fed into an ion flotation machine to separate the first protein bacterial mud III and the first clear phase III;

[0046] Step 5: The first clear phase III is adjusted to pH 6.0 with hydrochloric acid in a pipeline mixer and then enters a nanofiltration membrane machine with a molecular weight cutoff of 250, and is separated into a second clear phase and a second dense phase; the second clear phase directly enters the anaerobic biochemical section of the biochemical system, and the second dense phase is separated by a disc centrifuge to obtain a third clear phase and a third dense phase; the third clear phase directly enters the aerobic biochemical section of the biochemical system;

[0047] Step 6: Drying process, including two parts, as follows: Part 1: After mixing and stirring the first protein bacterial mud I, II and III obtained by the two-stage horizontal spiral centrifuge, the mixture is sent to a cyclone flash dryer, and then through a dust collector to obtain a bacterial protein feed product (indicators are shown in Table 1), and the generated tail gas is discharged after passing through a tail gas treatment device; Part 2: The third dense phase obtained by the disc centrifuge is sent to a cyclone flash dryer, and then through a dust collector to obtain a VB2 product (indicators are shown in Table 2), with a purity of about 30%, and the generated tail gas is discharged after passing through a tail gas treatment device;

[0048] Step 7: Biochemical treatment. The second clear phase obtained by the nanofiltration membrane system (Note: after testing, the indicators are cod≈10000mg / L and total nitrogen≈900mg / L) directly enters the anaerobic biochemical section of the biochemical treatment system; after treatment in the anaerobic biochemical section, the indicators of the effluent are cod≈800mg / L and total nitrogen≈900mg / L, and then enters the anaerobic ammonium oxidation biochemical section for treatment, and the indicators of the effluent are cod≈300mg / L and total nitrogen≈150mg / L; then the effluent of the anaerobic ammonium oxidation biochemical section (this section uses anaerobic ammonium oxidizing bacteria, referred to as red bacteria) enters the aerobic biochemical section;

[0049] At the same time, the third clear phase obtained by the disc centrifuge contains a higher level of SO4 2- The concentration is about 20000mg / L (total amount is about 50T / d). In order to avoid the impact on the anaerobic biochemical part, it directly enters the later aerobic biochemical system (Note: it is mixed with the anaerobic ammonium oxidation section effluent that entered the aerobic biochemical section in the early stage and enters the aerobic biochemical section, just as a supplement to the carbon source of the aerobic biochemical section; and after dilution, SO4 2- The concentration is 1000mg / L, which will not affect the operation of the aerobic biochemical stage. ), the final effluent was tested, and the indicators were cod≈150mg / L and total nitrogen≈50mg / L, which met the discharge standards.

[0050] The physical and chemical indicators of the finished product of the bacterial protein feed obtained above are shown in Table 1.

[0051] Table 1

[0052]

[0053]

[0054] The above-mentioned VB2 finished product was tested by the National Feed Quality Supervision and Inspection Center (Wuhan), and the inspection report is shown in Table 2.

[0055] Table 2

[0056] Serial number Test items Test results Detection Methods 1 Vitamin B2 content (fluorescence spectrophotometry) <![CDATA[3.04×10 5 mg / kg]]> GB / T14701-2002 2 Crude protein content (Arbitration method) 63.73％ GB / T6432-1994

[0057] Example 2

[0058] The difference from Example 1 is that: the second flocculation device only includes four pipeline mixers connected in sequence and a second buffer tank; the liquid phase outlet of the first horizontal spiral centrifuge is connected to the inlet of the second buffer tank through four pipeline mixers connected in sequence, and the outlet of the second buffer tank is connected to the second horizontal spiral centrifuge; the alkali liquid tank, the iron salt tank, the alkali liquid tank, and the PAM storage tank are respectively connected to one of the four pipeline mixers for introducing iron salt solution and PAM solution and controlling the mixed pH; the solid phase outlet of the second horizontal spiral centrifuge is connected to the protein bacteria mud pool; the liquid phase outlet of the second horizontal spiral centrifuge is connected to the inlet of the ion flotation machine.

[0059] Example 3

[0060] The difference from Example 1 is that the liquid phase outlet of the second horizontal spiral centrifuge is connected to the inlet of the ion flotation machine through a pipeline mixer. The pipeline mixer is connected to the aluminum chloride tank for passing the aluminum chloride solution.

[0061] Example 4

[0062] The difference from Example 1 is that the first horizontal spiral centrifuge is omitted.

[0063] Example 5

[0064] The difference from Example 1 is that the ion floatation machine is omitted.

[0065] Example 6

[0066] The difference from Example 1 is that the first horizontal spiral centrifuge and the ion floatation machine are omitted.

[0067] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and changes without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A system for treating wastewater from vitamin B2 fermentation production, characterized in that It includes a first flocculation device, a first solid-liquid separation device, a second flocculation device, a second solid-liquid separation device, an ion floatation machine, a membrane separation device, a centrifugal separation device, a first drying device and a second drying device; The first flocculation device comprises a first mixing device and a first buffer tank which are connected in sequence, the iron salt tank and the PAM storage tank are respectively connected to the first mixing device, the first mixing device is connected to a storage tank of vitamin B2 fermentation production wastewater, and the outlet of the first buffer tank is connected to the liquid inlet of the first solid-liquid separation device; The second flocculation device comprises a first section of a second mixing device, a second buffer tank and a second section of a second mixing device connected in sequence; the iron salt tank, the alkali liquid tank and the PAM storage tank are respectively connected to the first section of the second mixing device, and the iron salt tank, the alkali liquid tank and the PAM storage tank are also respectively connected to the second section of the second mixing device; the clear phase liquid outlet of the first solid-liquid separation device is connected to the liquid inlet of the first section of the second mixing device; the liquid outlet of the first section of the second mixing device is connected to the second buffer tank, the second buffer tank is connected to the liquid inlet of the second mixing device, and the liquid outlet of the second section of the second mixing device is connected to the liquid inlet of the second solid-liquid separation device; The clear phase liquid outlet of the second solid-liquid separation device is connected to the liquid inlet of the ion flotation machine; The membrane separation device comprises a pre-adjusting pH device and a nanofiltration membrane machine which are connected in sequence; the clear phase liquid outlet of the ion flotation machine is connected to the pre-adjusting pH device of the membrane separation device, and the clear liquid outlet of the nanofiltration membrane machine is connected to the biochemical treatment device; the concentrated liquid outlet of the nanofiltration membrane machine is connected to the inlet of the centrifugal separation device, the clear liquid outlet of the centrifugal separation device is connected to the biochemical treatment device, and the solid phase outlet of the centrifugal separation device is connected to the first drying device; the outlet of the first drying device is connected to the second dust collector, the vitamin B2 crude product collector and the tail gas absorption device in sequence; The solid phase outlet of the first solid-liquid separation device, the solid phase outlet of the second solid-liquid separation device, and the solid phase outlet of the ion flotation machine are all connected to the second drying device; the outlet of the second drying device is sequentially connected to the first dust collector, the protein feed collection device and the tail gas absorption device.

2. The processing system according to claim 1, characterized in that The biochemical treatment device comprises an anaerobic activation tank, an anaerobic ammonia oxidation tank, an aerobic tank and a sedimentation tank which are connected in sequence. The clear liquid outlet of the nanofiltration membrane machine is connected to the anaerobic activation tank, and the clear liquid outlet of the centrifugal separation device is connected to the aerobic tank.

3. The processing system according to claim 1, characterized in that The outlet ends of the first drying device and the second drying device are connected to the same tail gas absorption device.

4. The processing system according to claim 1, characterized in that The first mixing device, the first stage of the second mixing device, the second stage of the second mixing device, and the pre-adjusting pH device all use a number of pipeline mixers; the first mixing device uses two pipeline mixers, and the iron salt tank and the PAM storage tank are respectively connected to the two pipeline mixers; the first stage of the second mixing device uses four pipeline mixers, which are sequentially connected to the alkali liquid storage tank, the iron salt tank, the alkali liquid tank, and the PAM storage tank; the second stage of the second mixing device uses four pipeline mixers, which are sequentially connected to the alkali liquid storage tank, the iron salt tank, the alkali liquid tank, and the PAM storage tank; the pre-adjusting pH device is a pipeline mixer, and the hydrochloric acid storage tank is connected to the pipeline mixer.

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