High-concentration degradation-resistant wastewater treatment system

Abstract

The high-concentration degradation-resistant wastewater treatment system comprises a hydrolysis acidification tank, an anaerobic reactor, an intermediate water tank, an aerobic granular sludge reaction tank and an MBR (membrane bioreactor) which are sequentially communicated in the wastewater flow direction, part of effluent of the anaerobic reactor flows back to the hydrolysis acidification tank for retreatment, and the rest of the effluent enters the intermediate water tank; the effluent of the middle water tank respectively enters an aerobic granular sludge reaction tank for decarbonization, denitrification and dephosphorization treatment and enters an MBR (Membrane Bioreactor) to make up the demand of denitrification on a carbon source; through coupling linkage and synergistic effect of the hydrolytic acidification reaction tank, the anaerobic reactor, the aerobic granular sludge reaction tank and the MBR bio-membrane reactor, the effluent concentration is controlled. A hydrolysis acidification pool and an anaerobic reactor are combined for internal circulation of a water outlet part, impact of high concentration on the anaerobic reactor is reduced, biogas produced by the anaerobic reactor is used for power generation, energy recovery and energy consumption saving, the purposes of energy conservation and emission reduction are achieved, and the problems that an existing treatment device and technology are tedious in process, long in hydraulic retention time and low in cost are solved. And meanwhile, the treatment effect is improved.

Description

Technical Field

[0001] The invention relates to the field of wastewater treatment, and in particular to a high-concentration refractory wastewater treatment system. Background Art

[0002] High-concentration and difficult-to-degrade organic wastewater generally refers to industrial wastewater such as coking wastewater, pharmaceutical wastewater, petrochemical / oil wastewater, textile / printing and dyeing wastewater, chemical wastewater, and paint wastewater. The so-called "high concentration" means that the organic matter concentration of this type of wastewater is relatively high, and the COD is generally above 2000mg / L, and some are even as high as tens of thousands to hundreds of thousands per liter; "difficult to degrade" means that the biodegradability of this type of wastewater is low, and the BOD5 / COD value is generally below 0.3 or even lower, and it is difficult to biodegrade. "High concentration" and "difficult to degrade" make it difficult to effectively treat this type of wastewater using "conventional" methods such as biological methods or physical and chemical methods alone. The presence of a large number of difficult-to-degrade organic pollutants in high-concentration difficult-to-degrade organic wastewater will make conventional biological treatment processes difficult to work, difficult-to-degrade organic pollutants cannot be effectively degraded, and the treated drainage cannot meet the emission standards, resulting in the entire treatment process failing to achieve the expected effect and purpose. In addition, the existing treatment devices and processes also have problems such as cumbersome processes, long hydraulic retention time, high investment costs, and large land area.

[0003] Therefore, it is necessary to solve the problems of the existing treatment devices and processes, such as complicated procedures, long hydraulic retention time, high investment costs, and large floor space, and at the same time, improve the treatment effect. Summary of the invention

[0004] The high-concentration difficult-to-degrade wastewater treatment system of the present invention solves the problems of complicated procedures, long hydraulic retention time, high investment cost, large floor space, etc. existing in existing treatment devices and processes, and at the same time improves the treatment effect.

[0005] The high-concentration refractory wastewater treatment system of the present invention comprises a hydrolysis acidification tank, an anaerobic reactor, an intermediate water tank, an aerobic granular sludge reaction tank and an MBR biofilm reactor which are sequentially connected and arranged along the wastewater flow direction. Part of the effluent of the anaerobic reactor is returned to the hydrolysis acidification tank for further treatment, and the remaining effluent enters the intermediate water tank. The effluent of the intermediate water tank enters the aerobic granular sludge reaction tank for decarbonization, denitrification and dephosphorization and enters the MBR biofilm reactor to make up for the demand for carbon source for denitrification.

[0006] Furthermore, the aerobic granular sludge reaction tank uses anaerobic granular sludge or flocculent sludge from the nitrogen and phosphorus removal process as the inoculated sludge, an aerator is arranged at the bottom of the tank, the gas flow rate on the sludge surface is 0.3-0.6cm / s, and the influent COD load is 0.2-0.75kg / m 3 .h;

[0007] Furthermore, the anaerobic reactor controls the pH value to 7.2-7.8, the temperature to 35-40°C, and the volume load to 6-10 kgCOD / m 3 .d; Control the B / C value of the effluent from the anaerobic reaction tank to 0.25-0.45, and the biogas generated by the anaerobic reactor is used for power generation;

[0008] Furthermore, the intermediate water tank returns 50-100% of the water volume treated per hour to the hydrolysis acidification tank for further treatment, 80-100% of the water volume treated per hour enters the aerobic granular sludge reaction tank, and 0-20% of the water volume treated per hour is discharged into the MBR biofilm reactor;

[0009] Furthermore, the aerobic granular sludge reaction tank adopts a sequencing batch process, operates for 6-8 hours per cycle, has a water exchange ratio of 0.25-0.4, and stops aeration when the reaction tank is filled with water, and starts to drain water at the same time. During the aeration, the dissolved oxygen in the tank is maintained at 2-4 mg / L, the sludge concentration in the tank is 8-12 g / L, and the sludge granulation is 20-40%;

[0010] Furthermore, the aerobic granular sludge reaction tank is provided with an image capturing device, and the opening and closing of the electric-controlled water inlet valve or the water discharge valve of the aerobic granular sludge reaction tank is controlled according to the captured sludge morphology;

[0011] Furthermore, the effluent of the aerobic granular sludge reaction tank flows into the MBR biofilm reactor by gravity, and the MBR biofilm reactor is aerated intermittently, with a pause of 0.5-1 hour for every 2-3 hours of aeration, and the dissolved oxygen concentration in the reactor during aeration is 2-4 mg / L;

[0012] Furthermore, the MBR biofilm reactor is provided with an adsorption material, the dosage of which is 0.05-0.2 m 3 / m 3 , control the sludge concentration in the MBR biofilm reactor to 5-8g / L, and discharge the excess sludge;

[0013] Furthermore, the adsorption material is activated carbon or activated coke particles.

[0014] The beneficial effects of the present invention are as follows: the high-concentration refractory wastewater treatment system of the present invention controls the effluent concentration through the coupling and linkage of the hydrolysis acidification reaction tank, the anaerobic reactor, the aerobic granular sludge reaction tank, and the MBR biofilm reactor, and the synergistic effect. The hydrolysis acidification tank and the anaerobic reactor are combined with the effluent part for internal circulation to reduce the impact of high concentration on the anaerobic reactor, and the anaerobic reactor uses the generated biogas for power generation, recovers energy, saves energy consumption, and achieves the purpose of energy conservation and emission reduction. Most of the effluent from the anaerobic reactor enters the aerobic granular sludge reaction tank, and a small part enters the MBR biofilm reactor, reducing the operating cost. The mature aerobic granular sludge has a larger particle size, and a unique aerobic-anoxic micro-region environment from the outside to the inside can be formed in the aerobic stage. Combined with the reactor sequencing batch anaerobic-aerobic operation mode, the removal of organic matter, nitrogen and phosphorus and the separation of mud and water can be completed in one reactor at the same time, reducing the volume of the tank body, reducing the area occupied by the tank body, and improving the effluent water quality and reducing membrane fouling. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0016] Figure 1 This is a process flow chart of the high-concentration difficult-to-degrade wastewater treatment process of the present invention. DETAILED DESCRIPTION

[0017] The high-concentration refractory wastewater treatment system of this embodiment includes a hydrolysis and acidification tank, an anaerobic reactor, an intermediate water tank, an aerobic granular sludge reaction tank and an MBR biofilm reactor which are sequentially connected and arranged along the wastewater flow direction. The effluent of the anaerobic reactor is partially returned to the hydrolysis and acidification tank for further treatment, and the remaining effluent enters the intermediate water tank. The effluent of the intermediate water tank enters the aerobic granular sludge reaction tank for decarbonization, denitrification and dephosphorization and enters the MBR biofilm reactor to make up for the demand for carbon source for denitrification. After the concentrated organic wastewater is balanced in the regulating tank for water quality and quantity, it enters the hydrolysis and acidification reaction tank. The hydrolysis and acidification reaction tank adopts an activated sludge process, and a plug-flow mixer is arranged in the tank. The wastewater flows to the anaerobic reactor, the intermediate water tank, the aerobic granular sludge reaction tank and the MBR biofilm reactor in sequence through the hydrolysis and acidification tank. The hydrolysis and acidification reaction tank, the anaerobic reactor, the aerobic granular sludge reaction tank and the MBR biofilm reactor are coupled and coordinated to control the effluent concentration. Most of the effluent from the anaerobic reactor enters the aerobic granular sludge reactor, and a small part enters the MBR biofilm reactor. The mature aerobic granular sludge in the aerobic granular sludge reactor has a larger particle size, and can form a unique aerobic-anoxic micro-zone environment from the outside to the inside in the aerobic stage. Combined with the reactor sequencing batch anaerobic-aerobic operation mode, the removal of organic matter, nitrogen and phosphorus and the separation of mud and water can be completed in one reactor at the same time.

[0018] In this embodiment, the aerobic granular sludge reaction tank uses anaerobic granular sludge or flocculent sludge from the nitrogen and phosphorus removal process as the inoculated sludge, an aerator is arranged at the bottom of the tank, the gas flow rate on the sludge surface is 0.3-0.6 cm / s, and the influent COD load is 0.2-0.75 kg / m 3 .h; Aerobic granular sludge, referred to as AGS, is a granular activated sludge formed by the self-agglomeration of microorganisms. Compared with ordinary activated sludge, it is less prone to sludge swelling, has strong impact resistance, can withstand high organic loads, and integrates microorganisms of different properties (aerobic, facultative anerobic and anaerobic microorganisms).

[0019] In this embodiment, the anaerobic reactor controls the pH value to 7.2-7.8, the temperature to 35-40°C, and the volume load to 6-10 kgCOD / m 3 .d; Control the B / C value of the effluent from the anaerobic reaction tank to 0.25-0.45, and the biogas produced by the anaerobic reactor is used for power generation; the anaerobic reactor utilizes anaerobic granular sludge technology, and provides sufficient rising velocity for the reactor through external circulation, maintains the expansion of the granular sludge bed and the mixing inside the reactor, and improves the treatment efficiency of the reactor. High-concentration wastewater is pumped into the bottom of the ECAR by the water distribution system, and is fully mixed with the anaerobic granular sludge in the reactor. Most of the organic matter is converted into biogas. The gas-liquid separation module separates the biogas, water and sludge well. The biogas enters the biogas delivery system from the top, and the wastewater flows into the subsequent treatment system from the outlet pipe, and the anaerobic sludge flows back to the sludge bed.

[0020] In this embodiment, 50-100% of the water treated per hour in the intermediate water tank is returned to the hydrolysis acidification tank for further treatment, 80-100% of the water treated per hour enters the aerobic granular sludge reaction tank, and 0-20% of the water treated per hour is discharged into the MBR biofilm reactor; the effluent part is circulated internally to reduce the impact of high concentration on the anaerobic reactor.

[0021] In this embodiment, the aerobic granular sludge reaction tank adopts a sequencing batch process, intelligently controls the operation state, operates for 6-8 hours per cycle, and has a water exchange ratio of 0.25-0.4. When the reaction tank is filled with water, aeration is stopped and drainage is started at the same time. During aeration, the dissolved oxygen in the tank is maintained at 2-4 mg / L, the sludge concentration in the tank is 8-12 g / L, and the sludge granulation is 20-40%; the aerobic granular sludge reaction tank is provided with an image shooting device, and the opening and closing of the electric control water inlet valve or the drain valve of the aerobic granular sludge reaction tank is controlled according to the sludge morphology photographed; the image shooting device adopts existing equipment. For example, an underwater camera is installed at 2 / 3-4 / 5 of the upper part of the wall of the aerobic granular sludge reaction tank, and the electric control water inlet valve or the drain valve of the aerobic granular sludge reaction tank is started or closed according to the sludge morphology photographed by the camera.

[0022] In this embodiment, the effluent of the aerobic granular sludge reaction tank flows into the MBR biofilm reactor by gravity. The MBR biofilm reactor is intermittently aerated, and the aeration is suspended for 0.5-1 hour every 2-3 hours. The dissolved oxygen concentration in the reactor during aeration is 2-4 mg / L; the MBR biofilm reactor is provided with an adsorption material, and the dosage is 0.05-0.2 m 3 / m 3 , control the sludge concentration in the MBR biofilm reactor to 5-8g / L, and discharge the excess sludge; the adsorption material is activated carbon or activated coke particles; the aerobic granular sludge effluent enters the MBR biofilm reactor, and at the same time, in order to reduce the addition of external carbon sources, the total nitrogen removal rate is improved. 0% to 20% of the anaerobic reactor effluent is discharged into the MBR biofilm reactor to reduce operating costs. Aerobic granular sludge integrates decarbonization, denitrification and phosphorus removal, reduces the volume of the pool, and reduces the area occupied by the pool. The sludge concentration of the MBR biofilm reactor is high. Adding powdered activated carbon to the reactor can not only improve the effluent quality, but also reduce membrane fouling.

[0023] In the above embodiment, the hydrolysis acidification tank + anaerobic reactor, the effluent part is circulated internally to reduce the impact of high concentration on the anaerobic reactor; most of the effluent from the anaerobic reactor enters the aerobic granular sludge reactor, and a small part enters the MBR biofilm reactor. The sludge granulation in the aerobic granular sludge reactor is 20% to 40%, and the mature aerobic granular sludge has a larger particle size. In the aerobic stage, a unique aerobic-anoxic micro-region environment from the outside to the inside can be formed. Combined with the reactor sequencing batch anaerobic-aerobic operation mode, the removal of organic matter, nitrogen and phosphorus and mud-water separation can be completed in one reactor at the same time. The effluent from the aerobic granular sludge reactor enters the MBR biofilm reactor. The biofilm reactor is intermittently aerated, which can degrade COD and remove total nitrogen. At the same time, in order to reduce the carbon source required for denitrification, 0% to 20% of the effluent from the anaerobic reactor is discharged into the MBR biofilm reactor to reduce operating costs. Aerobic granular sludge integrates decarbonization, denitrification and phosphorus removal, reduces the volume of the tank body, and reduces the area occupied by the tank body. The sludge concentration in the MBR biofilm reactor is high. Adding powdered activated carbon into the reactor can not only improve the effluent quality but also reduce membrane fouling.

[0024] Embodiment 1

[0025] The high-concentration refractory wastewater treatment system of the present invention is used to treat pulp and papermaking wastewater with COD of 8000-10000 mg / L, and the process steps are as follows:

[0026] S1. Hydrolysis and acidification tank: the mixed pulp and paper making water is discharged into the hydrolysis and acidification tank. A plug flow mixer is installed in the reaction tank. Flocculent sludge is added. The sludge volume SV30 is about 30%, and the hydraulic retention time is 6h.

[0027] S2. Anaerobic reactor, anaerobic reactor uses granular sludge, the temperature in the reactor is 35-38 degrees, pH is 7.2-7.5, ORP is -350--550, and the volume load is 8kgCOD / m 3 .d; 80% of the reactor effluent is returned to the hydrolysis acidification tank for further treatment according to the hourly treated water volume, 90% is discharged into the aerobic particle reaction tank, and 10% enters the MBR biofilm reactor. The anaerobic reactor effluent COD is 1200-1500mg / L.

[0028] S3. Aerobic granular sludge reaction tank, aerobic granular sludge reaction tank sludge particle size 30%, sludge concentration 9g / L, each cycle operation 6h, water change ratio 0.35, water inlet 1.5h, reaction time 4h, sedimentation time 0.5h, sludge load 0.1kgBOD / kgMLSS, aeration time dissolved oxygen in the tank 2.5 ~ 3mg / L. Aerobic granular sludge effluent COD 120 ~ 150mg / L.

[0029] S4. MBR biofilm reactor, aerobic granular sludge effluent enters the MBR biofilm reactor, the reactor sludge concentration is 5g / L, every 3h of aeration, stop aeration for 1h, 10% of the anaerobic reactor effluent enters the MBR biofilm reactor, during aeration, the dissolved oxygen in the biofilm reactor is 3-4mg / L. The COD of the effluent of the MBR biofilm reactor is ≤50mg / L.

[0030] Finally, the effluent COD of the MBR biofilm reactor was detected to be ≤50mg / L, ammonia nitrogen ≤3mg / L, total nitrogen ≤15mg / L, and SS ≤10mg / L, indicating that the effluent quality of high-concentration organic wastewater can be effectively guaranteed by the device and process of the present invention.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A high-concentration refractory wastewater treatment system, characterized by: It includes a hydrolysis acidification tank, an anaerobic reactor, an intermediate water tank, an aerobic granular sludge reaction tank and an MBR biofilm reactor which are sequentially connected along the wastewater flow direction. Part of the effluent from the anaerobic reactor is returned to the hydrolysis acidification tank for further treatment, and the rest of the effluent enters the intermediate water tank. The effluent from the intermediate water tank enters the aerobic granular sludge reaction tank for decarbonization, denitrification and phosphorus removal and enters the MBR biofilm reactor to make up for the demand for carbon source for denitrification.

2. The high-concentration refractory wastewater treatment system according to claim 1, characterized in that: The aerobic granular sludge reaction tank uses anaerobic granular sludge or flocculent sludge from the nitrogen and phosphorus removal process as the inoculated sludge. An aerator is arranged at the bottom of the tank. The gas flow rate on the sludge surface is 0.3-0.6cm / s, and the influent COD load is 0.2-0.75kg / m 3 .h.

3. The high-concentration refractory wastewater treatment system according to claim 2 is characterized in that: The anaerobic reactor controls the pH value to 7.2-7.8, the temperature to 35-40°C, and the volume load to 6-10 kgCOD / m 3 .d; Control the B / C value of the effluent from the anaerobic reaction tank to be 0.25-0.45, and the biogas generated by the anaerobic reactor is used for power generation.

4. The high-concentration refractory wastewater treatment system according to claim 1, characterized in that: The intermediate water tank returns 50-100% of the water volume treated per hour to the hydrolysis acidification tank for further treatment, 80-100% of the water volume treated per hour enters the aerobic granular sludge reaction tank, and 0-20% of the water volume treated per hour is discharged into the MBR biofilm reactor.

5. The high-concentration refractory wastewater treatment system according to claim 1 is characterized by: The aerobic granular sludge reaction tank adopts a sequencing batch process, runs for 6-8 hours per cycle, has a water exchange ratio of 0.25-0.4, and stops aeration when water enters the reaction tank, and starts draining water at the same time. During aeration, the dissolved oxygen in the tank is maintained at 2-4 mg / L, the sludge concentration in the tank is 8-12 g / L, and the sludge granulation is 20-40%.

6. The high-concentration refractory wastewater treatment system according to claim 5 is characterized by: The aerobic granular sludge reaction tank is provided with an image shooting device, and the opening and closing of the electric-controlled water inlet valve or the water discharge valve of the aerobic granular sludge reaction tank is controlled according to the photographed sludge morphology.

7. The high-concentration refractory wastewater treatment system according to claim 5, characterized in that: The effluent of the aerobic granular sludge reaction tank flows into the MBR biofilm reactor by gravity. The MBR biofilm reactor is aerated intermittently, and is suspended for 0.5-1 hour every 2-3 hours of aeration. During aeration, the dissolved oxygen concentration in the reactor is 2-4 mg / L.

8. The high-concentration refractory wastewater treatment system according to claim 7, characterized in that: The MBR biofilm reactor is provided with an adsorption material, with a dosage of 0.05-0.2m 3 / m 3 , control the sludge concentration in the MBR biofilm reactor to 5-8g / L, and discharge the excess sludge.

9. The high-concentration refractory wastewater treatment system according to claim 8, characterized in that: The adsorption material is activated carbon or activated coke particles.

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