Resourceful treatment device for modified starch wastewater

Abstract

The utility model discloses a resourceful treatment device for modified starch wastewater, and belongs to the technical field of wastewater treatment. The utility model relates to a resourceful treatment device for modified starch wastewater. The device comprises a water collecting well, an accident tank, a first inclined plate sedimentation tank, a high-salt buffer tank, an aeration unit, an MBR (Membrane Bioreactor) unit, a flocculation unit, a second inclined plate sedimentation tank and a refrigerator which are connected in sequence, according to the resourceful treatment device for the modified starch wastewater, a biochemical and freezing combined technology is adopted, organic matters and salts in the modified starch wastewater can be fully separated, obtained starch cakes and salts obtained through freezing crystallization can be recycled, waste is turned into wealth, the treated wastewater can reach the emission standard, and the environment is protected. The green and environment-friendly requirements are met; the device provided by the utility model is high in flexibility and stability, can flexibly adjust the microbial biomass and the biological population structure according to the treatment load and the water quality change, and is suitable for industrial actual production and utilization.

Description

Technical Field

[0001] The utility model belongs to the technical field of wastewater treatment, and in particular relates to a resource treatment device for modified starch wastewater. Background Art

[0002] Modified starch is based on natural starch, using physical, chemical or enzymatic treatment to change the properties of natural starch, so as to meet the use requirements of other products. Chemical method is the most commonly used modification method. In the process of chemical modification of natural starch, the COD of process wastewater generated is as high as 20g / L; the sodium sulfate of raw water is as high as 20g / L. Due to the high sodium sulfate content, it cannot be treated by conventional anaerobic and aerobic processes. For the treatment of high sodium sulfate wastewater generated by modified starch production, the industry usually adopts evaporation, freezing and electrodialysis treatment processes. Specifically, the operation method of the evaporation method is: after collecting and caching the wastewater to be evaporated, it is gradually concentrated by preheating, one-stage or multi-stage evaporators, and sodium sulfate slurry is collected from the bottom of the evaporation chamber. The sodium sulfate slurry is dried by a centrifuge and a drying system to form sodium sulfate crystals. The steam condensate is collected and treated or discharged separately. The operation method of the freezing method is: after collecting and caching the wastewater to be frozen, it is cooled and crystallized by a freezing crystallizer, and the slurry is collected from the bottom of the crystallizer. The slurry is mainly sodium sulfate decahydrate, and the slurry can be further dried or used directly. The supernatant overflows to the subsequent treatment process. The operation method of the membrane filtration method is: the wastewater to be concentrated is subjected to nanofiltration or reverse osmosis to separate sodium sulfate from small molecules such as sodium chloride and propylene glycol to achieve the concentration of sodium sulfate in the wastewater. It can also be used in conjunction with an evaporator and a freezer evaporator.

[0003] However, the above methods all have certain problems. For example, the evaporation method and the freezing method both require a lot of energy consumption, and the construction and operation costs are high. At the same time, since the wastewater contains a large amount of organic matter, the evaporated / frozen crystals will contain more impurities, and there is a quality risk for secondary use. In addition, the clear liquid produced after evaporation / freezing still needs to further remove COD, nitrogen, phosphorus and other pollution factors before it can be discharged, and it still needs to be equipped with corresponding sewage treatment facilities. For example, in the membrane filtration method, in addition to the concentrated sodium sulfate, the concentrated liquid after membrane filtration still contains a large amount of organic matter and miscellaneous salts, which affects the reuse of the concentrated liquid; and there will also be considerable sodium sulfate and organic matter in the concentrated water after membrane filtration, which still needs to be further treated before it can be discharged; at the same time, the construction, operation and maintenance costs of membrane components are high.

[0004] In summary, the above three commonly used methods have high construction and operation costs; and the collected sodium sulfate crystals or sodium sulfate solutions contain impurities, which is not conducive to secondary utilization. Summary of the invention

[0005] The purpose of the utility model is to overcome the shortcomings of the prior art and provide a resource treatment device for modified starch wastewater.

[0006] To achieve the above purpose, the technical solution adopted by the utility model is: a resource treatment device for modified starch wastewater, the device comprises a water collection well, an accident pool, a first inclined plate sedimentation tank, a high salt buffer tank, an aeration unit, an MBR unit, a flocculation unit, a second inclined plate sedimentation tank, and a refrigerator connected in sequence;

[0007] Two mud hoppers arranged at 60 degrees are provided at the bottom of the second inclined plate sedimentation tank.

[0008] The resource recovery treatment device for modified starch wastewater provided by the utility model can effectively solve the difficulties in the treatment of modified starch wastewater. The resource recovery treatment device of the utility model has the characteristics of low cost, strong operability, stable and flexible operation, and can also reuse and purify the salt in the modified starch wastewater.

[0009] Specifically, the setting of a water collection well can reduce the investment in underground pumping stations and reduce costs. The setting of an accident pool and a high-salt buffer pool can improve the emergency buffering capacity of the device. The design of the first inclined plate sedimentation tank can reduce the starch content in high-salt wastewater, turning starch into treasure, and the obtained starch cake can be used or sold as feed. The introduction of the aeration unit can make full use of the characteristics of microbial adaptability and diversity, improve the characteristics of water quality at all levels, cultivate matching microorganisms in a targeted manner, and effectively improve the impact resistance of the device, thereby improving the stability and flexibility of the operation of the device. The introduction of the MBR unit can effectively solve the problem of poor sedimentation caused by high sodium sulfate in modified starch wastewater; and the MBR unit can perform simultaneous biochemical treatment while separating mud and water, further improving the treatment efficiency. The introduction of the flocculation unit and the second inclined plate sedimentation tank can effectively solve the problem of poor dehydration of high-salinity sludge, better perform solid-liquid separation, and improve treatment efficiency; in particular, it is further limited that two mud buckets arranged at 60 degrees are provided at the bottom of the second inclined plate sedimentation tank. Through the setting of the mud bucket, the second inclined plate sedimentation tank can be equipped with no bottom scraper, and the automatic timed intermittent mud discharge can be achieved through the pump and valve, and the mud discharge cycle and time are adjustable; and it can effectively separate the phosphorus-containing sludge after treatment in the flocculation tank, achieve the standard discharge of total phosphorus and realize the full automatic operation of the phosphorus removal process; in addition, it can also solve the problem that the residual sludge in the high-salinity wastewater aeration tank is difficult to dehydrate without the use of bag filter presses or spiral stacking machines. The introduction of the freezer can effectively realize the salt freezing crystallization recovery process, and the treated water obtained can also meet the discharge standards.

[0010] As the resource treatment device for modified starch wastewater of the utility model, the aeration unit comprises a first aeration tank and a second aeration tank; the high-salt buffer tank, the first aeration tank, the second aeration tank and the MBR unit are connected in sequence.

[0011] As the resource treatment device for modified starch wastewater of the utility model, the inner wall of the aeration unit is provided with a chilled water pipe, the bottom is provided with a blower and a microporous aerator, and the top is provided with a cooling tower.

[0012] After research, it is found that the first aeration tank and the second aeration tank are connected in sequence in the device, and the first aeration tank and the second aeration tank can be operated in series or in parallel, and can be operated simultaneously or partially; that is, the introduction of the first aeration tank and the second aeration tank can not only realize multi-stage aerobic treatment to fully utilize the characteristics of microbial adaptability and diversity, effectively improve the impact resistance of the device, but also significantly enhance the stability and flexibility of the device. The introduction of the chilled water pipe on the inner wall of the aeration unit can cool the aeration unit, and the cooling tower on the top can also circulate and cool the aeration unit to prevent the death of bacteria caused by excessive temperature in the aeration unit in summer.

[0013] As the resource treatment device for modified starch wastewater of the utility model, the aeration unit may further include a third aeration tank and a fourth aeration tank.

[0014] According to research, setting up 2-4 levels of aeration units for series operation can help cultivate microbial populations that adapt to different concentrations in aeration tanks at each level. For example, the microorganisms in the first aeration tank can effectively degrade high-COD wastewater into low-COD (<1000mg / L) wastewater, and the microorganisms in the second aeration tank can effectively reduce low-concentration wastewater to discharge standard wastewater; the mixed liquid between the aeration tanks is baffled and propelled without the need for additional power.

[0015] As the resource treatment device for modified starch wastewater of the utility model, an air hand valve and a pressure gauge are also provided on the top of the aeration unit. The setting of the air hand valve and the pressure gauge can be used to accurately adjust the aeration volume of each aeration tank.

[0016] As the resource treatment device for modified starch wastewater described in the utility model, the first aeration tank and the second aeration tank use fiberglass or epoxy coal tar paint as anti-corrosion coatings; the pipes in the first aeration tank and the second aeration tank use stainless steel pipes; the microporous aerator is fixed by integrally wrapping it with a concrete pier.

[0017] According to research, the use of the above materials or overall wrapping can reduce the corrosion of sodium sulfate in modified starch wastewater, extend the service life of the device and operational stability.

[0018] As the resource treatment device for modified starch wastewater of the utility model, the MBR unit comprises a first MBR pool and a second MBR pool; the aeration unit, the first MBR pool, the second MBR pool and the flocculation unit are connected in sequence.

[0019] As the resource treatment device for modified starch wastewater of the utility model, the MBR unit is provided with a microfiltration membrane assembly, and a backwash water tank is provided on the top of the pool.

[0020] According to research, due to the influence of sodium sulfate in the modified starch wastewater, sulfur-producing bacteria in the activated sludge in the aeration unit multiply in large numbers, forming a filamentous skeleton, and the SV30 of the activated sludge is above 90% for a long time, making it impossible to use a gravity sedimentation tank for efficient mud and water separation; this device is equipped with a microfiltration membrane assembly in the MBR unit, and the microfiltration membrane can separate mud and water, solving the problem of mud and water separation, improving the stability of system treatment, and reducing the floor space occupied by the mud and water separation process. The setting of the backwash water tank can facilitate the cleaning of the microfiltration membrane and avoid membrane clogging after use. Specifically, citric acid and sodium hypochlorite can be used for backwashing when cleaning the membrane in the backwash water tank.

[0021] As the resource treatment device for modified starch wastewater of the utility model, a microporous aeration head is also arranged at the bottom of the MBR unit.

[0022] According to research, the setting of microporous aeration head can not only flush the sludge attached to the surface of microfiltration membrane, but also enable the mud-water mixture to undergo further biochemical reaction in the MBR unit to reduce the emission concentration.

[0023] As the resource treatment device for modified starch wastewater of the utility model, the flocculation unit comprises a dosing tank and a reaction tank; the MBR unit, the dosing tank, the reaction tank and the second inclined plate sedimentation tank are connected in sequence.

[0024] As the resource treatment device for modified starch wastewater of the utility model, a paddle-type mixer is arranged in the dosing tank, and a frame-type mixer is arranged in the reaction tank.

[0025] After research, it was found that the flocculation unit includes a dosing tank and a reaction tank connected in sequence. Flocculants PAC and PAM are added to the dosing tank, and PAC is used to react with phosphorus-containing compounds to generate insoluble phosphorus-containing flocs. PAM is used to increase the total phosphorus in the effluent. The flocculation unit discharges water from the middle of the tank body, and a perforated aeration and stirring is set at the bottom of the flocculation unit and is opened regularly. This can solve the problem of long-term accumulation of dense sludge at the bottom of the flocculation unit.

[0026] As the resource treatment device for modified starch wastewater of the utility model, the paddle mixer and the frame mixer are made of stainless steel.

[0027] As the resource treatment device for modified starch wastewater of the utility model, the mud bucket of the second inclined plate sedimentation tank is made of glass fiber reinforced plastics and PP materials.

[0028] As the resource processing device for modified starch wastewater of the utility model, a mechanical grid and a submersible mixer are arranged in the water collection well.

[0029] As the resource processing device for modified starch wastewater described in the utility model, a submersible mixer is provided in the accident pool and the high-salt buffer pool.

[0030] According to research, the accident pool can be used as emergency storage for wastewater; the high-salt buffer pool can cache water quality and quantity and hydrolyze the large molecular organic matter in the wastewater into small molecules, thereby improving the treatment efficiency of the biochemical process. The HRT is generally 12h to 24h.

[0031] As the resource treatment device for modified starch wastewater described in the utility model, the inclined plate in the first inclined plate sedimentation tank is made of PP material, and the first inclined plate sedimentation tank adopts a steel concrete structure design.

[0032] According to research, the first inclined plate sedimentation tank can be used to remove insoluble starch from high-salt wastewater.

[0033] As the resource treatment device for modified starch wastewater of the utility model, a water distribution tank can also be introduced into the aeration unit. The water distribution tank is designed to mix and distribute high-salt and high-COD wastewater, land discharge wastewater, mud pressure clear liquid and other wastewaters. The water distribution tank uses a baffled full mixing propulsion method to mix the wastewater, and two independent hand valves are set at the outlet to realize the distribution of the wastewater.

[0034] Compared with the prior art, the beneficial effects of the utility model are:

[0035] First: The resource treatment device for modified starch wastewater provided by the utility model uses a combination of biochemical and freezing technology to fully separate organic matter and salt in modified starch wastewater. The obtained starch cake and salt obtained by freezing crystallization can be recycled, turning waste into treasure, and the treated wastewater can meet the discharge standard, that is, meet the requirements of green environmental protection;

[0036] Second: The utility model provides a resource treatment device for modified starch wastewater, which makes full use of the strong adaptability of wastewater treatment microorganisms. It uses aeration units, MBR units and other structures in combination to effectively stabilize the device and improve its impact resistance. The resulting device is highly flexible and can flexibly adjust the amount of microorganisms and the structure of biological populations according to changes in processing load and water quality, making it suitable for actual industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of the structure of a modified starch wastewater resource treatment device provided by an embodiment of the utility model;

[0038] 1-water collection well, 2-accident pool, 3-first inclined plate sedimentation tank, 4-high salt buffer pool, 5-first aeration tank, 6-second aeration tank, 7-first MBR tank, 8-second MBR tank, 9-dosing tank, 10-reaction tank, 11-second inclined plate sedimentation tank, 12-refrigerator;

[0039] 101-mechanical grid, 102-first submersible mixer; 201-second submersible mixer; 401-third submersible mixer; 501-microporous aerator, 502-blower, 503-water distribution tank, 504-cooling circulation tower, 505-air hand valve, 506-pressure gauge, 507-chilled water pipe; 701-microporous filter membrane assembly, 702-backwash tank; 901-paddle mixer; 1001-frame mixer;

[0040] 100-first lifting pump, 200-second lifting pump, 300-first sludge pump, 400-third lifting pump, 500-sludge return pump, 600-self-priming pump, 700-automatic valve, 800-second sludge pump;

[0041] 1301 - the first pipeline, 1302 - the second pipeline, 1303 - the third pipeline, 1304 - the fourth pipeline, 1305 - the fifth pipeline, 1306 - the sixth pipeline, 1307 - the seventh pipeline, 1308 - the eighth pipeline, 1309 - the ninth pipeline, 1310 - the tenth pipeline. DETAILED DESCRIPTION

[0042] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0043] Example

[0044] A resource treatment device for modified starch wastewater in this embodiment is shown in the schematic diagram of its structure. Figure 1 As shown;

[0045] The device comprises a water collection well 1, an accident pool 2, a first inclined plate sedimentation pool 3, a high-salt buffer pool 4, a first aeration pool 5, a second aeration pool 6, a first MBR pool 7, a second MBR pool 8, a dosing pool 9, a reaction pool 10, a second inclined plate sedimentation pool 11, and a refrigerator 12, which are connected in sequence; the water collection well 1 and the accident pool 2 are connected via a second pipeline 1302, and a first lift pump 100 and a second lift pump 200 are arranged on the second pipeline 1302; the high-salt buffer pool 4 and the first aeration pool 5 are connected via a third pipeline 1303, and a third lift pump 400 is arranged on the third pipeline 1303; the second MBR pool 8 and the dosing pool 9 are connected via a fifth pipeline 1305, and a self-priming pump 600 is arranged on the fifth pipeline 1305; the second inclined plate sedimentation pool 11 and the refrigerator 12 are connected via a sixth pipeline 1306;

[0046] Among them, a mechanical grid 101 is arranged on the top of the water collection well 1, and a first submersible mixer 102 is also arranged; a second submersible mixer 201 is arranged in the accident pool 2; a third submersible mixer 401 is arranged in the high-salt buffer pool 4; a chilled water pipe 507 and a water distribution pool 503 are arranged on the inner wall of the aeration unit, a blower 502 and a microporous aerator 501 are arranged at the bottom of the aeration unit, a cooling circulation tower 504 is arranged on the top, and an air hand valve 505 and a pressure gauge 506 are also arranged on the top; a microporous filtration membrane assembly 71 is arranged inside the MBR unit, and a backwash tank 702 is arranged on the top of the MBR unit; a paddle mixer 901 is arranged inside the dosing pool 9, and a frame mixer 1001 is arranged inside the reaction pool 10;

[0047] In addition, the modified starch wastewater is connected to the collection well 1 through the first pipe 1301 via the waste liquid outlet (not marked in the figure), and can also be connected to the high salt buffer tank 4 through the tenth pipe 1310 via the waste liquid outlet (not marked in the figure); the bottom of the second MBR tank 8 is connected to the sludge return pump 500 through the fifth pipe 1305; the bottom of the second inclined plate sedimentation tank 11 is connected to the second sludge pump 800 through the seventh pipe 1307, and an automatic valve 700 is provided on the seventh pipe 1307; the refrigerator 12 is connected to the crystallized salt recycling system (not marked in the figure) through the eighth pipe 1308, and is connected to the Pasteur metering tank (not marked in the figure) through the ninth pipe 1309.

[0048] Specifically, the utility model comprises the following steps during production:

[0049] (1) The modified starch wastewater is introduced into the water collection well 1 through the first pipe 1301, the water collection well 1 is roughly filtered through the mechanical grid 101, and homogenized through the first submersible mixer 102;

[0050] (2) The modified starch wastewater can be transported to the accident pool 2, the first inclined plate sedimentation pool 3, and the high-salt buffer pool 4 through the second pipeline 1302. The above pretreatment parts are mainly used for emergency use, removal of suspended matter, and water homogenization;

[0051] (3) The pretreated wastewater is pumped to the first aeration tank 5 and the second aeration tank 6 through the third pipeline 1303;

[0052] Specifically, the first aeration tank 5 retains high-salinity bacteria, and the cultivation of high-salinity bacteria is mainly divided into the following steps:

[0053] 1) Sludge source selection: take common activated sludge that has not been inactivated;

[0054] 2) Water injection: before sludge inoculation, add at least 50% of the maximum volume of low-concentration wastewater into the first aeration tank 5;

[0055] 3) Adding sludge: The activated sludge to be cultured is evenly added to the first aeration tank 5. The initial sludge concentration when the system is started is about 1000 mg / L. During the sludge inoculation process, the aeration system needs to be turned on throughout the process, which plays a role in both oxygenation and stirring;

[0056] 4) Activation: After the addition of mud is completed, the 400-sludge return pump is kept open for reflux, and the reflux flow rate is controlled according to the residence time; the mud and water mixture of the entire system is fully mixed and broken up by reflux to maintain a stable and uniform sludge concentration; the sludge activation is considered to be completed after the following properties appear in the aeration tank: A. The mud and water mixture changes from obvious mud and water separation to turbidity, and the inoculated sludge changes from granular or lumpy to flocculent. B. The mud and water mixture is earthy yellow and emits a slightly fishy smell. There is no obvious smell of rotten eggs. C. COD is reduced to below 200mg / L, and COD does not decrease after three consecutive tests.

[0057] (4) The wastewater treated in the second aeration tank 6 flows by gravity into the MBR unit. The MBR unit is provided with a microporous filtration membrane assembly 701 for mud-water separation, and a backwash tank 702 for backwashing the microfiltration membrane;

[0058] (5) The wastewater clear liquid separated by the MBR unit is transported to the dosing tank 9 and the reaction tank 10 through the self-priming pump 600 and the fourth pipeline 1304; a paddle mixer 901 is provided in the dosing tank 9; a frame mixer 101 is provided in the reaction tank 10; polyferric sulfate and polyacrylamide are added to the dosing tank 9 and the reaction tank 10 for dosing and phosphorus removal;

[0059] (6) The wastewater from the reaction tank 10 overflows into the second inclined plate sedimentation tank 11 for mud-water separation. The bottom of the second inclined plate sedimentation tank 11 is connected to the second sludge pump 800 via the seventh pipeline 1307, and an automatic valve 700 is provided on the seventh pipeline 1307. The refrigerator 12 is connected to the crystallized salt recycling system (not shown in the figure) via the eighth pipeline 1308, and is connected to the Pasteur metering tank (not shown in the figure) via the ninth pipeline 1309.

[0060] Finally, it should be noted that the above embodiments are for illustrating the technical solution of the utility model rather than limiting the protection scope of the utility model. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the utility model.

Claims

1. A resource treatment device for modified starch wastewater, characterized in that: The device comprises a water collection well, an accident pool, a first inclined plate sedimentation tank, a high-salt buffer tank, an aeration unit, an MBR unit, a flocculation unit, a second inclined plate sedimentation tank, and a refrigerator, which are connected in sequence; Two mud hoppers arranged at 60 degrees are provided at the bottom of the second inclined plate sedimentation tank.

2. The resource recovery treatment device for modified starch wastewater according to claim 1, characterized in that: The aeration unit comprises a first aeration tank and a second aeration tank; the high-salt buffer tank, the first aeration tank, the second aeration tank and the MBR unit are connected in sequence.

3. The resource recovery treatment device for modified starch wastewater according to claim 2, characterized in that: The inner wall of the aeration unit is provided with a chilled water pipe, the bottom is provided with a blower and a microporous aerator, and the top is provided with a cooling tower.

4. The resource recovery treatment device for modified starch wastewater according to claim 1, characterized in that: The MBR unit comprises a first MBR pool and a second MBR pool; the aeration unit, the first MBR pool, the second MBR pool and the flocculation unit are connected in sequence.

5. The resource treatment device for modified starch wastewater according to claim 4, characterized in that: The MBR unit is provided with a microfiltration membrane assembly and a backwash water tank is provided on the top.

6. The resource treatment device for modified starch wastewater according to claim 1, characterized in that: The flocculation unit comprises a dosing tank and a reaction tank; the MBR unit, the dosing tank, the reaction tank and the second inclined plate sedimentation tank are connected in sequence.

7. The resource treatment device for modified starch wastewater according to claim 6, characterized in that: A paddle-type stirrer is arranged in the dosing tank, and a frame-type stirrer is arranged in the reaction tank.

8. The resource treatment device for modified starch wastewater according to claim 1, characterized in that: A mechanical grid and a submersible mixer are arranged in the water collection well.

9. The resource treatment device for modified starch wastewater according to claim 1, characterized in that: Submersible mixers are provided in the accident pool and the high-salt buffer pool.

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