A sewage pretreatment carbon source rapid separation device and sewage treatment method

Abstract

The present invention relates to the technical field of sewage treatment, and in particular to a sewage pretreatment carbon source rapid separation device and a sewage treatment method, the method comprising: S1, mixing sewage with a flocculant for preliminary mixing to obtain a first mixture; S2, introducing the first mixture into a sedimentation tank for mixed sedimentation, setting a mixing zone filled with VF filler and a sedimentation zone for introducing micro sand from top to bottom in the sedimentation tank, and performing gas lift mixing from bottom to top at the bottom of the sedimentation tank; obtaining clean water and mud and sand sediment; S3, performing mud and sand separation on the mud and sand sediment to obtain micro sand and sludge; S4, recycling the micro sand for introduction into the sedimentation zone in S2; S5, concentrating and separating the sludge. The present invention can greatly shorten the sedimentation time and improve the treatment effect; wherein the micro sand can accelerate the flocculation and agglomeration, increase the volume of floc particles, shorten the residence time of the sedimentation tank, realize rapid solid-liquid separation, and thus realize a large amount of continuous water discharge.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, in particular to a sewage pretreatment carbon source rapid separation device and a sewage treatment method. Background Art

[0002] The wastewater generated by large-scale farms is mainly high-concentration, high-ammonia nitrogen, high-suspended solids, and difficult to treat "three highs" wastewater. The characteristics of large quantity, relative concentration, and difficulty in treatment lead to many problems in the treatment process. The use of pretreatment methods can reduce the load of wastewater pollutants in subsequent treatment steps, while preventing large solids or debris from entering the subsequent treatment links, causing congestion or damage to the treatment equipment. Therefore, appropriate pretreatment is required before biochemical treatment to reduce the subsequent load.

[0003] However, the traditional pretreatment sedimentation separation process technology in the prior art has the disadvantages of large footprint, long residence time, long process flow and poor separation effect. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a sewage pretreatment carbon source rapid separation device and a sewage treatment method, which solves the disadvantages of the traditional sedimentation separation process technology in the prior art, such as large footprint, long residence time, long process flow, poor separation effect, etc. The present invention is suitable for municipal sewage and other sewage, and adopts a flocculant combined with micro-sand and VF filler and air lift mixing method to quickly precipitate and separate suspended matter and colloids with high carbon sources; and the micro-sand can be separated and recycled.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] In a first aspect, a device for rapid separation of carbon sources for sewage pretreatment is provided, comprising:

[0007] The sedimentation tank has a water inlet and a water outlet at the top and a sewage outlet at the bottom. The interior of the tank is divided into a mixing zone and a sedimentation zone from top to bottom. An air lift mechanism is installed at the bottom of the sedimentation zone, and a sand inlet is provided on the side of the sedimentation zone.

[0008] VF filler, which is filled in the mixing zone and has a plurality of pores inside;

[0009] Flocculant inlet pipe;

[0010] A water inlet pipe, which is connected to the water inlet and is used to feed sewage into the sedimentation tank; and an opening is provided on the side of the water inlet pipe and the opening is connected to the flocculant inlet pipe;

[0011] A micro-sand inlet pipe, which is connected to the sand inlet and is used to feed micro-sand into the sedimentation area;

[0012] A water outlet pipe, one end of which is a water outlet end, and the other end is a closed end, and the closed end passes through the water outlet and extends into the sedimentation tank and is located above the mixing zone. The top of the side of the water outlet pipe is provided with drainage ports arranged at intervals along its axial direction, so that water from above the mixing zone enters the water outlet pipe through the drainage ports and is discharged;

[0013] A mud-sand separator, which has an inlet, a mud outlet, and a micro-sand outlet, wherein the inlet is connected to the sewage outlet of the sedimentation tank through an air lift pipe;

[0014] A concentrating mechanism is communicated with the sludge outlet of the mud-sand separator.

[0015] Preferably, the fine sand outlet of the mud-sand separator is connected to the fine sand inlet pipe through a reflux pipe.

[0016] Preferably, the sludge outlet of the concentrating mechanism is connected to a subsequent dehydration mechanism.

[0017] Preferably, the VF filler has a spiral pore structure or a honeycomb structure.

[0018] It is understood that the air stripping mechanism is a flat aeration pipe arranged at the bottom of the sedimentation zone. It is understood that the top of the VF filler is close to the bottom of the water outlet pipe.

[0019] In a second aspect, a sewage treatment method is provided, which is carried out in the sewage pretreatment carbon source rapid separation device described in the first aspect and comprises the following steps:

[0020] S1, preliminarily mixing the sewage and the flocculant to obtain a first mixture;

[0021] S2, introducing the first mixture into a sedimentation tank for mixed sedimentation, wherein a mixing zone filled with VF filler and a sedimentation zone for introducing micro-sand are arranged from top to bottom in the sedimentation tank, and air stripping and mixing are performed from bottom to top at the bottom of the sedimentation tank; and clean water and mud and sand sediments are obtained in the upper and lower parts of the sedimentation tank respectively through the mixed sedimentation;

[0022] S3, separating the mud and sand sediment into fine sand and sludge;

[0023] S4, circulating the micro sand in S2 and introducing it into the sedimentation zone;

[0024] S5, concentrating and separating the sludge.

[0025] Preferably, in S1, the amount of the flocculant used is 100-2000 mg / L, preferably 1500-1800 mg / L, based on the mass of ferric sulfate, relative to the sewage. This preferred solution can accelerate the destabilization of pollutants and is more conducive to the subsequent adsorption of pollutants to form flocs. More preferably, the flocculant is

[0026] Preferably, in S1, the flocculant is an iron salt or an organic flocculant or a composite flocculant.

[0027] The iron salt is preferably polyferric chloride (PFC) and polyferric sulfate (PFS). The organic flocculant is preferably polyacrylamide (PAM). The composite flocculant is a combination of polyaluminium chloride and polyferric sulfate.

[0028] Preferably, the flocculant is polyferric chloride, polyferric sulfate, polyacrylamide, or a combination of polyaluminium chloride and polyferric sulfate.

[0029] Preferably, in S2, the filling height of the VF filler is 0.6-2.7 m. This preferred solution enables a large amount of water to enter the mixing zone and then be fully and quickly mixed and flocculated in the VF filler, which is more conducive to the adsorption and precipitation of pollutants.

[0030] Preferably, in S2, the amount of microsand added is determined according to the amount of flocs produced by a small-dose flocculation experiment, as long as the suspended solids and colloids of the high carbon source can be quickly precipitated and separated.

[0031] It can be understood that in the sedimentation zone, the micro-sand precipitates and separates the suspended matter and colloid of the high carbon source to form floccules. The floccules and micro-sand will not enter the VF filler area and will be retained by the VF filler.

[0032] In the present invention, sewage enters the mixing zone and forms vortexes in the mixing zone and the sedimentation zone through air lift aeration, which not only promotes mixing and flocculation in the VF filler area, but also promotes mixing of pollutant flocs and micro-sand in the sedimentation zone, thereby accelerating sedimentation.

[0033] Preferably, the method further includes: S6, directly feeding the concentrated sludge obtained in S5 into a subsequent dehydration step.

[0034] The beneficial effects of the above technical solution of the present invention are as follows:

[0035] In the above scheme, the sewage is first subjected to preliminary flocculation treatment using a flocculant, and the suspended and particulate matter therein is pre-filtered to remove, and then a mixing zone and a sedimentation zone are specially set up from top to bottom, and a porous filler is set in the mixing zone to enable hydraulic mixing, which not only evens out the hydraulic distribution, but also causes the water flow to continuously change direction due to the momentum during the rising process. The activated sludge will be intercepted due to the effect of inertia, and the solid-liquid separation efficiency of the activated sludge is further improved. The present invention solves the problem that a large amount of water is difficult to mix, and can make the flocculant and micro-sand mix efficiently and quickly during the mixing process. Under the separation effect of the filler, and with the air lift mixing and mixing assistance of the air lift mechanism, the sedimentation time can be greatly shortened and the treatment effect can be improved; wherein the micro-sand can accelerate the flocculation and agglomeration, increase the volume of the floc particles, shorten the residence time of the sedimentation tank, and achieve rapid solid-liquid separation, thereby achieving a large amount of continuous water discharge. In the preferred scheme, the micro-sand can be recycled and reused, which increases the economic benefit.

[0036] The treatment method of the present invention organically combines flocculation, micro-sand, VF filler and air lift, can perform rapid and efficient mixing, greatly shorten the sedimentation time, improve the treatment effect; and can achieve continuous discharge of purified water. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of the present invention.

[0038] Figure 2 A schematic diagram of the structure of the filler.

[0039] [reference numerals]

[0040] 1. Sedimentation tank, 11. Mixing zone, 12. Sedimentation zone, 2. Water inlet pipe, 3. Flocculant inlet pipe, 4. Micro sand inlet pipe, 5. Air lift mechanism, 6. Water outlet pipe, 61. Drain, 7. Mud and sand separator, 8. Concentration mechanism. DETAILED DESCRIPTION

[0041] like Figure 1 As shown, the present invention provides a sewage pretreatment carbon source rapid separation device, comprising:

[0042] The sedimentation tank 1 has a water inlet and a water outlet at the top and a sewage outlet at the bottom. The interior of the sedimentation tank 1 is composed of a mixing zone 11 and a sedimentation zone 12 from top to bottom. An air lift mechanism 5 is installed at the bottom of the sedimentation zone 12. A sand inlet is provided on the side of the sedimentation zone 12.

[0043] A filler, which is filled in the mixing zone 11 and has a plurality of pores inside;

[0044] Flocculant inlet pipe 3;

[0045] A water inlet pipe 2, which is connected to the water inlet and is used to feed sewage into the sedimentation tank 1; and an opening is provided on the side of the water inlet pipe 2 and the opening is connected to the flocculant inlet pipe 3;

[0046] The micro-sand inlet pipe 4 is connected to the sand inlet and is used to feed micro-sand into the sedimentation area 12 .

[0047] When used, sewage enters the sedimentation tank 1 from the water inlet pipe 2, and is mixed with the flocculant in the flocculant inlet pipe 3 for preliminary flocculation treatment before entering, and then is deeply mixed in the filler in the mixing area 11 of the sedimentation tank 1. The pores in the filler make the hydraulic distribution and hydraulic mixing uniform, which promotes the treatment effect; then it enters the sedimentation area 12 and is mixed with micro sand for air lift, which accelerates the floc agglomeration and sedimentation, and shortens the residence time of the sedimentation tank. It can be understood that when used, the material will submerge the filler, and the water level will not be lower than the height of the filler.

[0048] The sewage in the present invention can be COD sewage, and the present invention is more suitable for the treatment of COD sewage. In the sewage treatment process, the sewage granular COD and colloidal COD are separated by flocculants and micro-sands to flocculate and precipitate, and at the same time, part of the soluble COD is adsorbed into the activated sludge flocs, separated by precipitation, and a large amount of water that meets the standards is obtained.

[0049] Preferably, it also includes:

[0050] The outlet pipe 6 has one end as the outlet end and the other end as a closed end. The closed end passes through the outlet port and extends into the sedimentation tank 1 and is located above the mixing zone 11. The top of the side of the outlet pipe 6 is provided with drain ports 61 spaced apart along its axial direction, so that the water from above the mixing zone 11 enters the outlet pipe 6 through the drain ports 61 and is discharged.

[0051] In the present invention, the flocculants and other high-density components in the sewage sink in the sedimentation tank 1, and the water in the sewage remains above the mixing zone 11 and enters the outlet pipe 6 through the drain port to be discharged.

[0052] Preferably, it also includes:

[0053] A mud-sand separator 7, which has an inlet, a mud outlet, and a micro-sand outlet, wherein the inlet is connected to the sewage outlet of the sedimentation tank 1 through an air lift pipe;

[0054] The concentrating mechanism 8 is communicated with the sludge outlet of the mud-sand separator 7 .

[0055] More preferably, the micro-sand outlet of the mud-sand separator 7 is connected to the micro-sand inlet pipe 4 through a reflux pipe. The mud-sand separator 7 is preferably a cyclone mud-sand separator.

[0056] More preferably, the sludge outlet of the concentrating mechanism 8 is communicated with a subsequent dehydration mechanism.

[0057] The present invention adds micro-sand to accelerate floc agglomeration and sedimentation, thereby shortening the residence time in the sedimentation tank; the precipitated mixture after flocculation, mixing, sedimentation and separation of sewage is lifted to the mud and sand separator 7 by an air lift pipe for mud and sand separation, and the separated carbon-rich sludge and water are discharged out of the system, and the separated micro-sand is returned to the sedimentation area 12 for recycling and preparation for subsequent process applications.

[0058] Preferably, the filler is VF filler. This preferred solution is more conducive to adsorbing organic matter in sewage on the surface of the filler, so that the effluent continues to meet the discharge standards. VF filler is an existing product, such as the VF filler of the applicant's early patent CN106044876B, which will not be repeated here.

[0059] Preferably, the pores in the filler are distributed in multiple directions including up, down, left and right.

[0060] Preferably, the filler is a spiral pore structure or a honeycomb structure (such as Figure 2 shown).

[0061] Preferably, the bottom of the sedimentation tank 1 is conical.

[0062] The present invention solves the disadvantages of the traditional sedimentation separation process technology in the prior art, such as large footprint, long residence time, long process flow, poor separation effect, etc. The present invention can be applied to municipal sewage or other sewage, and can use iron salt flocculation or organic flocculant, combined with micro-sand for rapid precipitation and separation of suspended matter and colloids with high carbon sources.

[0063] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0064] Example 1

[0065] A sewage treatment method, wherein Figure 1 The sewage pretreatment carbon source rapid separation device shown is carried out, comprising:

[0066] S1, preliminarily mixing the sewage and the flocculant (specifically polyferric sulfate (PFS)) to obtain a first mixture;

[0067] S2, introducing the first mixture into a sedimentation tank for mixed sedimentation, wherein a mixing zone filled with VF filler and a sedimentation zone for introducing micro sand are arranged from top to bottom in the sedimentation tank, and air stripping and mixing are performed from bottom to top at the bottom of the sedimentation tank; clean water and mud and sand sediments are obtained at the upper and lower parts of the sedimentation tank respectively through the mixed sedimentation; the filling height of the VF filler is 0.6m;

[0068] S3, separating the mud and sand sediment into fine sand and sludge;

[0069] S4, circulating the micro sand in S2 and introducing it into the sedimentation zone;

[0070] S5, concentrating and separating the sludge.

[0071] The sewage in this embodiment contains COD, ammonia nitrogen, total nitrogen, SS, total phosphorus, PH, etc. When the flocculant is added at 1.5 mg / mL, larger flocs are produced, and the amount of adsorbed sand is relatively large. The micro-sand loss rate is 7.25%, and the micro-sand separation recovery rate is 92.75%.

[0072] Example 2

[0073] The method of Example 1 is referred to, except that the dosage of the flocculant is 2 mg / mL relative to the sewage.

[0074] In this embodiment, the water sample sedimentation effect and the state of the supernatant are slightly different from those in Example 1, but the amount of sand lost with the flocs during separation is large, and the loss is the largest. The micro-sand loss rate is 22.8%, and the micro-sand separation recovery rate is 77.2%.

[0075] Example 4

[0076] The method of Example 1 is referred to, except that the dosage of the flocculant is 1.3 mg / mL relative to the sewage.

[0077] In this embodiment, the amount of flocculants in the water is insufficient, resulting in small flocs, which leads to a small amount of micro-sand attached to the flocs, poor sedimentation effect, and a small amount of sand lost with the flocs during separation. The micro-sand loss rate is 2.62%, and the micro-sand separation recovery rate is 97.38%.

[0078] Comparative Example 1

[0079] The method of Example 1 is followed, except that no micro sand is introduced.

[0080] In this comparative example, the supernatant of the water sample assisted by micro-sand sedimentation is clearer, while the sedimentation speed of the water sample without adding micro-sand is slow, and the supernatant is turbid and not transparent, with a large number of fine suspended particles.

[0081] Comparative Example 2

[0082] The method of Example 1 was followed, except that no VF filler was added.

[0083] In this comparative example, the water was not mixed evenly, the mixing rate after adding the reagent was slow, and the precipitation effect was poor.

[0084] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A rapid separation device for carbon source in sewage pretreatment, characterized in that: include: The sedimentation tank has a water inlet and a water outlet at the top and a sewage outlet at the bottom. The interior of the tank is divided into a mixing zone and a sedimentation zone from top to bottom. An air lift mechanism is installed at the bottom of the sedimentation zone, and a sand inlet is provided on the side of the sedimentation zone. VF filler, which is filled in the mixing zone and has a plurality of pores inside, and the VF filler has a spiral pore structure or a honeycomb structure; Flocculant inlet pipe; A water inlet pipe, which is connected to the water inlet and is used to feed sewage into the sedimentation tank; and an opening is provided on the side of the water inlet pipe and the opening is connected to the flocculant inlet pipe; A micro-sand inlet pipe, which is connected to the sand inlet and is used to feed micro-sand into the sedimentation area; A water outlet pipe, one end of which is a water outlet end, and the other end is a closed end, and the closed end passes through the water outlet and extends into the sedimentation tank and is located above the mixing zone. The top of the side of the water outlet pipe is provided with drainage ports arranged at intervals along its axial direction, so that water from above the mixing zone enters the water outlet pipe through the drainage ports and is discharged; A mud-sand separator, which has an inlet, a mud outlet, and a micro-sand outlet, wherein the inlet is connected to the sewage outlet of the sedimentation tank through an air lift pipe; A concentrating mechanism is communicated with the sludge outlet of the mud-sand separator.

2. The device for rapid separation of carbon sources for sewage pretreatment according to claim 1, characterized in that: The micro-sand outlet of the mud-sand separator is communicated with the micro-sand inlet pipe through a reflux pipe.

3. The rapid separation device for carbon source in sewage pretreatment according to claim 1, characterized in that: The sludge outlet of the concentrating mechanism is communicated with the dehydrating mechanism.

4. A sewage treatment method, characterized in that: The method is carried out in the sewage pretreatment carbon source rapid separation device according to any one of claims 1 to 3, and comprises the following steps: S1, preliminarily mixing the sewage and the flocculant to obtain a first mixture; S2, introducing the first mixture into a sedimentation tank for mixed sedimentation, wherein a mixing zone filled with VF filler and a sedimentation zone for introducing micro sand are arranged from top to bottom in the sedimentation tank, wherein the VF filler has a spiral pore structure or a honeycomb structure, and air stripping and mixing are performed from bottom to top at the bottom of the sedimentation tank; After the mixed sedimentation, clean water and mud and sand sediment are obtained in the upper part and the lower part of the sedimentation tank respectively; S3, separating the mud and sand sediment to obtain fine sand and sludge; S4, circulating the micro sand in S2 and introducing it into the sedimentation zone; S5, concentrating and separating the sludge; Porous fillers are set in the mixing zone for hydraulic mixing, which not only makes the hydraulic distribution uniform, but also causes the water flow to constantly change direction during the rising process. The activated sludge is intercepted due to inertia, solving the problem of large amounts of water being difficult to mix.

5. The sewage treatment method according to claim 4, characterized in that: In S1, the amount of the flocculant used is 100-2000 mg / L based on the mass of ferric sulfate relative to the sewage.

6. The sewage treatment method according to claim 4, characterized in that: In S1, the flocculant is polyferric chloride, polyferric sulfate, polyacrylamide, or a combination of polyaluminium chloride and polyferric sulfate.

7. The sewage treatment method according to claim 4, characterized in that: In S2, the filling height of VF filler is 0.6-2.7m.

8. The sewage treatment method according to claim 4, characterized in that: Also includes: S6. Discharge the concentrated sludge obtained in S5 and subsequently dehydrate it.

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