CN111499000B - A kind of artificial wetland filler and preparation method thereof - Google Patents

Abstract

The invention discloses a constructed wetland filler and a preparation method thereof, belonging to the technical field of environmental protection. It includes: by weight, 50-100 parts of activated sludge, 10-40 parts of blast furnace slag, 1-20 parts of carbon slag, 1-10 parts of bentonite, 1-5 parts of nitrogen adsorbent and 1-5 parts of phosphorus adsorbent share. The raw material of the invention is cheap, easy to obtain, simple to prepare, and the prepared filler has the advantages of high strength, high hardness, not easy to decompose, good water permeability, and strong adsorption to phosphorus and nitrogen.

Description

A kind of artificial wetland filler and preparation method thereof

technical field

The invention relates to the technical field of environmental protection, in particular to a constructed wetland filler and a preparation method thereof.

Background technique

At present, my country's water environment is deteriorating day by day, with problems such as eutrophication of lakes, red tides in coastal waters, and organic pollution of rivers and reservoirs, threatening the safety of water diversion for residents and the health of the people. Constructed wetland filler treatment has the characteristics of good water purification effect, low infrastructure operation cost, low energy consumption, simple maintenance and management, strong shock load resistance, etc., and can provide habitat for wild animals and improve the aesthetic value of ecological landscape, so It has been widely used in domestic sewage, industrial wastewater, agricultural non-point source sewage, urban storm runoff and eutrophic water bodies. However, according to the existing engineering practice, the denitrification and dephosphorization ability of constructed wetland packing is weak.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a constructed wetland filler and a preparation method thereof, so as to solve the problem of weak denitrification and dephosphorization capability of the existing constructed wetland filler.

The technical scheme that the present invention solves the above-mentioned technical problems is as follows:

A constructed wetland filler, comprising: by weight, 50-100 parts of activated sludge, 10-40 parts of blast furnace slag, 1-20 parts of fly ash, 1-10 parts of bentonite, 1-5 parts of nitrogen adsorbent and Phosphorus adsorbent 1-5 parts.

The activated sludge used in the present invention is left over from the sludge dewatering process of the sewage treatment plant, and contains a large amount of flocculants, mainly PAM and PAC, and these flocculants are retained in the sludge. Therefore, the activated sludge used in the present invention contains a large amount of residual effective flocculation components, and these active components can play the role of adsorbing pollutants and purifying sewage on the constructed wetland. In addition, the sludge residue left in the sewage treatment plant is used to support the filler, which is difficult to deal with the remaining sludge, and realizes the environmental governance concept of "treating waste with waste" and "turning waste into treasure".

In the filler of the present application, the activated sludge contains a large amount of effective flocculation components, which can efficiently retain nitrogen and phosphorus elements in the water body for the growth of plants planted in the soil layer above it. By using blast furnace slag, bentonite and fly ash as auxiliary fillers, the fillers have the advantages of rough surface, high porosity, uniform distribution of microporous structure, large specific surface area and high mechanical strength, which can improve the hydraulic performance of constructed wetlands. Provides a larger attachment area for microorganisms, enhances the system's removal efficiency of pollutants, and also prevents wetland clogging. And by adding nitrogen adsorbent and phosphorus adsorbent, the adsorption effect of the filler on nitrogen and phosphorus is optimized. high cost.

Further, in a preferred embodiment of the present invention, the above-mentioned constructed wetland fillers include: by weight, 60-80 parts of activated sludge, 20-30 parts of blast furnace slag, 5-15 parts of fly ash, and 3 parts of bentonite. -7 parts, 1-5 parts nitrogen adsorbent and 1-5 parts phosphorus adsorbent.

Further, in a preferred embodiment of the present invention, the water content of the activated sludge is lower than 60%.

Further, in a preferred embodiment of the present invention, the preparation method of the above-mentioned nitrogen adsorbent comprises the following steps:

(i) Dissolve sodium lignosulfonate and activated carbon in an acetic acid solution with a mass of (80-100):1 to prepare a 1-10wt% solution, and then add dropwise to a sodium hydroxide solution with a concentration of 10-20wt%, Stir and filter to obtain beads;

(ii) Soak the beads in an aqueous solution of lanthanum chloride with a concentration of 1-5g/mL, fully absorb them at 30-50°C, filter and add them to epichlorohydrin, adjust the pH to 8-10, and then add Potassium persulfate, react at 50-70℃ for 3-5h to obtain nitrogen adsorbent;

Wherein, the mass ratio of beads, epichlorohydrin and potassium persulfate is: 1:(6-8):(0.01-0.02).

Further, in a preferred embodiment of the present invention, the preparation method of the above-mentioned phosphorus adsorbent comprises the following steps:

(i) immersing the activated bagasse in a cerium chloride solution with a concentration of 3-7g/mL, adjusting the pH to 10-12, stirring and reacting for 1-2h, washing and drying with ethanol to obtain the initial adsorbent;

(ii) Immerse the initial adsorbent in an aqueous solution of nano-zirconia with a concentration of 1-2 g/mL, filter, wash and dry, and then calcinate at a temperature of 300-600 °C for 2-3 hours to obtain a phosphorus adsorbent.

Further, in a preferred embodiment of the present invention, the preparation step of the activated bagasse in the above step (i) includes: adding the bagasse into the culture solution, adding acetic acid-sodium acetate buffer to the culture solution, and adjusting the pH to 3. After adding white rot fungi, react at 30°C-35°C for 36h-45h, take out, dry and pulverize to a particle size of 50 meshes to obtain modified bagasse; among them, the bagasse, culture solution and white rot fungi are The mass ratio is 1:(10-12):(3-5); the addition amount of acetic acid-sodium acetate buffer is 10wt%-20wt% of the culture solution; the culture solution includes the following components by weight: 2 parts of yeast powder , 10.4 parts of vitamin B, 1.5 parts of glucose, 1.5 parts of soluble starch, 0.2 part of KH ₂ PO ₄ and 0.5 part of MgSO ₄ ·7H ₂ O.

The preparation method of the above-mentioned constructed wetland filler, comprises the following steps:

(1) After fully grinding the blast furnace slag with a particle size of less than 200nm, add the activator and stir and mix evenly, then roast at 400-600 ℃ for 0.5-1h; the mass ratio of blast furnace slag and activator added is (100-150) :1;

(2) After grinding the calcined blast furnace slag again, add water to mix evenly, heat up from room temperature to 80-90 °C, keep it for 1-3 hours, and then dry it at 70-90 °C;

(3) Dissolving stearic acid in ether, heating it in a water bath to make it completely dissolved to prepare a solution of 0.01-0.05g/mL, adding the blast furnace slag, bentonite and fly ash after drying in step (2), stirring and mixing evenly, prepared mixture;

(4) Add nitrogen adsorbent and phosphorus adsorbent to the mixture, stir and mix evenly, and stir and mix with activated sludge evenly, press and shape, and then air-dry to obtain a constructed wetland filler.

Further, in a preferred embodiment of the present invention, the activator in the above step (1) is sodium hydroxide.

The present invention has the following beneficial effects:

1. The activated carbon added in the nitrogen adsorbent of the present invention has strong adsorption and catalytic performance, and has strong adsorption capacity to organic pollutants dissolved in water and some toxic heavy metals; the added sodium lignosulfonate Contains a large number of linear and polar groups, which can improve the adsorption of ammonia nitrogen. In addition, by adding lanthanum chloride as a modifier, the adsorption capacity of activated carbon and sodium lignosulfonate for nitrogen is assisted to improve, thereby improving the nitrogen adsorption effect of the nitrogen adsorbent.

2. The present invention provides the adaptability of the phosphorus adsorbent to the environment by making a biochar-based phosphorus adsorbent, adding nano zirconium dioxide, and the nano zirconium dioxide mainly interacts with phosphoric acid through chelation, covalent bonds or coordination bonds. The roots are bound and fixed on the surface of the phosphorus adsorbent to improve the adsorption effect of phosphorus.

3. The raw materials of the present invention are cheap, easy to obtain, simple to prepare, and the prepared filler has the advantages of high strength, high hardness, not easy to decompose, good water permeability, and strong adsorption to phosphorus and nitrogen.

Detailed ways

The principles and features of the present invention will be described below with reference to the embodiments. The examples are only used to explain the present invention, but not to limit the scope of the present invention. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

Example 1:

The constructed wetland filler in this embodiment includes: by weight, 50 parts of activated sludge, 10 parts of blast furnace slag, 1 part of fly ash, 1 part of bentonite, 1 part of nitrogen adsorbent and 1 part of phosphorus adsorbent.

Wherein, the preparation method of nitrogen adsorbent comprises the following steps:

(i) dissolving sodium lignosulfonate and activated carbon in an acetic acid solution at a mass ratio of 80:1 to prepare a 1wt% solution, then adding dropwise to a sodium hydroxide solution with a concentration of 10wt%, stirring and filtering to obtain beads;

(ii) The beads were soaked in an aqueous solution of lanthanum chloride with a concentration of 1 g/mL, and fully adsorbed at 30 °C. After filtration, they were added to epichlorohydrin, adjusted to pH 8, and then potassium persulfate was added. React at ℃ temperature for 3-5h to obtain nitrogen adsorbent;

Wherein, the mass ratio of beads, epichlorohydrin and potassium persulfate is: 1:6:0.01.

The preparation method of phosphorus adsorbent comprises the following steps:

(i) Immerse the activated bagasse in a cerium chloride solution with a concentration of 3 g/mL, adjust the pH to 10, stir and react for 1 hour, wash and dry with ethanol to obtain an initial adsorbent; the preparation steps of the activated bagasse include: : Add bagasse into the culture solution, add acetic acid-sodium acetate buffer to the culture solution, adjust the pH to 3, add white rot bacteria, react at 30°C for 36h, take out, dry and pulverize until the particle size is 50 To obtain modified bagasse; wherein the mass ratio of bagasse, culture solution and white rot bacteria is 1:10:3; the addition of acetic acid-sodium acetate buffer is 10wt% of the culture solution; the culture solution includes the following parts by weight Ingredients: 2 parts of yeast powder, 10.4 parts of vitamin B, 1.5 parts of glucose, 1.5 parts of soluble starch, 0.2 part of KH ₂ PO ₄ and 0.5 part of MgSO ₄ ·7H ₂ O .

(ii) The initial adsorbent was immersed in an aqueous solution of nano-zirconia with a concentration of 1 g/mL, filtered, washed and dried, and then calcined at 300°C for 2 hours to obtain a phosphorus adsorbent.

The preparation method of the preparation method of the constructed wetland filler of the present embodiment comprises the following steps:

(1) After fully grinding the blast furnace slag with a particle size of 150nm, adding an activator and stirring to mix it uniformly, roasting at 400 ° C for 0.5h; the mass ratio of blast furnace slag and activator added is 100:1;

(2) After grinding the calcined blast furnace slag again, add water to mix evenly, heat it up from room temperature to 80°C, hold it for 1 hour, and then dry it at 70°C;

(3) Dissolving stearate in ether, heating it in a water bath to make it completely dissolved to prepare a solution of 0.01 g/mL, adding the blast furnace slag, bentonite and fly ash after drying in step (2), stirring and mixing evenly to obtain the Mixture;

(4) Add nitrogen adsorbent and phosphorus adsorbent to the mixture, stir and mix evenly, and stir and mix with activated sludge evenly, press and shape, and then air-dry to obtain a constructed wetland filler.

Example 2:

The constructed wetland filler in this embodiment includes: by weight, 60 parts of activated sludge, 20 parts of blast furnace slag, 5 parts of fly ash, 3 parts of bentonite, 2 parts of nitrogen adsorbent and 2 parts of phosphorus adsorbent.

Wherein, the preparation method of nitrogen adsorbent comprises the following steps:

(i) dissolving sodium lignosulfonate and activated carbon in an acetic acid solution at a mass ratio of 90:1 to prepare a 5wt% solution, then adding dropwise to a sodium hydroxide solution with a concentration of 15wt%, stirring and filtering to obtain beads;

(ii) Soak the beads in an aqueous solution of lanthanum chloride with a concentration of 3g/mL, and fully absorb them at 40°C. After filtration, add them to epichlorohydrin, adjust the pH to 9, and then add potassium persulfate at 60°C. Reaction at ℃ temperature for 4h to obtain nitrogen adsorbent;

Wherein, the mass ratio of beads, epichlorohydrin and potassium persulfate is: 1:7:0.015.

The preparation method of phosphorus adsorbent comprises the following steps:

(i) Immerse the activated bagasse in a cerium chloride solution with a concentration of 5 g/mL, adjust the pH to 11, stir and react for 1.5 hours, wash and dry with ethanol to obtain the initial adsorbent; the preparation steps of the activated bagasse The method includes: adding bagasse into the culture solution, adding acetic acid-sodium acetate buffer to the culture solution, adjusting the pH to 3, adding white rot bacteria, reacting at 32°C for 40 hours, taking out, drying and crushing to a particle size of 50 meshes to obtain modified bagasse; wherein the mass ratio of bagasse, culture solution and white rot bacteria is 1:11:4; the addition of acetic acid-sodium acetate buffer is 15wt% of the culture solution; the culture solution includes the following weights The components of the serving: 2 parts of yeast powder, 10.4 parts of vitamin B, 1.5 parts of glucose, 1.5 parts of soluble starch, 0.2 part of KH ₂ PO ₄ and 0.5 part of MgSO ₄ ·7H ₂ O.

(ii) The initial adsorbent was immersed in an aqueous solution of nano-zirconia with a concentration of 1.5 g/mL, filtered, washed and dried, and then calcined at 450°C for 3 hours to obtain a phosphorus adsorbent.

The preparation method of the preparation method of the constructed wetland filler of the present embodiment comprises the following steps:

(1) After fully grinding the blast furnace slag with a particle size of 150nm, adding an activator and stirring to mix it uniformly, roasting at 500 °C for 1 hour; the mass ratio of blast furnace slag and activator added is 120:1;

(2) After grinding the calcined blast furnace slag again, add water to mix evenly, heat it up from room temperature to 85°C, keep it for 2 hours, and then dry it at 80°C;

(3) Dissolving stearate in ether, heating it in a water bath to make it completely dissolved to prepare a solution of 0.03 g/mL, adding the blast furnace slag, bentonite and fly ash after drying in step (2), stirring and mixing evenly to obtain the Mixture;

(4) Add nitrogen adsorbent and phosphorus adsorbent to the mixture, stir and mix evenly, and stir and mix with activated sludge evenly, press and shape, and then air-dry to obtain a constructed wetland filler.

Example 3:

The constructed wetland filler in this embodiment includes: 70 parts by weight of activated sludge, 25 parts of blast furnace slag, 10 parts of fly ash, 5 parts of bentonite, 3 parts of nitrogen adsorbent and 3 parts of phosphorus adsorbent.

Wherein, the preparation method of nitrogen adsorbent comprises the following steps:

(i) dissolving sodium lignosulfonate and activated carbon in an acetic acid solution with a mass of 100:1 to prepare a 10wt% solution, then adding dropwise to a sodium hydroxide solution with a concentration of 20wt%, stirring and filtering to obtain beads;

(ii) Soak the beads in an aqueous solution of lanthanum chloride with a concentration of 5g/mL, and fully absorb them at 50°C. After filtration, add them to epichlorohydrin, adjust the pH to 10, and then add potassium persulfate, at 70 The nitrogen adsorbent was prepared by reacting at ℃ for 5h;

Wherein, the mass ratio of beads, epichlorohydrin and potassium persulfate is: 1:8:0.02.

The preparation method of phosphorus adsorbent comprises the following steps:

(i) Immerse the activated bagasse in a cerium chloride solution with a concentration of 3-7g/mL, adjust the pH to 12, stir and react for 2 hours, wash and dry with ethanol to obtain an initial adsorbent; the preparation steps of bagasse Including: adding bagasse into the culture solution, adding acetic acid-sodium acetate buffer to the culture solution, adjusting the pH to 3, adding white rot bacteria, reacting at 35°C for 45 hours, taking out, drying and pulverizing to a particle size of 50 meshes to obtain modified bagasse; wherein the mass ratio of bagasse, culture solution and white rot bacteria is 1:12:5; the addition of acetic acid-sodium acetate buffer is 20wt% of the culture solution; the culture solution includes the following weights The components of the serving: 2 parts of yeast powder, 10.4 parts of vitamin B, 1.5 parts of glucose, 1.5 parts of soluble starch, 0.2 part of KH ₂ PO ₄ and 0.5 part of MgSO ₄ ·7H ₂ O.

(ii) The initial adsorbent was immersed in an aqueous solution of nano-zirconia with a concentration of 2 g/mL, filtered, washed and dried, and then calcined at 600°C for 3 hours to obtain a phosphorus adsorbent.

The preparation method of the preparation method of the constructed wetland filler of the present embodiment comprises the following steps:

(1) After fully grinding the blast furnace slag with a particle size of 100 nm, add the activator and stir and mix evenly, and then roast at 600 °C for 1 hour; the mass ratio of blast furnace slag and activator added is 150:1;

(2) After grinding the calcined blast furnace slag again, add water and mix it uniformly, heat it up from room temperature to 90 °C, keep it for 3 hours, and then dry it at 90 °C;

(3) Dissolving stearate in ether, heating it in a water bath to make it completely dissolved to prepare a solution of 0.05 g/mL, adding the blast furnace slag, bentonite and fly ash after drying in step (2), stirring and mixing evenly to obtain the Mixture;

(4) Add nitrogen adsorbent and phosphorus adsorbent to the mixture, stir and mix evenly, and stir and mix with activated sludge evenly, press and shape, and then air-dry to obtain a constructed wetland filler.

Example 4:

The constructed wetland filler in this embodiment includes: 80 parts by weight of activated sludge, 30 parts of blast furnace slag, 15 parts of fly ash, 7 parts of bentonite, 4 parts of nitrogen adsorbent and 4 parts of phosphorus adsorbent. Among them, the preparation methods of nitrogen adsorbent and phosphorus adsorbent are the same as those in Example 1.

The preparation method of the constructed wetland filler in this example is the same as that in Example 1.

Example 5:

The constructed wetland filler in this embodiment includes: by weight, 100 parts of activated sludge, 40 parts of blast furnace slag, 20 parts of fly ash, 10 parts of bentonite, 5 parts of nitrogen adsorbent and 5 parts of phosphorus adsorbent. Among them, the preparation methods of nitrogen adsorbent and phosphorus adsorbent are the same as those in Example 1.

The preparation method of the constructed wetland filler in this example is the same as that in Example 1.

Comparative Example 1

The constructed wetland filler in this comparative example includes: by weight, 70 parts of activated sludge, 25 parts of blast furnace slag, 10 parts of fly ash and 5 parts of bentonite.

The preparation method of the constructed wetland filler of this comparative example is consistent with the preparation method of the constructed wetland filler of Example 3.

Comparative Example 2

The formula of the constructed wetland filler of this comparative example is the same as that of Example 3, except that the preparation method is different.

The preparation method of the constructed wetland filler of this comparative example comprises the following steps:

The blast furnace slag is ground, and the ground blast furnace slag, activated sludge, fly ash, bentonite, nitrogen adsorbent and phosphorus adsorbent are stirred and mixed uniformly, and then compressed and formed, and then air-dried to obtain a constructed wetland filler.

Nitrogen and phosphorus adsorption tests were performed on the fillers prepared in the above examples 1-5 and the control. The test condition is to take 10 g of the packing module and add 15 mL of a solution containing 100 mg/L nitrogen and 25 mg/L phosphorus, and let it stand for 1 day.

Table 1 Nitrogen and phosphorus removal rates of constructed wetland fillers prepared in Examples and Comparative Examples

It can be seen from the above table that nitrogen adsorbent and phosphorus adsorbent are added in the embodiment of the present invention, and it can be seen that the removal rate of ammonia nitrogen and phosphorus is significantly higher than that in Comparative Example 1 without adding it. And compared with the control example 2, the activation treatment of blast furnace slag also improved the removal rate of ammonia nitrogen and phosphorus.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (6)

1. A constructed wetland filler is characterized in that, comprising: by weight, 50-100 parts of activated sludge, 10-40 parts of blast furnace slag, 1-20 parts of fly ash, 1-10 parts of bentonite, nitrogen adsorption 1-5 parts of agent and 1-5 parts of phosphorus adsorbent; wherein, the activated sludge is dewatered sludge containing PAM and PAC; The preparation method of the nitrogen adsorbent comprises the following steps: (i) Dissolve sodium lignosulfonate and activated carbon in an acetic acid solution with a mass of (80-100):1 to prepare a 1-10wt% solution, and then add dropwise to a sodium hydroxide solution with a concentration of 10-20wt%, Stir and filter to obtain beads; (ii) Soak the beads in an aqueous solution of lanthanum chloride with a concentration of 1-5g/mL, fully absorb them at 30-50°C, filter and add them to epichlorohydrin, adjust the pH to 8-10, and then add Potassium persulfate, react at 50-70℃ for 3-5h to obtain nitrogen adsorbent; Among them, the mass ratio of beads, epichlorohydrin and potassium persulfate is: 1:(6-8):(0.01-0.02); The preparation method of the phosphorus adsorbent comprises the following steps: (i) immersing the activated bagasse in a cerium chloride solution with a concentration of 3-7g/mL, adjusting the pH to 10-12, stirring and reacting for 1-2h, washing and drying with ethanol to obtain the initial adsorbent; (ii) Immerse the initial adsorbent in an aqueous solution of nano-zirconia with a concentration of 1-2 g/mL, filter, wash and dry, and then calcinate at a temperature of 300-600 °C for 2-3 hours to obtain a phosphorus adsorbent. 2. The constructed wetland filler according to claim 1, characterized in that, comprising: by weight, 60-80 parts of activated sludge, 20-30 parts of blast furnace slag, 5-15 parts of fly ash, 3-15 parts of bentonite 7 parts, 1-5 parts nitrogen adsorbent and 1-5 parts phosphorus adsorbent. 3. The constructed wetland filler according to claim 1 or 2, wherein the activated sludge has a water content of less than 60%. 4 . The constructed wetland filler according to claim 1 , wherein the preparation step of activating bagasse in step (i) of the phosphorus adsorbent preparation method comprises: adding bagasse into the culture solution, adding the bagasse into the culture solution 5 . Add acetic acid-sodium acetate buffer, adjust pH to 3, add white rot bacteria, react at 30°C-35°C for 36h-45h, take out, dry and pulverize to a particle size of 50 mesh to obtain modified bagasse; The mass ratio of bagasse, culture solution and white rot bacteria is 1:(10-12):(3-5); the addition amount of acetic acid-sodium acetate buffer is 10wt%-20wt% of the culture solution; the culture solution includes The following components in parts by weight: 2 parts of yeast powder, 10.4 parts of vitamin B, 1.5 parts of glucose, 1.5 parts of soluble starch, 0.2 part of KH ₂ PO ₄ and 0.5 part of MgSO ₄ ·7H ₂ O. 5. the preparation method of the constructed wetland filler according to any one of claim 1-4, is characterized in that, comprises the following steps: (1) After fully grinding the blast furnace slag with a particle size of less than 200nm, add the activator and stir and mix evenly, then roast at 400-600 ℃ for 0.5-1h; the mass ratio of blast furnace slag and activator added is (100-150) :1; (2) After grinding the calcined blast furnace slag again, add water to mix evenly, heat up from room temperature to 80-90 °C, keep it for 1-3 hours, and then dry it at 70-90 °C; (3) Dissolving stearic acid in ether, heating it in a water bath to make it completely dissolved to prepare a solution of 0.01-0.05g/mL, adding the blast furnace slag, bentonite and fly ash after drying in step (2), stirring and mixing evenly, prepared mixture; (4) Add nitrogen adsorbent and phosphorus adsorbent to the mixture, stir and mix evenly, and stir and mix with activated sludge evenly, press and form, and then air-dry to obtain a constructed wetland filler. 6 . The method for preparing a constructed wetland filler according to claim 5 , wherein the activator in step (1) is sodium hydroxide. 7 .