Continuous flow aerobic granular sludge coal chemical wastewater treatment system and treatment method

Abstract

The invention discloses a continuous flow aerobic granular sludge coal chemical industry wastewater treatment system and method, and the system comprises a hardness removal inclined tube tank, an anoxic tank, an aerobic tank, a separation reflux device, a sedimentation tank and a Roots blower. The method comprises the following steps: S1, hardness removal treatment; s2, carrying out denitrification treatment; s3, nitrification and denitrification; s4, separating and refluxing; and S5, carrying out precipitation treatment. The continuous flow aerobic granular sludge sewage treatment system provided by the invention has the advantages that the sludge concentration of a mixed solution in a flowing state in the anoxic tank and the aerobic tank can reach 6-10g / L, the sludge volume index SVI30 can reach 50mL / g or below, the settling velocity is excellent, the denitrification effect of the sludge is effectively improved, and meanwhile, the sludge concentration is large, so that the sewage treatment efficiency is improved. The impact load of sewage can be effectively resisted, and the sewage treatment efficiency and stability are improved. And the generated sludge amount is less than that of a traditional activated sludge process, so that the subsequent sludge treatment cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical wastewater treatment, and particularly relates to a continuous-flow aerobic granular sludge coal chemical wastewater treatment system and a treatment method. BACKGROUND

[0002] The aerobic granular sludge (AGS) process generally adopts selection pressure, satiation-starvation alternating environment and carrier granulation strengthening technology. For coal chemical wastewater, the metal ions in the wastewater can be used for strengthening granulation, which is helpful for long-period stable growth of the granular sludge. For a single granular sludge, an aerobic zone, an anoxic zone and an anaerobic zone can be formed in the sludge, which is beneficial to denitrification and phosphorus removal of the microorganisms and lessens the sludge amount. Compared with the traditional activated sludge method, the aerobic granular sludge technology has the characteristics of small land occupation, good settling performance, high biomass concentration, high organic load resistance and no sludge bulking. In combination with the characteristics of the coal chemical wastewater, the present application has low modification threshold and difficulty, and can be used in engineering practice.

[0003] At present, the sequencing batch aerobic granular sludge technology (AGS-SBR) is realized in engineering application, but the treatment system thereof is complicated in operation, has small wastewater treatment capacity, large land occupation, low utilization rate of the reactor, and relatively high requirements for instruments and equipment and daily operation and management cost. The continuous-flow aerobic granular sludge method (AGS-CFR) still stays in the laboratory research stage and has not been used in large-scale engineering application. Under this background, it has high research value to realize granulation of flocculent sludge in a continuous-flow state by using the aerobic granular sludge technology. SUMMARY

[0004] A first object of the present application is to provide a continuous-flow aerobic granular sludge coal chemical wastewater treatment system.

[0005] A second object of the present application is to provide a continuous-flow aerobic granular sludge coal chemical wastewater treatment method.

[0006] The first object of the present application is implemented by the following technical scheme: a continuous-flow aerobic granular sludge coal chemical wastewater treatment system, comprising a hard inclined tube pool, an anoxic pool, an aerobic pool, a separation reflux device, a sedimentation pool and a Roots blower, The hard inclined tube pool comprises, in sequence, a sodium carbonate and liquid alkali stirring pool, a PAC stirring pool, a PAM stirring pool and an inclined tube pool, and a wastewater pipe is communicated with an inlet of the sodium carbonate and liquid alkali stirring pool; An outlet of the Roots blower is respectively communicated with an aeration pipe of the aerobic pool and an air inlet pipe of the separation reflux device through a first regulating valve and a second regulating valve; The overflow outlet of the inclined tube pool is connected to the anoxic inlet of the anoxic pool, the anoxic outlet of the anoxic pool is connected to the inlet of the aerobic pool, the outlet of the aerobic pool is connected to the inlet of the separator / reflux device, the reflux outlet of the separator / reflux device is connected to the anoxic inlet of the anoxic pool, and the overflow outlet of the separator / reflux device is connected to the inlet of the sedimentation tank. An ORP detector is installed inside the anoxic pool adjacent to the anoxic outlet, and a pH detector and a dissolved oxygen meter are installed inside the aerobic pool adjacent to its outlet. A carbon source addition pipe is connected to the inlet of the anoxic pool, and a carbon source control valve is installed on the carbon source addition pipe.

[0007] Furthermore, an anoxic inlet is provided at one end of the anoxic pool, and an anoxic outlet is provided at the other end of the anoxic pool; inside the anoxic pool between the anoxic inlet and the anoxic outlet, n first partitions are arranged in a staggered manner, and the n first partitions divide the interior of the anoxic pool into n+1 anoxic spaces, and a hyperboloid mixer is provided in each anoxic space. Furthermore, a baffle is provided in the anoxic space where the anoxic inlet is located, and a channel is left between the bottom end of the baffle and the bottom of the anoxic pool. Furthermore, the separation and return device includes a pool body, an air inlet pipe, and a return pipe. The pool body has a conical bottom, and an overflow port is provided on the upper side wall of the pool body. The return pipe is vertically arranged in the middle of the pool body, and the return port at the top of the return pipe is connected to the inlet of the anoxic pool through a pipeline. The air inlet pipe is arranged in the center of the return pipe, and the top of the air inlet pipe is connected to the outlet of the Roots blower through the second regulating valve. The bottom outlet of the air inlet pipe extends to the bottom of the return pipe.

[0008] Furthermore, a flared opening is provided at the bottom end of the return pipe, which is opposite to the bottom of the conical pool.

[0009] Furthermore, the sludge outlet of the inclined tube tank is connected to the inlet of the discharge pump, and the outlet of the discharge pump is connected to two paths: one path is connected to the sludge discharge pipe, and the other path is connected to the sodium carbonate and liquid alkali mixing tank through a circulation pipe.

[0010] The second objective of this invention is achieved by the following technical solution: a treatment method for a continuous flow aerobic granular sludge coal chemical wastewater treatment system, characterized by comprising the following steps: S1: Hardening process The chemical wastewater first enters the hardening removal inclined tube tank through the wastewater pipe, and then flows into the sodium carbonate and liquid alkali mixing tank, PAC mixing tank, and PAM mixing tank respectively. The dosage of the reagents is 150-200 mg / L for liquid alkali, 50-70 mg / L for sodium carbonate, 20-30 mg / L for PAC, and 3 mg / L for PAM, which achieve hardening removal, coagulation, and sedimentation treatment in sequence. After that, the wastewater undergoes preliminary separation of sludge and water in the inclined tube tank. S2: Denitrification treatment After the initial separation of S1 sludge and water, the liquid is subjected to denitrification treatment in an anoxic tank for 4-6 hours. During the treatment, an external carbon source is added through a carbon source addition pipe to adjust the carbon-nitrogen ratio of the wastewater in the anoxic tank to 4-6 and the oxygen reduction point to -100-50. In addition, a hyperboloid mixer is used to shear the sludge during the treatment to promote the formation of granular sludge. S3: Nitrification and Denitrification The sludge-water mixture after S2 denitrification treatment is sent to an aerobic tank and held for 18-22 hours. The dissolved oxygen in the aerobic tank is controlled at 2-4 mg / L and the pH is controlled at 7.5-8.5. The wastewater undergoes nitrification in the aerobic tank, and denitrification occurs simultaneously inside the granular sludge. S4: Separate reflux The mixture after S3 nitrification and denitrification is held in a separator reflux tank for 2-3 hours for sludge screening. Heavy sludge settles at the bottom of the separator reflux tank. Then, air is introduced at 600-900 Nm³ through the air inlet pipe. 3 / h, under the action of airflow, the heavy sludge is discharged through the return port and then enters the anoxic tank of S2 for circulation treatment; S5: Precipitation Treatment After S4 treatment, the light sludge discharged from the separation reflux device enters the sedimentation tank for solid-liquid separation, thereby achieving the separation of wastewater and light sludge.

[0011] Furthermore, in S1, the mixers of the sodium carbonate and liquid alkali mixing tank, the PAC mixing tank, and the PAM mixing tank have a power of 3KW and a rotation speed of 40-60rpm.

[0012] Furthermore, in S2, the external carbon source is sodium acetate, glucose, or methanol; the hyperboloid mixer has a diameter of 1.5 m, a power of 3.0 kW, and a rotation speed of 20-30 rpm.

[0013] Furthermore, when the pH value detected by the pH meter is lower than 7.5, the proportion of sodium carbonate added during process S1 is increased until the pH value reaches 7.5-8.5; when the pH value detected by the pH meter is higher than 8.5, the proportion of liquid alkali added is increased until the pH value reaches 7.5-8.5.

[0014] Furthermore, when the dissolved oxygen level detected by the dissolved oxygen meter is below 2 mg / L, the opening of the first regulating valve is increased until the dissolved oxygen level reaches 2-4 mg / L; when the dissolved oxygen level detected by the dissolved oxygen meter is above 4 mg / L, the opening of the first regulating valve is decreased until the dissolved oxygen level reaches 2-4 mg / L.

[0015] Advantages of this invention: 1) The continuous flow aerobic granular sludge coal chemical wastewater treatment system provided in this application is based on the A / O process in the existing wastewater treatment technology. The modification cost is extremely low, the application range is very wide, the denitrification effect is stronger, the granular sludge is more stable and has strong shock resistance, saves a lot of energy consumption, and significantly reduces the operating cost. 2) In the saturation-starvation theory, the alternation of short saturation periods and long starvation periods can change the hydrophobicity of microbial surfaces, promoting the secretion of extracellular polymeric substances (EPS), thereby promoting sludge granulation. Therefore, in the anoxic tank, only stirring is required, while the aerobic tank controls a low substrate concentration at the end. Sludge screening is achieved through a separation and return device, and heavy sludge is returned using airlift. The return process creates an alternating saturation-starvation environment. The hyperboloid mixer in the anoxic tank provides a certain shear force to the sludge, promoting the formation of granular sludge. Denitrification can also occur inside the granular sludge, and the carbon source required for denitrification is less. 3) After treatment by the continuous flow aerobic granular sludge wastewater treatment system provided in this application, the sludge concentration in the anoxic and aerobic tanks under flowing conditions can reach 6-10 g / L, and the sludge volume index (SVI) can be reduced. 30 It can achieve a sludge concentration of less than 50 mL / g, exhibiting excellent settling velocity and effectively improving sludge denitrification. Simultaneously, due to its high sludge concentration, it can effectively resist shock loads from wastewater, improving wastewater treatment efficiency and stability. Furthermore, it produces less sludge compared to traditional flocculent sludge biological treatment systems, which helps reduce subsequent sludge treatment costs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of Example 1.

[0017] Figure 2 for Figure 1 Top view.

[0018] In the picture: Except for the following components: 1. Hard inclined tube tank, 101. Sodium carbonate and liquid alkali mixing tank, 102. PAC mixing tank, 103. PAM mixing tank, 104. Inclined tube tank, 105. Wastewater pipe, 2. Anoxic tank, 201. Anoxic inlet, 202. Anoxic space, 203. Hyperbolic mixer, 204. Baffle, 205. First partition, 206. Aerobic tank, 3. Separator and return device, 401. Tank body, 402. Air inlet pipe, 403. Return pipe, 404. Bell mouth, 5. Sedimentation tank, 6. Roots blower, 7. First regulating valve, 8. Second regulating valve, 12. Carbon source addition pipe, 13. Carbon source control valve, 14. Discharge pump, 15. Sludge discharge pipe, 16. Circulation pipe. Detailed Implementation

[0019] 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, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: As Figure 1 and Figure 2 As shown, a continuous flow aerobic granular sludge coal chemical wastewater treatment system includes a hardened inclined tube tank 1, an anoxic tank 2, an aerobic tank 3, a separation reflux device 4, a sedimentation tank 5, and a Roots blower 6. The outlet of the Roots blower 6 is connected to the aeration pipe of the aerobic tank 3 and the air inlet pipe of the separation reflux device 4 through a first regulating valve 7 and a second regulating valve 8, respectively, and simultaneously supplies air to the aerobic tank 3 and the separation reflux device 4. The overflow outlet of the inclined tube tank 104 is connected to the anoxic inlet 201 of the anoxic tank 2. The anoxic outlet 202 of the anoxic tank 2 is connected to the inlet of the aerobic tank 3. The outlet of the aerobic tank 3 is connected to the inlet of the separator reflux device 4. The reflux outlet of the separator reflux device 4 is connected to the inlet of the anoxic tank 2. The overflow outlet of the separator reflux device 4 is connected to the inlet of the sedimentation tank 5. Under the suction effect of the airflow, the heavy sludge at the bottom of the separator reflux device 4 can be returned to the anoxic tank 2 through the reflux outlet. An ORP detector is installed inside the anoxic tank 2 adjacent to the anoxic outlet 202. A pH detector and a dissolved oxygen meter are installed inside the aerobic tank 3 adjacent to its outlet. The pH value and dissolved oxygen content of the wastewater can be detected by the pH detector and the dissolved oxygen meter. A carbon source addition pipe 12 is connected to the inlet of the anoxic tank 2. A carbon source control valve 13 is installed on the carbon source addition pipe 12. Carbon source can be added through the carbon source addition pipe 12 to adjust the carbon-nitrogen ratio of the wastewater.

[0021] The inclined tube tank 1 includes a sodium carbonate and liquid alkali mixing tank 101, a PAC mixing tank 102, a PAM mixing tank 103, and an inclined tube tank 104 connected in sequence. Wastewater pipe 105 is connected to the inlet of the sodium carbonate and liquid alkali mixing tank 101. During wastewater treatment, carbonate and alkali solutions, PAC, and PAM can be added to the sodium carbonate and liquid alkali mixing tank 101, PAC mixing tank 102, and PAM mixing tank 103 respectively to remove hardness and induce flocculation and sedimentation. Afterwards, solid-liquid separation occurs through the inclined tubes of the inclined tube tank 104, separating the heavy flocculated precipitate. The wastewater overflowing from the inclined tube tank 104 and the light flocculated precipitate then proceed sequentially through anoxic tank 2 for denitrification, aerobic tank 3 for nitrification, a separation and reflux device 4 for separation and reflux treatment, and sedimentation tank 5 for solid-liquid separation to complete the wastewater treatment process. The sludge outlet of the inclined tube tank 104 is connected to the inlet of the discharge pump 14. The outlet of the discharge pump 14 has two connections: one is connected to the sludge discharge pipe 15, and the other is connected to the sodium carbonate and liquid alkali mixing tank 101 through the circulation pipe 16. Most of the sludge discharged from the inclined tube tank 104 is pumped out of the system through the sludge discharge pipe 15 after being pumped out by the discharge pump 14. A small portion of the sludge is sent back to the sodium carbonate and liquid alkali mixing tank 101 through the circulation pipe 16 to provide a coagulation nucleus and save on the amount of reagents added.

[0022] Specifically, an anoxic inlet 201 is provided at one end of the anoxic pool 2, and an anoxic outlet 202 is provided at the other end. Inside the anoxic pool 2 between the anoxic inlet 201 and the anoxic outlet 202, n staggered first partitions 206 are provided, dividing the interior of the anoxic pool 2 into n+1 anoxic spaces 203. A hyperboloid mixer 204 is provided in each anoxic space 203. A baffle 205 is provided in the anoxic space 203 where the anoxic inlet 201 is located, opposite to the anoxic inlet 201. A channel is left between the bottom of the baffle 205 and the bottom of the anoxic pool 2. Wastewater from the rigid inclined tube tank 1 and heavy sludge returned from the separator 4 enter the anoxic tank 2 through the anoxic inlet 201. Under the action of baffle 205, it enters the first anoxic space 203 from the lower right and upward. There, it is sheared and mixed by the hyperboloid mixer 204. Then, as it passes through each of the first baffles 206, denitrification occurs, and finally, it is discharged from the anoxic outlet 202 into the aerobic tank 3. The multiple first baffles 206 extend the nitrification reaction time and ensure more uniform shearing of the sludge particles, guaranteeing effective sludge granulation.

[0023] The separation and return device 4 includes a pool body 401, an air inlet pipe 402, and a return pipe 403. The pool body 401 has a conical bottom, and an overflow port is provided on the upper side wall of the pool body 401. The return pipe 403 is vertically arranged in the middle of the pool body 401. The return port at the top of the return pipe 403 is connected to the inlet of the anoxic pool 2 through a pipeline. An air inlet pipe 402 is arranged in the center of the return pipe 403. The top of the air inlet pipe 402 is connected to the outlet of the Roots blower 6 through a second regulating valve 8. The bottom outlet of the air inlet pipe 402 extends to the bottom of the return pipe 403. The mixture of wastewater and sludge from aerobic tank 3 undergoes solid-liquid separation within tank 401. Heavy sludge settles at the bottom of the conical tank, while light sludge and wastewater are discharged through the overflow outlet. Meanwhile, gas from air inlet pipe 402 is discharged downwards, creating a suction effect that causes the heavy sludge to rise along return pipe 403 and ultimately return to anoxic tank 2. A funnel-shaped opening 404, positioned opposite the conical tank bottom, is located at the bottom of return pipe 403 to facilitate the collection of heavy sludge. Simultaneously, gas from air inlet pipe 402 can flow along the inner wall of funnel opening 404 to the outer side of return pipe 403, separating the heavy sludge from the airflow and reducing disturbance to the heavy sludge at the bottom of tank 401. The inner diameter ratio of air inlet pipe 402 to return pipe 403 is 1:3-5. In this embodiment, the separation reflux device 4 utilizes air lift to achieve sludge reflux, reducing the shear force during the reflux process and preventing the breakage of granular sludge. The reflux process is gentle and uniform, making it suitable for protecting granular sludge with high structural integrity.

[0024] In this embodiment, the aerobic tank 3 is a plug-flow aerobic tank. The aeration pipe is fixedly installed at the bottom of the aerobic tank to provide aeration from bottom to top, providing shear force for the formation of granular sludge. At the same time, there is a substrate concentration gradient in the plug-flow aerobic tank. At the end of the aerobic tank, the substrate concentration is very low, and a large amount of microbial extracellular polymers (EPS) are secreted, so the flocculent sludge self-flocculates, promoting the sludge granulation process.

[0025] Example 2: A treatment method for a continuous flow aerobic granular sludge coal chemical wastewater treatment system based on Example 1, comprising the following steps: S1: Hardening process The chemical wastewater first enters the hard inclined tube tank 1 through wastewater pipe 105, and then flows into the sodium carbonate and liquid alkali mixing tank 101, PAC mixing tank 102, and PAM mixing tank 103 respectively. The dosage of the reagents is 150-200 mg / L for liquid alkali, 50-70 mg / L for sodium carbonate, 20-30 mg / L for PAC, and 3 mg / L for PAM (which can be adjusted according to the actual water quality). The mixers in the sodium carbonate and liquid alkali mixing tank 101, PAC mixing tank 102, and PAM mixing tank 103 have a power of 3KW and a speed of 40-60rpm. Wastewater is mixed and reacted with the added reagents in the sodium carbonate and liquid alkali mixing tank 101, PAC mixing tank 102, and PAM mixing tank 103, achieving hardening removal, coagulation, and sedimentation treatment in sequence. Afterward, it undergoes preliminary sludge-water separation in the inclined tube tank 104. The separated sludge is pumped out by the discharge pump 14 and divided into two paths. One path is discharged out of the system through the sludge discharge pipe 15, and the other path is sent back to the sodium carbonate and liquid alkali mixing tank 101 through the circulation pipe 16 to provide a coagulation nucleus for it, thus saving the amount of reagent added.

[0026] S2: Denitrification treatment The liquid discharged from the inclined tube tank 104 after the initial separation of sludge and water in S1 contains nitrate nitrogen. After being retained in the anoxic tank for 4-6 hours for denitrification, an external carbon source is added through the carbon source addition pipe 12 during the treatment process. The carbon-to-nitrogen ratio (C / N ratio) of the wastewater in the anoxic tank is adjusted to 4-6, and the oxygen reduction point (ORP) is adjusted to 100-50. If the C / N ratio is less than 4, the opening of the carbon source control valve 13 is increased to increase the amount of external carbon source added; if the C / N ratio is greater than 6, the opening of the carbon source control valve 13 is decreased to reduce the amount of external carbon source added. By rationally controlling the C / N ratio, denitrification efficiency can be guaranteed. Furthermore, the hyperboloid mixer uses a shearing action on the sludge during the treatment process to promote the formation of granular sludge. The external carbon source is sodium acetate, glucose, or methanol; the hyperboloid mixer has a diameter of 1.5 m, a power of 3.0 kW, and a speed of 20-30 rpm.

[0027] When the ORP (oxygen reduction potential) detected by the ORP detector is lower than 50, the opening of the carbon source control valve 13 is reduced to reduce the amount of carbon source added until the ORP reaches -100-50, and then the opening of the carbon source control valve 13 is restored. When the OPR (oxygen reduction potential) detected by the ORP detector is higher than 100, the opening of the carbon source control valve 13 is increased to increase the carbon source dosage until the ORP reaches -100-50, and then the opening of the carbon source control valve 13 is restored. S3: Nitrification and Denitrification The sludge-water mixture after S2 denitrification treatment is sent to an aerobic tank and held for 18-22 hours. The dissolved oxygen in the aerobic tank is controlled at 2-4 mg / L and the pH is controlled at 7.5-8.5. The wastewater undergoes nitrification in the aerobic tank, and denitrification occurs simultaneously inside the granular sludge. When the pH value detected by the pH meter is lower than 7.5, increase the sodium carbonate addition ratio in process S1 until the pH value reaches 7.5-8.5; when the pH value detected by the pH meter is higher than 8.5, increase the liquid alkali addition ratio until the pH value reaches 7.5-8.5.

[0028] When the dissolved oxygen level detected by the dissolved oxygen meter is below 2 mg / L, the opening of the first regulating valve 7 is increased until the dissolved oxygen level reaches 2-4 mg / L; when the dissolved oxygen level detected by the dissolved oxygen meter is above 4 mg / L, the opening of the first regulating valve 7 is decreased until the dissolved oxygen level reaches 2-4 mg / L.

[0029] S4: Separate reflux The mixture after S3 nitrification and denitrification is held in the separator reflux tank 4 for 2-3 hours to screen the sludge. The heavy sludge settles at the bottom of the separator reflux tank 4. Then, air is introduced at 600-900 Nm³ through the air inlet pipe. 3 / h, under the action of airflow, the heavy sludge is discharged through the return port and then enters the anoxic tank of S2 for circulation treatment; S5: Precipitation Treatment After treatment at S4, the light sludge discharged from the separation return device enters sedimentation tank 5 for solid-liquid separation, achieving the separation of wastewater and light sludge. The light sludge, after settling in sedimentation tank 5, is discharged from the system as excess sludge.

[0030] During wastewater treatment, water can be continuously fed in through wastewater pipe 105. Light sludge (such as flocculent sludge) slowly flows out from the bottom of sedimentation tank 5, while heavy sludge (such as granular sludge) remains in the system. The amount of light sludge discharged can be controlled by adjusting the sedimentation time in the separation return device 4, thus maintaining the sludge activity within the system. Heavy sludge is returned via airlift using air inlet pipe 402 and return pipe 403, preventing granular sludge from being crushed due to excessive shearing and disrupting the granulation process. This process increases the proportion of granular sludge during operation, improving wastewater treatment quality under continuous flow conditions. Effluent ammonia nitrogen, total nitrogen, total phosphorus, and COD are more easily met, and the sludge is more resistant to shock loads. In this embodiment, the sludge concentration in the anoxic and aerobic tanks under flowing conditions can reach 6–10 g / L, and the sludge volume index (SVI) is [not specified]. 30 It can reach concentrations below 50 mL / g, exhibiting excellent settling velocity and effectively improving the denitrification effect of sludge. At the same time, due to the high sludge concentration, it can effectively resist the shock load of wastewater, thereby improving wastewater treatment efficiency and stability.

[0031] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "front", "rear", "top", "bottom", "left", "right", "vertical", "horizontal", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

Claims

1. A continuous flow aerobic granular sludge coal chemical wastewater treatment system, characterized in that, It includes a rigid inclined tube tank, an anoxic tank, an aerobic tank, a separation reflux device, a sedimentation tank, and a Roots blower. The hardened inclined tube tank includes a sodium carbonate and liquid alkali stirring tank, a PAC stirring tank, a PAM stirring tank, and an inclined tube tank connected in sequence, and the wastewater pipe is connected to the inlet of the sodium carbonate and liquid alkali stirring tank. The outlet of the Roots blower is connected to the aeration pipe of the aerobic tank and the air inlet pipe of the separator through the first regulating valve and the second regulating valve, respectively. The overflow outlet of the inclined tube pool is connected to the anoxic inlet of the anoxic pool, the anoxic outlet of the anoxic pool is connected to the inlet of the aerobic pool, the outlet of the aerobic pool is connected to the inlet of the separator / reflux device, the reflux outlet of the separator / reflux device is connected to the anoxic inlet of the anoxic pool, and the overflow outlet of the separator / reflux device is connected to the inlet of the sedimentation tank. An ORP detector is installed inside the anoxic pool adjacent to the anoxic outlet, and a pH detector and a dissolved oxygen meter are installed inside the aerobic pool adjacent to its outlet. A carbon source addition pipe is connected to the inlet of the anoxic pool, and a carbon source control valve is installed on the carbon source addition pipe.

2. The continuous flow aerobic granular sludge coal chemical wastewater treatment system according to claim 1, characterized in that, An anoxic inlet is provided at one end of the anoxic pool, and an anoxic outlet is provided at the other end of the anoxic pool; n first partitions are arranged alternately on the left and right sides inside the anoxic pool between the anoxic inlet and the anoxic outlet, and the n first partitions divide the interior of the anoxic pool into n+1 anoxic spaces, and a hyperboloid mixer is provided in each anoxic space.

3. The continuous flow aerobic granular sludge coal chemical wastewater treatment system according to claim 2, characterized in that, A baffle is provided in the anoxic space where the anoxic inlet is located, and a channel is left between the bottom end of the baffle and the bottom of the anoxic pool.

4. The continuous flow aerobic granular sludge coal chemical wastewater treatment system according to claim 1, characterized in that, The separation and return device includes a pool body, an air inlet pipe, and a return pipe. The pool body has a conical bottom, and an overflow port is provided on the upper side wall of the pool body. The return pipe is vertically arranged in the middle of the pool body, and the return port at the top of the return pipe is connected to the inlet of the anoxic pool through a pipeline. The air inlet pipe is arranged in the center of the return pipe, and the top of the air inlet pipe is connected to the outlet of the Roots blower through the second regulating valve. The bottom outlet of the air inlet pipe extends to the bottom of the return pipe.

5. The continuous flow aerobic granular sludge coal chemical wastewater treatment system according to claim 4, characterized in that, A flared opening is provided at the bottom end of the return pipe, which is opposite to the bottom of the conical pool.

6. The continuous flow aerobic granular sludge coal chemical wastewater treatment system according to claim 4, characterized in that, The sludge outlet of the inclined tube tank is connected to the inlet of the discharge pump. The outlet of the discharge pump is connected to two paths: one path is connected to the sludge discharge pipe, and the other path is connected to the sodium carbonate and liquid alkali mixing tank through a circulation pipe.

7. A treatment method based on the continuous flow aerobic granular sludge coal chemical wastewater treatment system according to any one of claims 1 to 6, characterized in that, It includes the following steps: S1: Hardening process The chemical wastewater first enters the hardening removal inclined tube tank through the wastewater pipe, and then flows into the sodium carbonate and liquid alkali mixing tank, PAC mixing tank, and PAM mixing tank respectively. The dosage of the reagents is 150-200 mg / L for liquid alkali, 50-70 mg / L for sodium carbonate, 20-30 mg / L for PAC, and 3 mg / L for PAM, which achieve hardening removal, coagulation, and sedimentation treatment in sequence. After that, the wastewater undergoes preliminary separation of sludge and water in the inclined tube tank. S2: Denitrification treatment After the initial separation of S1 sludge and water, the liquid is subjected to denitrification treatment in an anoxic tank for 4-6 hours. During the treatment, an external carbon source is added through a carbon source addition pipe to adjust the carbon-nitrogen ratio of the wastewater in the anoxic tank to 4-6 and the oxygen reduction point to -100-50. In addition, a hyperboloid mixer is used to shear the sludge during the treatment to promote the formation of granular sludge. S3: Nitrification and Denitrification The sludge-water mixture after S2 denitrification treatment is sent to an aerobic tank and held for 18-22 hours. The dissolved oxygen in the aerobic tank is controlled at 2-4 mg / L and the pH is controlled at 7.5-8.

5. Nitrification occurs in the wastewater in the aerobic tank, and denitrification occurs simultaneously inside the granular sludge. S4: Separate reflux The mixture after S3 nitrification and denitrification is held in a separator reflux tank for 2-3 hours for sludge screening. Heavy sludge settles at the bottom of the separator reflux tank. Then, air is introduced at 600-900 Nm³ through the air inlet pipe. 3 / h, under the action of airflow, the heavy sludge is discharged through the return port and then enters the anoxic tank of S2 for circulation treatment; S5: Precipitation Treatment After S4 treatment, the light sludge discharged from the separation reflux device enters the sedimentation tank for solid-liquid separation, thereby achieving the separation of wastewater and light sludge.

8. The method for treating continuous flow aerobic granular sludge coal chemical wastewater according to claim 7, characterized in that, In S1, the mixers of the sodium carbonate and liquid alkali mixing tank, the PAC mixing tank, and the PAM mixing tank have a power of 3KW and a rotation speed of 40-60rpm.

9. The method for treating continuous flow aerobic granular sludge coal chemical wastewater according to claim 7, characterized in that, In S2, the external carbon source is sodium acetate, glucose, or methanol; the hyperboloid mixer has a diameter of 1.5 m, a power of 3.0 kW, and a rotation speed of 20-30 rpm.

10. A method for treating continuous flow aerobic granular sludge coal chemical wastewater according to claim 7, characterized in that, When the pH value detected by the pH meter is lower than 7.5, increase the sodium carbonate addition ratio in process S1 until the pH value reaches 7.5-8.5; when the pH value detected by the pH meter is higher than 8.5, increase the liquid alkali addition ratio until the pH value reaches 7.5-8.

5.

11. The method for treating continuous flow aerobic granular sludge coal chemical wastewater according to claim 7, characterized in that, When the dissolved oxygen level detected by the dissolved oxygen meter is below 2 mg / L, the opening of the first regulating valve is increased until the dissolved oxygen level reaches 2-4 mg / L; when the dissolved oxygen level detected by the dissolved oxygen meter is above 4 mg / L, the opening of the first regulating valve is decreased until the dissolved oxygen level reaches 2-4 mg / L.

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