CN104909460B - Porosity denitrogenation dephosphorizing filler for artificial swamp and preparation method thereof - Google Patents

Abstract

The invention discloses a preparation method of a porous filler for denitrification and dephosphorization used in artificial wetlands, which comprises the following steps: measuring sand, Yunnan red soil, cement, quicklime, gypsum, and water according to the weight formula ratio, and then stirring evenly to form a mixture The slurry is put into the pouring mixer; the aluminum powder is made into a suspension according to the measurement, and put into the pouring mixer before pouring; the pouring mixer discharges the material and pours it into the mold to obtain a green body; Under the condition of ℃, carry out gas generation and initial setting for 1.5-2 hours to obtain rough filler; after the rough filler is statically stopped for initial curing and reaches the cutting strength, it is then cut; the cut rough filler is autoclaved and cured, that is have to. The filler prepared by the invention is used for sewage treatment, has light bulk density, stable chemical properties, easy film formation, large porosity, high mechanical strength, excellent phosphorus removal performance and good ammonia nitrogen removal effect.

Description

Porous nitrogen and phosphorus removal filler for constructed wetland and preparation method thereof

technical field

The invention belongs to the technical field of environmental protection, and in particular relates to a preparation method of a porous filler for denitrification and dephosphorization used in artificial wetlands.

Background technique

There are three main elements in constructed wetland sewage purification: filler matrix, plants and microorganisms. Among them, filler is the main place for sewage treatment, and pollutants are directly removed through interception, filtration, adsorption, precipitation and other functions.

Among the fillers widely used at present, whether they are traditional natural fillers (gravel, zeolite, limestone, etc.) Poor effect and other issues. Yunnan red soil is the most widely distributed soil type in Yunnan. The unique weathering conditions in the mountains of Yunnan make the content of Fe ₂ O ₃ and TiO ₂ in Yunnan red soil much higher than that in other regions. Yunnan red soil has a high potential for pollution removal, but the direct The use of laterite as a water treatment substrate has problems such as low hydraulic load and easy clogging.

Contents of the invention

The object of the present invention is to provide a method for preparing a porous filler for nitrogen and phosphorus removal for constructed wetlands in view of the above-mentioned deficiencies in the prior art. The filler involved in the present invention is a man-made product. Through a special manufacturing method, it forms a kind of light weight, high strength, stable properties, large porosity, good nitrogen and phosphorus removal effects, and is suitable for various scales of artificial wetlands and ecological treatment. Engineered water treatment fill.

The purpose of the present invention is achieved through the following technical solutions:

The invention relates to a method for preparing a porous filler for denitrification and dephosphorization used in constructed wetlands. The method comprises the following steps:

A. Measure sand, Yunnan laterite, cement, quicklime, gypsum, and water according to the weight formula ratio and stir evenly to make a mixed slurry, and put it into a pouring mixer;

B. Make the aluminum powder into a suspension with a mass concentration of 5-7% according to the measurement, and put it into the pouring mixer before pouring;

C. The pouring mixer discharges the material and pours it into the mould, so as to obtain the green body;

D. The green body cast in step C is subjected to gas generation and initial setting at 50-70°C for 1.5-2 hours to obtain coarse filler;

E. After the rough filler is statically stopped and initially cured to reach the cutting strength, it is cut; the cut rough filler is autoclaved and cured to obtain the porous filler for denitrification and phosphorus removal.

In the present invention, the Yunnan red soil contains higher Fe and Al active oxides, and its phosphorus removal performance is obviously better than that of the brick red soil and red red soil in the southeast region. If it is replaced with other laterite, the phosphorus removal effect will decrease.

In the present invention, after 1.5-2 hours of gas generation in step D, foam generation is basically completed, and the subsequent steam pressure curing further realizes rapid curing and molding of the filler.

As a preferred technical solution, according to the mass percentage of the total weight of raw materials, sand is 20-25%, Yunnan red soil is 15-20%, cement is 5-7%, quicklime is 9-12%, gypsum is 1.6-2%, and aluminum powder is 0.05-2%. 0.07%, water 38-43%.

As a preferred technical solution, in step B, the suspension is put into a pouring mixer 1 to 2 minutes before pouring.

As an optimal technical solution, in step C, before the pouring mixer discharges the material and pours it into the mould, the temperature of the slurry before pouring should be controlled to be 35-38°C.

As a preferred technical solution, the temperature of the slurry before pouring is controlled by steam heating.

As a preferred technical solution, the autoclaving curing is constant pressure steaming for 6-10 hours, the steam pressure used is 1.0-1.5 MPa, and the steaming temperature is 180-200°C.

Compared with the prior art, the present invention has the following beneficial effects:

1. The production of filler is convenient, and the currently popular aerated concrete block brick production equipment can be fully utilized. The degree of mechanization is high, the cycle is short, and the production cost is low.

2. Since the filler contains a large number of uniform and fine pores, the specific surface area of the filler is greatly increased, and the pollutants can be effectively adsorbed, filtered and retained;

3. The filling void ratio is large, up to about 50%, and at the same time, it provides a good growth environment for the growth of microorganisms, which is conducive to the degradation of pollutants such as COD and ammonia nitrogen by microorganisms;

4. The specific gravity of the filler is small, the weight is light, and the labor cost is low in practical application.

5. Give full play to the phosphorus removal characteristics of Yunnan red soil itself, and have excellent phosphorus removal performance, far exceeding traditional fillers.

6. It has high mechanical strength, anti-extrusion, and is not easy to break after long-term immersion, which can ensure the long-term operation of the sewage treatment system.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Figure 1 is a schematic diagram of the plane layout of the tail water deep treatment project of the membrane bioreactor;

Among them, 1 is Dali Road, 2 is an aerobic pond, 3 is a surface flow constructed wetland, 4 is a horizontal subsurface flow wetland, and 5 is an outlet pond.

detailed description

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make some adjustments and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

Example 1

This example relates to a porous nitrogen and phosphorus removal filler used in constructed wetlands, which uses sand, Yunnan red soil, cement, quicklime, gypsum, aluminum powder, water, etc. as the main raw materials, and uses steam pressurization to produce foam Yunnan red soil is immobilized to make porous materials.

The specific preparation mainly includes the following process steps:

1. According to the mass percentage of the total weight of raw materials, mix 20% of sand, 19% of Yunnan red soil, 5% of cement, 10.93% of quicklime, 2% of gypsum, and 43% of water to make a mixed slurry. The measured slurry Put into pouring mixer;

2. Make a suspension of 0.07% aluminum powder, stir for about 30s, and put the stirred suspension into the pouring mixer about 1 minute before pouring;

3. The temperature of the slurry should reach 35-38°C before pouring. If the temperature is not enough, it can be heated by steam;

4. The pouring mixer discharges the material and pours it into the mold;

5. The cast green body is subjected to gas generation and initial setting at 60°C for 1.8 hours;

6. After the static stop and initial curing reaches the cutting strength, cut according to the actual application needs;

7. Pull the cut uniform packing into the kettle for autoclaving and curing. The constant pressure steam curing time is 8 hours, the steam pressure is 1.3MPa, and the temperature is 190°C.

8. After the curing is completed, it will be made into a uniform porosity denitrification and phosphorus removal filler.

Performance tests were carried out on the prepared porous packing for nitrogen and phosphorus removal. The specific surface area was 4.7×10 ⁵ cm ² /g, the phosphorus adsorption capacity was 5.59mg/g, the compressive strength was 3.5Mpa, and the bulk density was 0.85g/cm ³ .

In the present invention, conventional firing cannot be used in step 7, because the conventional firing temperature is not easy to control, and if the temperature exceeds 400 degrees, the performance will drop significantly.

Example 2

This example relates to a porous nitrogen and phosphorus removal filler used in constructed wetlands, which uses sand, Yunnan red soil, cement, quicklime, gypsum, aluminum powder, water, etc. as the main raw materials, and uses steam pressurization to produce foam Yunnan red soil is immobilized to make porous materials.

The specific preparation mainly includes the following process steps:

1. According to the mass percentage of the total weight of raw materials, mix 23% of sand, 15% of Yunnan red soil, 7% of cement, 12% of quicklime, 1.6% of gypsum, and 41.35% of water to make a mixed slurry. The measured slurry Put into pouring mixer;

2. Make a suspension of 0.05% aluminum powder, stir for about 30s, and put the stirred suspension into the pouring mixer about 2 minutes before pouring;

3. The temperature of the slurry should reach 35-38°C before pouring. If the temperature is not enough, it can be heated by steam;

4. The pouring mixer discharges the material and pours it into the mold;

5. The cast green body is subjected to gas generation and initial setting at 50°C for 2 hours;

6. After the static stop and initial curing reaches the cutting strength, cut according to the actual application needs;

7. Pull the cut uniform filler into the kettle for autoclaving and curing. The constant pressure steam curing time is 6 hours, the steam pressure is 1.0MPa, and the temperature is 200°C.

8. After the curing is completed, it will be made into a uniform porosity denitrification and phosphorus removal filler.

Performance tests were carried out on the prepared porous packing for nitrogen and phosphorus removal. The specific surface area was 5.2×10 ⁵ cm ² /g, the phosphorus adsorption capacity was 5.30mg/g, the compressive strength was 3.2Mpa, and the bulk density was 0.82g/cm ³ .

Example 3

This example relates to a porous nitrogen and phosphorus removal filler used in constructed wetlands, which uses sand, Yunnan red soil, cement, quicklime, gypsum, aluminum powder, water, etc. as the main raw materials, and uses steam pressurization to produce foam Yunnan red soil is immobilized to make porous materials.

The specific preparation mainly includes the following process steps:

1. According to the mass percentage of the total weight of raw materials, mix 25% of sand, 20% of Yunnan red soil, 6% of cement, 9% of quicklime, 1.94% of gypsum, and 38% of water to make a mixed slurry. The measured slurry Put into pouring mixer;

2. Make a suspension of 0.06% aluminum powder, stir for about 30s, and put the stirred suspension into the pouring mixer about 1 minute before pouring;

3. The temperature of the slurry should reach 35-38°C before pouring. If the temperature is not enough, it can be heated by steam;

4. The pouring mixer discharges the material and pours it into the mold;

5. The cast green body undergoes gas generation and initial setting at 70°C for 1.5 hours;

6. After the static stop and initial curing reaches the cutting strength, cut according to the actual application needs;

7. Pull the cut uniform filler into the kettle for autoclaving and curing. The constant pressure steam curing time is 10 hours, the steam pressure is 1.5MPa, and the temperature is 180°C.

8. After the curing is completed, it will be made into a uniform porosity denitrification and phosphorus removal filler.

Performance tests were carried out on the prepared porous packing for nitrogen and phosphorus removal. The specific surface area was 4.2×10 ⁵ cm ² /g, the phosphorus adsorption capacity was 5.02mg/g, the compressive strength was 3.5Mpa, and the bulk density was 0.89g/cm ³ .

Comparative example 1

This example relates to a porous filler for denitrification and dephosphorization used in constructed wetlands. The specific preparation mainly includes the following process steps:

1. According to the mass percentage of the total weight of raw materials, 10% of sand, 29% of Yunnan red soil, 5% of cement, 10.93% of quicklime, 2% of gypsum, and 43% of water are mixed evenly to make a mixed slurry. The measured slurry Put into pouring mixer;

2. Make a suspension of 0.07% aluminum powder, stir for about 30s, and put the stirred suspension into the pouring mixer about 1 minute before pouring;

3. The temperature of the slurry should reach 35-38°C before pouring. If the temperature is not enough, it can be heated by steam;

4. The pouring mixer discharges the material and pours it into the mold;

5. The cast green body is subjected to gas generation and initial setting at 60°C for 1.8 hours;

6. After the static stop and initial curing reaches the cutting strength, cut according to the actual application needs;

7. Pull the cut uniform packing into the kettle for autoclaving and curing. The constant pressure steam curing time is 8 hours, the steam pressure is 1.3MPa, and the temperature is 190°C.

8. After the curing is completed, it will be made into a uniform porosity denitrification and phosphorus removal filler.

Performance tests were carried out on the prepared porous packing for nitrogen and phosphorus removal. The specific surface area was 2.5×10 ⁵ cm ² /g, the phosphorus adsorption capacity was 2.16mg/g, the compressive strength was 4Mpa, and the bulk density was 1.1g/cm ³ .

Example 4

This example relates to the application of the present invention's porous filler for denitrification and dephosphorization in constructed wetlands-the deep treatment project of membrane bioreactor tail water in Shangguan Village, Xizhou Town, Dali City, Dali Bai Autonomous Prefecture, Yunnan Province.

The processing scale of the project is 300m ³ /d, covers an area of 8 mu, has no power consumption, and serves 3,483 villagers in Shangguan Village. The influent of the tail water treatment project is the effluent of the facultative membrane bioreactor, which meets the first-level A standard of the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002), and the effluent of this project meets the "Environmental Quality Standards for Surface Water" (GB3838 -2002) Class IV standard for surface water.

The schematic layout of the treatment project is shown in Figure 1. Along the parallel direction of Dali Road 1, there are aerobic ponds 2, surface flow constructed wetlands 3, horizontal subsurface flow wetlands 4 and outlet ponds 5.

Among them: the length of the first level aerobic pond is 25m, and the effective water depth is 1.5m. The surface flow wetland is 75m long and has an effective water depth of 0.6m. Aquatic crops such as water celery and coriander are planted. The horizontal subsurface flow wetland has two levels, the effective area is 400m ² , and the thickness of the filling layer is 1.3m. The second level uses the self-made filling in Example 1 of the present invention, and the upper layer is covered with soil with a thickness of 0.2m and planted with turf. It was officially put into operation in June 2014. After the tail water treatment wetland project is put into operation, the effluent ammonia nitrogen and TP can meet the surface water category IV standard of the "Surface Water Environmental Quality Standard" (GB3838-2002). L. This project provides an engineering demonstration for the improvement and improvement of sewage treatment facilities around Erhai Lake in Dali, Yunnan.

In summary, the present invention uses sand, Yunnan red soil, cement, quicklime, gypsum, aluminum powder, water, etc. as main raw materials, and utilizes the method of steam pressurization to produce foam to immobilize Yunnan red soil to make a porous material. Under the premise of taking advantage of the high porosity of the filler, the material has played the unique phosphorus removal performance of Yunnan red soil, making it have higher mechanical strength and larger adsorption capacity, and is suitable for various scales of constructed wetlands and ecological treatment. Engineering, nitrogen and phosphorus removal effect is good.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (4)

1. A preparation method for a porous denitrification and dephosphorization filler for constructed wetlands, characterized in that, the method may further comprise the steps: A. Stir sand, Yunnan laterite, cement, quicklime, gypsum, and water evenly to make a mixed slurry, and put it into the pouring mixer; B. Make aluminum powder into a suspension with a mass concentration of 5-7%, and put it into a pouring mixer before pouring; C. The pouring mixer discharges the material and pours it into the mould, so as to obtain the green body; D. The green body cast in step C is subjected to gas generation and initial setting at 50-70°C for 1.5-2 hours to obtain coarse filler; E. After the rough filler is statically stopped and initially cured to reach the cutting strength, it is cut; the cut rough filler is autoclaved and cured to obtain the porous nitrogen and phosphorus removal filler; According to the mass percentage of the total weight of raw materials, 20-25% of sand, 15-20% of Yunnan red soil, 5-7% of cement, 9-12% of quicklime, 1.6-2% of gypsum, 0.05-0.07% of aluminum powder, and 38% of water ~43%; The autoclaving curing is constant pressure steaming for 6-10 hours, the steam pressure used is 1.0-1.5 MPa, and the steaming temperature is 180-200°C. 2. The method for preparing the porous filler for denitrification and dephosphorization of constructed wetlands according to claim 1, characterized in that, in step B, the suspension is put into a pouring mixer 1-2 minutes before pouring. 3. the preparation method of the porous denitrification and dephosphorization filler that is used for artificial wetland according to claim 1, it is characterized in that, in step C, before pouring mixer blowing into mould, control slurry temperature before pouring is 35～38℃. 4. The method for preparing the porous nitrogen and phosphorus removal filler for constructed wetland according to claim 3, characterized in that the temperature of the slurry before pouring is controlled by steam heating.