CN115947431B - Method for quickly combining suspended matters in water with flocs by taking micro sand as crystallization nucleus - Google Patents

Abstract

The invention relates to the technical field of sewage treatment, in particular to a method for quickly combining suspended matters in water with flocs by taking micro sand as crystallization nucleus, which comprises the following steps: s1, introducing sewage to be treated into a water inlet pipe, and introducing a flocculating agent into an opening on the water inlet pipe; s2, introducing the obtained first mixture into a sedimentation tank for mixed sedimentation, sequentially arranging a mixing zone filled with VF filler, a sedimentation zone for introducing micro sand and the bottom of the sedimentation zone from top to bottom in the sedimentation tank, and transversely inserting a water outlet pipe above the filler in the mixing zone; and respectively obtaining purified water and silt sediment at the upper part and the lower part of the sedimentation tank. The invention uses the micro sand particles and the chemical flocculant to strengthen the flocs so as to improve the settling property of suspended matters in water; by utilizing the internal structure of the filler, not only is the hydraulic distribution uniform, but also the direction of the activated sludge is continuously changed due to potential in the water flow rising process, the activated sludge can be intercepted due to the action of inertia, and the solid-liquid separation efficiency of the activated sludge is further improved.

Description

Method for rapidly combining suspended matter in water with flocs by using micro-sand as crystal nucleus

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a method for rapidly combining suspended matter in water with flocs by using micro-sand as crystal nuclei.

Background Art

The sewage generated by large-scale farms is mainly high-concentration, high-ammonia nitrogen, high-suspended solids, and difficult to treat "three highs" sewage. 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 sewage 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.

However, the conventional pretreatment precipitation 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

The technical problem to be solved by the present invention is to provide a method for using micro-sand as crystallization nuclei to quickly combine suspended matter in water with flocs, thereby solving the disadvantages of traditional sedimentation separation 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. The present invention uses micro-sand particles and chemical flocculants to strengthen flocs and thus improve the sedimentation performance of suspended matter in water; the internal structure of the filler is utilized to not only even out the hydraulic distribution, but also to promote the water flow to continuously change direction during the rising process. The activated sludge will be intercepted due to the effect of inertia, thereby further improving the solid-liquid separation efficiency of the activated sludge.

In order to solve the above technical problems, the present invention provides the following technical solutions: 5. A method for rapidly combining suspended matter in water with flocs by using micro-sand as crystallization nuclei, comprising the following steps:

S1, introducing the sewage to be treated into the water inlet pipe, and introducing the flocculant into the opening of the water inlet pipe, and performing preliminary mixing in the water inlet pipe to obtain a first mixture;

S2. Introducing the first mixture into a sedimentation tank for mixed sedimentation. A mixing zone filled with VF filler and a sedimentation zone introduced with micro sand are arranged in sequence from top to bottom in the sedimentation tank, and a water outlet pipe is inserted laterally above the VF filler in the mixing zone, one end of the water outlet pipe is a water outlet end, and the other end is a closed end, and the closed end extends into the mixing zone of the sedimentation tank. Drainage outlets arranged at intervals are opened on the top of the side of the water outlet pipe along its axial direction, so that clean water from above the mixing zone enters the water outlet pipe through the drainage outlet and is discharged; clean water and mud and sand sediments are obtained in the upper and lower parts of the sedimentation tank respectively through the mixed sedimentation.

Preferably, in S1, the flocculant is an iron salt or an organic flocculant or a composite flocculant. For example, 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.

Preferably, the flocculant includes any one of polyferric chloride, polyferric sulfate, polyacrylamide, or a combination of polyaluminum chloride and polyferric sulfate.

Preferably, the flocculant is polyferric sulfate. More preferably, the amount of the flocculant used is 100-2000 mg/L based on the mass of ferric sulfate relative to the sewage to be treated. This preferred solution can accelerate the destabilization of pollutants and is more conducive to the subsequent formation of flocs after pollutant adsorption.

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

Preferably, 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.

Preferably, the micro-sand is introduced from below the side of the sedimentation zone.

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.

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.

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.

The mud and sand sediment can be subsequently separated to obtain sludge and micro-sand, and the micro-sand is recycled.

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

In the above scheme, flocculants are added to the water inlet pipe, micro-sand is added between the VF filler and the bottom aeration, and micro-sand particles and chemical flocculants are used to strengthen the flocs to improve the sedimentation performance of suspended matter in the water. Micro-sand is used as a crystallization nucleus and mixed with tiny flocs in the sewage. The process of rapid combination of micro-sand and flocs requires contact and collision, and the particles can hit the wall to intercept heavier flocs. By arranging VF fillers in the mixing zone and utilizing the internal structure of the fillers, not only the hydraulic distribution is uniform, but also the direction of the water flow is constantly changed during the rising process, solving the problem of uniform mixing of large amounts of water, and it is more suitable for combination with micro-sand crystallization nuclei; the activated sludge in the wastewater will be intercepted by the filler due to inertia, further improving the solid-liquid separation efficiency of the activated sludge. At the same time, the upward water flow is used to suspend the already formed flocs to form a stable sludge layer. The incoming water not only separates the activated sludge through the action of comprehensive force, but also needs to be treated through the interception, contact and coagulation of the sludge layer, which greatly improves the treatment efficiency and ensures the stability of the effluent.

This method of using hydraulic mixing solves the problem of large amounts of water being difficult to mix, and can make flocculants and micro-sand mix efficiently and quickly. Coagulants are added to the water to destabilize the suspended matter and colloidal particles in the water, and then micro-sand carrier particles with a higher density are added, so that the destabilized impurity particles use the micro-sand carrier as the floc nucleus. Through the bridging adsorption effect of the polymer chain and the sedimentation and netting effect of the micro-sand particles, alum flowers with a higher density are quickly generated. Under the separation effect of the filler, the sedimentation time is greatly shortened and the treatment effect is improved. Micro-sand can accelerate the flocculation and compaction, increase the volume of floc particles, shorten the residence time of the sedimentation tank, and achieve rapid solid-liquid separation.

The treatment method of the present invention organically combines flocculants, micro-sand, VF fillers and aeration in a specific structure, can perform rapid and efficient mixing, greatly shorten the sedimentation time, improve the sedimentation efficiency, and has a good sedimentation effect; and can achieve continuous discharge of purified water.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of the present invention.

FIG. 2 is a schematic diagram of a structure of a filler.

[reference numerals]

1. Sedimentation tank, 11. Mixing zone, 12. Sedimentation zone, 2. Water inlet pipe, 3. Flocculant inlet pipe, 4. Micro sand inlet pipe, 5. Aeration zone, 6. Water outlet pipe, 61. Drainage outlet.

DETAILED DESCRIPTION

As shown in FIG1 , the present invention provides a method for rapidly combining suspended matter in water into flocs by using microsand as crystallization nuclei, comprising the following steps:

S1, introducing the sewage to be treated into the water inlet pipe 2, and connecting the opening on the water inlet pipe 2 with the flocculant inlet pipe 3 to introduce the flocculant, and performing preliminary mixing in the water inlet pipe 2 to obtain a first mixture;

S2. Introducing the first mixture into the sedimentation tank 1 for mixed sedimentation. The sedimentation tank 1 is provided with a mixing zone 11 filled with VF filler and a sedimentation zone 12 for introducing micro-sand in sequence from top to bottom. An aeration zone 5 is provided at the bottom of the sedimentation zone 12 for aeration. An outlet pipe 6 is inserted transversely above the VF filler in the mixing zone 11. One end of the outlet pipe 6 is the outlet end, and the other end is the closed end. The closed end extends into the mixing zone 11 of the sedimentation tank 1. The top of the side of the outlet pipe 6 is provided with drain ports 61 arranged at intervals along its axial direction, so that the clean water from above the mixing zone 11 enters the outlet pipe 6 through the drain port 61 and is discharged. After the mixed sedimentation, clean water and mud and sand sediments are obtained in the upper and lower parts of the sedimentation tank 1, respectively.

It can be understood that, in application, the water level is located above the VF filler and below the drain port 61 of the water outlet pipe 6 .

When in use, sewage enters the sedimentation tank 1 from the water inlet pipe 2, and before entering, it is mixed with the flocculant in the flocculant inlet pipe 3 for preliminary flocculation treatment, and then deeply mixed in the filler in the mixing zone 11 of the sedimentation tank 1. The pores in the filler make the hydraulic distribution and hydraulic mixing uniform, which promotes the treatment effect; at the same time, it is aerated and mixed with micro sand in the sedimentation zone 12 to accelerate the floc clumping and sedimentation, thereby shortening the residence time in the sedimentation tank.

In the present invention, the flocculants and other high-density components in the sewage sink into the sedimentation zone 12 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.

The sewage to be treated 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 then adsorbed into the activated sludge flocs, separated by precipitation, and a large amount of water that meets the standards is obtained.

The VF filler of the present invention is an existing product, such as the VF filler of the applicant's early patent CN106044876B, which will not be described in detail here.

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

Preferably, the filler is a spiral pore structure or a honeycomb structure (as shown in FIG. 2 ).

Preferably, the bottom of the sedimentation tank 1 is conical and a mud and sand sediment discharge outlet is provided at the bottom.

Preferably, the micro-sand is introduced from below the side of the sedimentation area 11 , and a micro-sand inlet pipe 4 is provided below the side of the sedimentation area 11 .

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.

Example 1

The method of using micro sand as crystallization nuclei to rapidly combine suspended matter in water with flocs is carried out in a device as shown in FIG1 , and comprises:

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

S2. Introduce the first mixture into the sedimentation tank 1 for mixed sedimentation. A mixing zone 11 filled with VF filler and a sedimentation zone 12 for introducing micro sand are arranged from top to bottom in the sedimentation tank 1, and aeration is carried out at the bottom of the sedimentation tank 1. After the mixed sedimentation, clean water and mud and sand sediment are obtained in the upper and lower parts of the sedimentation tank 1 respectively. The filling height of the VF filler is 0.6m.

The sewage in this example contains COD, ammonia nitrogen, total nitrogen, SS, total phosphorus, PH, etc. When the flocculant is added at 1.5 mg/mL, larger and more flocs are produced, and the amount of adsorbed sand is relatively large.

Example 2

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

In this embodiment, the sedimentation effect of the water sample and the state of the supernatant are slightly different from those in Embodiment 1, but the amount of sand lost with the flocs during separation is 30% more than that in Embodiment 1, and the loss is the largest.

Example 3

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

In this embodiment, the amount of flocculant in water is insufficient, resulting in small flocs, which results in the amount of micro-sand attached to the flocs being 20% less than that in embodiment 1, and the amount of sand lost with the flocs during separation is also less.

Comparative Example 1

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

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 opaque, with a large number of fine suspended particles.

Comparative Example 2

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

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.

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 (7)

1. The method for quickly combining suspended matters in water with flocs by taking micro sand as crystallization nucleus is characterized by comprising the following steps:

S1, introducing sewage to be treated into a water inlet pipe, introducing a flocculating agent into an upper opening of the water inlet pipe, and primarily mixing in the water inlet pipe to obtain a first mixture;

s2, introducing the first mixture into a sedimentation tank for mixed sedimentation, sequentially arranging a mixing region filled with VF filler, a sedimentation region for introducing micro sand and the bottom of the sedimentation region from top to bottom in the sedimentation tank, transversely inserting a water outlet pipe above the VF filler in the mixing region, wherein one end of the water outlet pipe is a water outlet end, the other end of the water outlet pipe is a closed end, the closed end extends into the mixing region of the sedimentation tank, and the top of the side surface of the water outlet pipe is provided with water outlets which are arranged at intervals along the axial direction of the water outlet pipe, so that purified water from the upper part of the mixing region enters the water outlet pipe through the water outlets and is discharged; respectively obtaining purified water and silt sediment at the upper part and the lower part of the sedimentation tank through the mixed sediment;

The VF filler is in a spiral pore structure or a honeycomb structure;

The micro sand is used as crystallization nucleus to be mixed with micro flocs in sewage, the process of combining the micro sand and the flocs rapidly needs to be contacted and collided, and particles can collide with walls to intercept heavier flocs; by arranging VF filler in the mixing zone, the internal structure of the filler is utilized, so that not only is the hydraulic distribution uniform, but also the direction is continuously changed due to potential in the water flow rising process; activated sludge in the wastewater is trapped by the filler under the action of inertia.

2. The method for rapid binding of suspended solids in water using microsilica as a crystallization nucleus according to claim 1, wherein the flocculant comprises any one of poly ferric chloride, poly ferric sulfate, and polyacrylamide.

3. The method for rapid binding of suspended solids in water using microsilica as a crystallization nucleus according to claim 1, wherein the flocculant is a combination of polyaluminum chloride and polymeric ferric sulfate.

4. The method for rapid binding of suspended solids in water according to claim 1, wherein the flocculant is polymeric ferric sulfate.

5. The method for rapid binding of suspended solids in water by using micropills as crystallization nuclei according to claim 4, wherein the flocculant is used in an amount of 100 to 2000mg/L based on the mass of ferric sulfate relative to the sewage to be treated.

6. The method for rapid binding of suspended solids in water using microsilica as a crystallization nucleus according to claim 1, wherein the filling height of the VF filler is 0.6-2.7m.

7. The method for rapid binding of suspended solids in water to flocs using microsilica as a crystallization nucleus according to claim 1, wherein the microsilica is introduced from below the side of the sedimentation zone.