CN219010084U - Dairy wastewater treatment system - Google Patents

Abstract

The technical field of sewage treatment of this application, in particular, relates to a treatment system for dairy wastewater. The treatment system includes a pretreatment unit, a biochemical treatment unit and an advanced treatment unit arranged in sequence. Pretreatment units are used to remove impurities from dairy wastewater. The biochemical treatment unit includes anaerobic reactors, multi-stage biological pools and secondary sedimentation tanks arranged in sequence. The multi-stage biological pools include pre-anoxic areas, anaerobic areas, anoxic first areas, aerobic first areas, and degassing areas. The first zone, the second anoxic zone, the second aerobic zone and the second degassing zone, the pre-anoxic zone is located at the back end of the anaerobic reactor, and the secondary settling tank is located at the back end of the second degassing zone. The advanced treatment unit is used to treat the total phosphorus and SS in the wastewater after the secondary sedimentation tank. The treatment system enables the effluent quality to reach the standard stably and meet the reuse water standard, which can be reused for landscaping, road watering, river water replenishment, industrial enterprise circulating cooling water replenishment, etc., and can realize the utilization of sewage resources.

Description

Dairy wastewater treatment system

technical field

The present application relates to the technical field of sewage treatment, in particular to a treatment system for dairy wastewater.

Background technique

Dairy wastewater is wastewater discharged from the production of condensed milk, cheese, cream, dairy soft drinks, ice cream, and dairy snacks. Wastewater mainly comes from the cleaning water of containers and equipment, and its main components contain raw materials for products.

Among them, cheese and butter processing wastewater have a high degree of pollution, with COD _Cr up to 3000mg/L, BOD ₅ up to 2000mg/L, total nitrogen up to 90mg/L, total phosphorus up to 16mg/L, oil up to 200mg/L, and suspended solids up to 600mg /L, therefore, the treatment of dairy wastewater is particularly difficult.

CN 217418471 U discloses a sewage treatment system, wherein the sewage treatment device includes: a pretreatment device, a biochemical reaction device, and a follow-up sludge treatment device. Among them: pretreatment device: the sewage is treated in turn through the coarse screen and the lifting pump station, the fine screen and the aeration desilting tank, and then goes to the constant water level SBR biochemical tank for biochemical reaction. Biochemical reaction stage device: The sewage reacted in the constant water level SBR biochemical tank passes through the mixed reaction sedimentation tank, filter tank, contact disinfection tank, Pasteur metering tank, and then discharges the treated water to the outside through the effluent lift pump; subsequent sludge treatment device: sewage The sludge pump in the mud pump room discharges the sludge after passing through the mixed reaction sedimentation tank and the constant water level SBR biochemical tank into the sludge storage tank, and then discharges the sludge in the sludge storage tank to the sludge thickening machine room and homogenization tank in sequence , After the sludge dehydration machine room, it is made into mud cake and sent out. However, this treatment system cannot treat dairy wastewater well, and its treatment effect is not good.

Contents of the invention

The present application provides a treatment system for dairy wastewater, which can effectively treat dairy wastewater with better treatment effect.

In the first aspect, the application provides a treatment system for dairy wastewater, including a pretreatment unit, a biochemical treatment unit and an advanced treatment unit arranged in sequence;

The pretreatment unit is used to remove impurities in dairy wastewater;

The biochemical treatment unit includes anaerobic reactors, multi-stage biological pools and secondary sedimentation tanks arranged in sequence. The multi-stage biological pools include pre-anoxic areas, anaerobic areas, anoxic first areas, aerobic first areas, and degassing areas. Zone 1, anoxic zone 2, aerobic zone 2 and degassing zone 2, the pre-anoxic zone is located at the back end of the anaerobic reactor, and the secondary settling tank is located at the back end of the degassing zone 2;

The advanced treatment unit is used to treat the total phosphorus and SS in the wastewater after the secondary sedimentation tank.

In one embodiment of the present application, the anaerobic zone, the anoxic zone 1, the degassing zone 1, the anoxic zone 2 and the degassing zone 2 are all provided with stirring devices; the aerobic zone 1 and the anoxic zone 2 are all provided with There is an aeration device.

In one embodiment of the present application, both the first degassing zone and the second degassing zone are provided with return pumps, so that part of the waste water passing through the second degassing zone can be returned to the first degassing zone.

In one embodiment of the present application, the biochemical treatment unit further includes a sludge return well for returning part of the sludge discharged from the secondary settling tank to the pre-anoxic zone.

In one embodiment of the present application, the processing system meets at least one of the following conditions:

a) The pretreatment unit is included for raising the wastewater into the anaerobic reactor;

b) The advanced treatment unit includes a magnetic coagulation sedimentation tank, a sand filter tank, a contact disinfection tank and a metering tank arranged in sequence. The magnetic coagulation sedimentation tank is located at the back end of the secondary sedimentation tank and is used to remove total phosphorus in the wastewater; the sand filter The tank is used to remove SS in the wastewater; the metering tank is equipped with metering facilities for detecting the composition of the treated wastewater;

c) The treatment system also includes a sludge treatment unit, including sludge storage tanks, sludge pump rooms, sludge thickening equipment and sludge dewatering equipment arranged in sequence. The sludge storage tanks are used to collect anaerobic reactors, multi-stage biological The remaining sludge discharged from the tank and the secondary sedimentation tank;

d) The treatment system also includes a deodorization treatment unit, which is used to collect the odor generated in the coarse grid, fine grid, anaerobic zone, anoxic zone 1, anoxic zone 2, sludge storage tank and sludge dewatering equipment ;

e) The treatment system also includes a biogas utilization unit for collecting the biogas produced by the anaerobic reactor;

f) The treatment system also includes an auxiliary unit, the auxiliary unit includes blast equipment and dosing equipment, the blast equipment is used to provide oxygen to the aerobic zone 1 and aerobic zone 2; the dosing equipment is used to add oxygen to the magnetic coagulation sedimentation tank PAC, PAM agents, and for adding sodium hypochlorite to contact disinfection tanks.

In the second aspect, the present application provides a treatment method for dairy wastewater, which is applicable to the treatment system of any one of the first aspect, and the treatment method includes:

Pass the dairy wastewater into the pretreatment unit to remove impurities in the dairy wastewater; among them, the dairy wastewater COD _Cr is 500-5000mg/L, BOD ₅ is 200-2000mg/L, ammonia nitrogen is 30-150mg/L, and the total nitrogen is 50-200mg/L, total phosphorus 5-30mg/L, SS 10-500mg/L, pH 3-10;

Then pass into anaerobic reactor, pre-anoxic zone, anaerobic zone, anoxic zone 1, aerobic zone 1, degassing zone 1, anoxic zone 2, aerobic zone 2, degassing zone 2 and secondary sedimentation Among them, the dairy wastewater stays in the anaerobic reactor for 12-24 hours, so that the COD _Cr in the dairy wastewater can be reduced by 80-90%, the BOD ₅ can be reduced by 70-80%, and the SS can be reduced by 30-50%; Stay in anoxic zone, anaerobic zone, anoxic zone 1, aerobic zone 1, degassing zone 1, anoxic zone 2, aerobic zone 2 and degassing zone 2 for a total of 15-30 hours for use in anaerobic zone The release reaction of microorganisms to phosphorus, denitrification and denitrification reaction in anoxic zone 1 and anoxic zone 2, nitrification reaction in aerobic zone 1 and aerobic zone 2, degassing zone 1 and degassing zone 2 Elimination of dissolved oxygen; then sedimentation in the secondary sedimentation tank, the sedimentation load is 0.8-1.2m ³ /m ² ·h;

Then it is passed into the advanced treatment unit to remove the total phosphorus and SS in the wastewater, so that the COD _Cr of the effluent <30mg/L, BOD ₅ <6mg/L, ammonia nitrogen <2.5mg/L, total nitrogen <15mg/L, and the total Phosphorus<0.3mg/L, SS<5mg/L, pH 6-9.

In one embodiment of the present application, part of the waste water in the second degassing zone is returned to the first degassing zone through a reflux pump, and the reflux ratio is 200-400%; the sludge discharged from the secondary sedimentation tank is discharged through the sludge return well Backflow to the pre-anoxic zone, the backflow ratio is 50-100%.

In one embodiment of the present application, the excess sludge discharged from the anaerobic reactor, multi-stage biological tank and secondary sedimentation tank is collected by the sludge treatment unit, so that the sludge concentration in the multi-stage biological tank is controlled at 4000-6000mg /L between.

In one embodiment of the present application, the wastewater discharged from the secondary sedimentation tank passes through the magnetic coagulation sedimentation tank, sand filter tank, contact disinfection tank and metering tank of the advanced treatment unit in sequence, and PAC and PAM agents are added to the magnetic coagulation sedimentation tank , and set up a mixer for mixing and stirring, and the sedimentation load of the magnetic coagulation sedimentation tank is 15-20m ³ /m ² ·h; the filtration speed of the sand filter is 6-9m ³ /h, and the residence time of the contact disinfection tank is 20 ~60min.

In one embodiment of the present application, the gas-water ratio of the first aerobic zone and the second aerobic zone is 4-10:1.

The beneficial effect of this application is:

(1) The pretreatment unit in the treatment system provided by the application can first remove most of the floating matter, grease, sand and gravel in the dairy wastewater; The multi-stage biological pool includes pre-anoxic zone, anaerobic zone, anoxic zone 1, aerobic zone 1, degassing zone 1, anoxic zone 2, aerobic zone 2 and degassing zone 2, and pre-anoxic zone The area is located at the back end of the anaerobic reactor, and the secondary settling tank is located at the back end of the second degassing area. Through the biochemical treatment unit set up in conjunction with this, most of the COD _Cr , BOD ₅ , ammonia nitrogen, total nitrogen, and The total phosphorus is SS, etc.; then continue to process part of the total phosphorus and SS in the dairy wastewater through the advanced treatment unit, so that the effluent water quality can reach the standard stably and meet the reuse water standard, which can be reused for landscaping, road watering, and river water replenishment , Replenishment of circulating cooling water in industrial enterprises, etc., can realize the utilization of sewage resources.

(2) Based on the above-mentioned treatment system, the treatment method of the present application can reduce COD _Cr by 80-90%, BOD ₅ by 70-80%, and SS by 30-80% in the anaerobic reactor after removing most of the impurities. 50%, and then reduce the amount of total phosphorus, ammonia nitrogen and total nitrogen in the multi-level biological pool, and through the cooperation of advanced treatment units, the effluent COD _Cr <30mg/L, BOD ₅ <6mg/L, ammonia nitrogen <2.5mg/L , total nitrogen<15mg/L, total phosphorus<0.3mg/L, SS<5mg/L, pH 6-9, so that the effluent water quality can reach the standard stably, meet the standard of reuse water, and can be reused for landscaping, Watering of roads, replenishment of rivers, replenishment of circulating cooling water in industrial enterprises, etc., can realize the utilization of sewage resources.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings that are required in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and thus It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Fig. 1 is a process flow diagram of a dairy wastewater treatment system provided in an embodiment of the present application.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of this application, not all of them. The components of the embodiments of the application generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations.

Accordingly, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the application. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

It should be noted that like numerals and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

In the description of the embodiments of the present application, it should be noted that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship that is usually placed when the product of the application is used, or the orientation or positional relationship of this application. The orientation or positional relationship commonly understood by those skilled in the art, or the orientation or positional relationship that is usually placed when the application product is used, is only for the convenience of describing the application and simplifying the description, rather than indicating or implying that the referred device or element must be Having a particular orientation, being constructed and operating in a particular orientation, and therefore not to be construed as limiting the application. In addition, the terms "first", "second", etc. are only used for distinguishing descriptions, and should not be construed as indicating or implying relative importance.

In the description of the embodiments of this application, it should also be noted that, unless otherwise specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or It is a detachable connection or an integral connection; it can be directly connected or indirectly connected through an intermediary. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application in specific situations.

The dairy wastewater treated by this application has COD _Cr of 500-5000mg/L, BOD ₅ of 200-2000mg/L, ammonia nitrogen of 30-150mg/L, total nitrogen of 50-200mg/L, and total phosphorus of 5-30mg/L. SS is 10-500 mg/L, and pH is 3-10.

Fig. 1 is a process flow diagram of a dairy wastewater treatment system provided in an embodiment of the present application. Referring to Figure 1, the treatment system includes a pretreatment unit, a biochemical treatment unit and an advanced treatment unit arranged in sequence; and a sludge treatment unit, a deodorization treatment unit, a biogas utilization unit and an auxiliary unit.

Among them, the pretreatment unit includes a coarse grid, a lifting pool and a pump station, a fine grid, an oil separation grit chamber and a regulating tank arranged in sequence, and a lifting pump set is arranged at the end of the regulating tank.

The corresponding pretreatment method is: the dairy wastewater is collected through the pipe network and then gravity flows into the coarse grid. The coarse grid adopts a rotary coarse grid with a filtration accuracy of 15mm, which can intercept large floating objects and sundries; Stay in the pool for 30 minutes, and a submersible lift pump is installed in the lifting pool to lift the dairy wastewater to a fine grid. The fine grid adopts a stepped orifice type fine grid with a filtration accuracy of 3mm; The residence time of the oil grit chamber is 5 minutes to separate the oil and sand in the waste water; the gravity flow of the effluent from the oil separation grit chamber enters the adjustment tank with a residence time of 8 to 12 hours to homogenize and adjust the water volume of the dairy wastewater. There is a stirring device in the adjustment tank to prevent sedimentation, and a lifting pump group is installed at the end of the adjustment tank. The pretreatment unit mainly removes floating matter, oil, sand and other impurities in dairy wastewater.

The biochemical treatment unit includes anaerobic reactors, multi-stage biological pools and secondary sedimentation tanks arranged in sequence. The multi-stage biological pools include pre-anoxic areas, anaerobic areas, anoxic first areas, aerobic first areas, and degassing areas. The first zone, the second anoxic zone, the second aerobic zone and the second degassing zone, the pre-anoxic zone is located at the back end of the anaerobic reactor, and the secondary sedimentation tank is located at the back end of the degassing zone two.

The corresponding biochemical treatment method is: the lifting pump set lifts the wastewater into the anaerobic reactor, and the anaerobic reactor adopts an upflow anaerobic sludge bed reactor with a residence time of 12 to 24 hours; the dairy wastewater undergoes anaerobic reaction. After treatment, the COD _Cr is reduced by 80-90%, the BOD ₅ is reduced by 70-80%, and the SS is reduced by 30-50%. The effluent of the anaerobic reactor enters the multi-stage biological pool, and the dairy wastewater enters the pre-anoxic zone, anaerobic zone, anoxic zone 1, aerobic zone 1, degassing zone 1, anoxic zone 2, aerobic zone 2, The degassing zone 2, and then enter the secondary sedimentation tank for mud-water separation; the residence time of the multi-stage biological pool is 15-30h, in the anoxic zone 1 and anoxic zone 2, anaerobic zone 1 and anaerobic zone 2, and degassing zone 1 and degassing zone 2 are equipped with stirring devices, aeration devices are set in aerobic zone 1 and aerobic zone 2, and denitrification and denitrification reactions are realized in anoxic zone 1 and anoxic zone 2 (nitrate nitrogen and nitrite nitrogen in Under the action of denitrifying bacteria, it is reduced to nitrogen), the release reaction of microorganisms to phosphorus is realized in the anaerobic zone 1 and anaerobic zone 2, and the nitrification reaction is realized in the aerobic zone 1 and aerobic zone 2 (ammonia nitrogen is first converted to sub Nitrate nitrogen, nitrite nitrogen is converted into nitrate nitrogen) and the absorption reaction of microorganisms to phosphorus, and the dissolved oxygen in the water is eliminated in the degassing zone 1 and degassing zone 2. Among them, the degassing zone 1 and the degassing zone 2 are equipped with internal return pumps, which adopt the form of through-wall pumps, so that part of the wastewater passing through the degassing zone 2 can be returned to the degassing zone 1, and the reflux ratio is 200-400%. An outlet weir is installed at the end of the second gas zone to control the liquid level in the multi-stage biological pool. The sludge concentration in the multi-stage biological pool is controlled at 4000-6000mg/L; A circular secondary settling tank is adopted, with a sedimentation load of 0.8-1.2m ³ /m ² h, and the sludge from the secondary settling tank is discharged into the sludge return well, which is used to return part of the sludge discharged from the secondary settling tank to In the pre-anoxic zone, the reflux ratio is 50-100%, and the remaining sludge is discharged into the sludge storage tank of the sludge treatment unit. The biochemical treatment unit mainly removes most of COD _Cr , BOD ₅ , ammonia nitrogen, total nitrogen, total phosphorus, SS, etc. in dairy wastewater.

The advanced treatment unit includes a magnetic coagulation sedimentation tank, a sand filter tank, a contact disinfection tank and a metering tank arranged in sequence, and the magnetic coagulation sedimentation tank is located at the rear end of the secondary sedimentation tank.

The corresponding advanced treatment method is: the effluent of the secondary sedimentation tank enters the magnetic coagulation sedimentation tank, PAC and PAM agents are added at the water inlet, and a mixer is installed for mixing and stirring. The sedimentation load of the magnetic coagulation sedimentation tank is 15-20m ³ /m ² ·h, mainly removes total phosphorus in dairy wastewater, so that the total phosphorus in the effluent is less than 0.3mg/L; the effluent from the magnetic coagulation sedimentation tank enters the sand filter, and the sand filter adopts the form of a downflow filter. Natural quartz sand is used, and the filtration speed is 6-9m/h. It mainly removes SS in the wastewater, so that the effluent SS is less than 5mg/L; the sand filter is equipped with backwashing equipment, and adopts the working mode of air washing-air washing-water washing; The effluent from the sand filter flows into the contact disinfection tank by gravity, and the residence time is 20-60 minutes, adding sodium hypochlorite solution for disinfection; the effluent from the contact disinfection tank passes through the metering facilities in the metering tank to test the quality of the effluent water, so as to confirm that it can meet the discharge standards and reuse. Among them, the metering facility adopts a bus metering tank or an electromagnetic flowmeter. The advanced treatment unit mainly removes total phosphorus and SS in dairy wastewater. After the advanced treatment unit, the effluent COD _Cr <30mg/L, BOD ₅ <6mg/L, ammonia nitrogen <2.5mg/L, total nitrogen <15mg/L, total phosphorus <0.3mg/L, SS<5mg/L, The pH is 6-9.

In this application, the sludge treatment unit includes sludge storage tanks, sludge pump rooms, sludge thickening equipment and sludge dewatering equipment arranged in sequence. The sludge storage tanks are used to collect anaerobic reactors, multi-stage biological pools and secondary The remaining sludge discharged from the settling tank controls the sludge concentration in the multi-stage biological tank between 4000 and 6000mg/L. Sludge dehydration equipment can be used to dehydrate the sludge to make the moisture content of the sludge <60%, so that the sludge can be used for land greening, garden construction, soil improvement, etc.

In this application, the deodorization treatment unit is used to collect the odor produced in the coarse grid, fine grid, anaerobic zone, anoxic zone 1, anoxic zone 2, sludge storage tank and sludge dehydration equipment; The deodorization technology is used for treatment, and finally discharges up to the standard.

In this application, the biogas utilization unit is used to collect the biogas produced by the anaerobic reactor; it is stored in the biogas tank, and can be used in the biogas boiler after purification.

In the present application, the auxiliary unit includes air blowing equipment and dosing equipment, and the air blowing equipment is used to provide oxygen to the aerobic zone one and the aerobic zone two, so that the gas-water ratio of the aerobic zone one and the aerobic zone two is 4~ 10:1; Dosing equipment is used to add PAC and PAM agents to the magnetic coagulation sedimentation tank, and to add sodium hypochlorite to the contact disinfection tank.

Among them, the deodorization processing unit, the biogas utilization unit and the auxiliary unit are all existing processing units, which will not be described in detail here, mainly because their installation positions are different.

Through the treatment system and treatment method to treat dairy wastewater, the following effects can be achieved:

(1) The dairy wastewater treatment method has high impact resistance, the effluent quality can reach the standard stably, and can meet the reuse water standard. It can be reused for landscaping, road watering, river water replenishment, and industrial enterprise circulating cooling water replenishment, etc., which can realize Utilization of sewage resources.

(2) The dairy wastewater treatment method does not require the addition of carbon sources, the chemical consumption is small, and the operating cost is low.

(3) The biogas produced by the system fully utilized by the dairy wastewater treatment method can be used in biogas boilers after purification, which saves energy and reduces carbon emissions.

(4) The dairy wastewater treatment method is environmentally friendly. After the odor generated by the system is collected, it is treated with biological deodorization technology, and finally discharged up to the standard without odor overflow.

(5) The sludge produced by the dairy wastewater treatment method can be used for land afforestation, garden construction, soil improvement, etc. after dehydration treatment (moisture content <60%), and can realize the resource utilization of sludge.

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.

Example 1

The sewage is mainly the dairy wastewater of Mengniu Company. The dairy wastewater is collected through the pipe network and then flows into the rotary coarse grid by gravity, with a filtration accuracy of 15mm. Then it enters the lifting pool and stays for 30 minutes. The dairy wastewater is lifted to the stepped hole by the submersible lifting pump. The plate-type fine screen has a filtration accuracy of 3mm; then the gravity flow enters the oil-separating grit chamber and stays for 5 minutes; the gravity flow of the effluent from the oil-separating grit chamber enters the regulating tank equipped with a stirring device and stays for 10 hours.

Lift the wastewater into the anaerobic reactor through the lifting pump group at the end of the regulating tank, and stay in the upflow anaerobic sludge bed reactor for 20 hours; the effluent from the anaerobic reactor enters the multi-stage biological pool and enters the pre-anoxic zone in turn , anaerobic zone, anoxic zone 1, aerobic zone 1, degassing zone 1, anoxic zone 2, aerobic zone 2, degassing zone 2, and then enter the secondary sedimentation tank for mud-water separation; the residence time of the multi-stage biological tank For 25 hours, set stirring devices in anoxic zone 1 and anoxic zone 2, anaerobic zone 1 and anaerobic zone 2, degassing zone 1 and degassing zone 2, and set aeration in aerobic zone 1 and aerobic zone 2 The device, wherein, the degassing zone 1 and the degassing zone 2 are equipped with through-wall reflux pumps so that part of the waste water passing through the degassing zone 2 can be returned to the degassing zone 1, and the reflux ratio is 300%; the end of the degassing zone 2 is set There is an outlet weir to control the liquid level in the multi-stage biological pool. The sludge concentration in the multi-stage biological pool is controlled at 4000-6000mg/L; 1.0m ³ /m ² ·h, the sludge from the secondary settling tank is discharged into the sludge return well, which is used to return part of the sludge discharged from the secondary settling tank to the pre-anoxic zone, the return ratio is 80%, and the remaining sludge is discharged into the sludge storage tank of the sludge treatment unit.

The effluent of the secondary sedimentation tank enters the magnetic coagulation sedimentation tank, and PAC and PAM chemicals are added at the water inlet, and a mixer is installed for mixing and stirring. The sedimentation load of the magnetic coagulation sedimentation tank is 18m ³ /m ² ·h; the magnetic coagulation The effluent from the sedimentation tank enters the downflow filter, the filter material is natural quartz sand, and the filtration speed is 8m/h; Gravity flows into the contact disinfection tank and stays for 30 minutes, adding sodium hypochlorite solution for disinfection; the effluent from the contact disinfection tank passes through the metering facilities in the metering tank to test the quality of the effluent.

The test results are shown in Table 1.

Table 1 Test inlet and outlet water quality data

It can be seen from Table 1 that the method provided by this application has a good effect on the treatment of dairy wastewater and can be directly discharged up to the standard.

Comparative example 1

The sewage is mainly the dairy wastewater of Mengniu Company. The dairy wastewater is collected through the pipe network and then flows into the rotary coarse grid by gravity, with a filtration accuracy of 15mm. Then it enters the lifting pool and stays for 30 minutes. The dairy wastewater is lifted to the stepped hole by the submersible lifting pump. The plate-type fine screen has a filtration accuracy of 3mm; then the gravity flow enters the oil-separating grit chamber and stays for 5 minutes; the gravity flow of the effluent from the oil-separating grit chamber enters the regulating tank equipped with a stirring device and stays for 10 hours.

Lift the wastewater into the SBR biochemical tank through the lifting pump group at the end of the regulating tank for 45 hours of aeration. Then enter the magnetic coagulation sedimentation tank, add PAC and PAM chemicals at the water inlet, and set up a stirrer for mixing and stirring. The sedimentation load of the magnetic coagulation sedimentation tank is 18m ³ /m ² ·h; the effluent of the magnetic coagulation sedimentation tank Entering the downflow filter, the filter material is natural quartz sand, and the filtration speed is 8m/h; the sand filter is equipped with backwashing equipment, which adopts the working mode of air washing-air water washing-water washing; the effluent of the sand filter flows into the contact disinfection by gravity Stay in the pool for 30 minutes, then add sodium hypochlorite solution for disinfection; the effluent from the disinfection pool passes through the metering facilities in the metering tank to test the quality of the effluent.

The test results are shown in Table 2.

Table 2 Test inlet and outlet water quality data

It can be seen from Table 2 that the method provided in Comparative Example 1 has a poor treatment effect on dairy wastewater, and some indicators can reach the first-level A standard of the national standard, but the ammonia nitrogen and total nitrogen indicators cannot meet the standards.

The above are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, there may be various modifications and changes in the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims (5)

1. The system for treating the milk industry wastewater is characterized by comprising a pretreatment unit, a biochemical treatment unit and a deep treatment unit which are sequentially arranged;

the pretreatment unit is used for removing impurities in the dairy wastewater;

the biochemical treatment unit comprises an anaerobic reactor, a multi-stage biological pond and a secondary sedimentation pond which are sequentially arranged, wherein the multi-stage biological pond comprises a pre-anoxic zone, an anaerobic zone, an anoxic zone, an aerobic zone, a degassing zone, an anoxic zone, an aerobic zone and a degassing zone which are sequentially arranged, the pre-anoxic zone is positioned at the rear end of the anaerobic reactor, and the secondary sedimentation pond is positioned at the rear end of the degassing zone;

the advanced treatment unit is used for treating total phosphorus and SS in the wastewater after passing through the secondary sedimentation tank.

2. The treatment system of claim 1, wherein the anaerobic zone, the anoxic first zone, the degassing first zone, the anoxic second zone, and the degassing second zone are each provided with a stirring device; and the aerobic first zone and the anoxic second zone are both provided with aeration devices.

3. The treatment system of claim 1, wherein both the first and second regions are provided with a return pump to return a portion of the wastewater passing through the second region to the first region.

4. A treatment system according to claim 3, wherein the biochemical treatment unit further comprises a sludge recirculation well for recirculating a portion of the sludge discharged from the secondary sedimentation tank to the pre-anoxic zone.

5. The processing system of any of claims 1-4, wherein the processing system meets at least one of the following conditions:

a) The pretreatment unit comprises a coarse grating, a lifting water tank, a pump station, a fine grating, an oil separation sand setting tank and an adjusting tank which are sequentially arranged, wherein the tail end of the adjusting tank is provided with a lifting pump set for lifting the wastewater into the anaerobic reactor;

b) The advanced treatment unit comprises a magnetic coagulation sedimentation tank, a sand filter tank, a contact disinfection tank and a metering tank which are sequentially arranged, wherein the magnetic coagulation sedimentation tank is positioned at the rear end of the secondary sedimentation tank and is used for removing total phosphorus in the wastewater; the sand filter is used for removing SS in the wastewater; a metering facility is arranged in the metering tank and is used for detecting the components of the treated wastewater;

c) The treatment system further comprises a sludge treatment unit, and the sludge treatment unit comprises a sludge storage pool, a sludge pump house, sludge concentration equipment and sludge dewatering equipment which are sequentially arranged, wherein the sludge storage pool is used for collecting residual sludge discharged by the anaerobic reactor, the multistage biological pool and the secondary sedimentation tank;

d) The treatment system further comprises a deodorizing treatment unit for collecting odor generated in the coarse grille, the fine grille, the anaerobic zone, the anoxic first zone, the anoxic second zone, the sludge storage tank and the sludge dewatering equipment;

e) The treatment system further comprises a biogas utilization unit for collecting biogas generated by the anaerobic reactor;

f) The treatment system further comprises an auxiliary unit, wherein the auxiliary unit comprises a blower device and a dosing device, and the blower device is used for providing oxygen for the first aerobic zone and the second aerobic zone; the dosing equipment is used for adding PAC and PAM medicaments into the magnetic coagulation sedimentation tank and adding sodium hypochlorite into the contact disinfection tank.

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