CN115636507B - Constructed wetland slow release filler based on sulfur autotrophic denitrification - Google Patents
Constructed wetland slow release filler based on sulfur autotrophic denitrification Download PDFInfo
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- CN115636507B CN115636507B CN202211477240.1A CN202211477240A CN115636507B CN 115636507 B CN115636507 B CN 115636507B CN 202211477240 A CN202211477240 A CN 202211477240A CN 115636507 B CN115636507 B CN 115636507B
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Abstract
The invention discloses a constructed wetland slow-release filler based on sulfur autotrophic denitrification, which consists of filler particles and sodium thiosulfate slow-release particles, wherein the filling ratio of the filler particles to the sodium thiosulfate slow-release particles is 1:0.8-1.2; the filler particles are composed of the following components: 30-50% of straw, 10-20% of calcium hydroxide, 20-40% of silicate cement and 10-20% of activated carbon. The sodium thiosulfate slow-release particles are cement slow-release particles coated with paraffin, and the cement slow-release particles are composed of the following components: 35-45% of sodium thiosulfate, 15-25% of stearic acid and 35-45% of Portland cement. The constructed wetland slow-release filler has the advantages of high removal efficiency, high mechanical strength, no need of additional carbon source, resource conservation, environmental friendliness and the like, and has good application prospects in the aspects of biological denitrification, sewage treatment and the like.
Description
Technical Field
The invention relates to a constructed wetland slow release filler based on sulfur autotrophic denitrification, belonging to the technical field of water treatment.
Background
With the rapid development of Chinese economy, the urban process is accelerated, and the discharge of domestic and industrial wastewater is continuously increased, so that the nitrogen content in the water body exceeds the standard, thereby causing the eutrophication of the water body. Eutrophication of water body can cause excessive growth of algae, reduce transparency and dissolved oxygen of water body, and even release toxic substances to destroy aquatic ecological environment. At the same time, nitrate is also converted into nitrite, which can harm human health and even induce cancer. Therefore, development of a set of denitrification treatment process which is economical, efficient and has good ecological benefits is urgent.
The existing common denitrification treatment methods include a physical method, a biological method and a chemical method. Physical denitrification methods include a gas stripping denitrification method and an ion exchange method, but the method cannot fundamentally solve the problems. The chemical denitrification method has a break point chlorination method and a magnesium ammonium phosphate precipitation method, but has high cost, can generate a large amount of byproducts and is easy to cause secondary pollution. The biological rule is to convert nitrate into nitrogen by utilizing the denitrification of microorganisms, and the method can thoroughly remove nitrate theoretically and has the advantages of high removal efficiency, low running cost and good ecological effect, so that the biological denitrification method is the most mainstream denitrification method at present.
Biological denitrification methods can be classified into autotrophic denitrification and heterotrophic denitrification according to the electron donor required by the microorganism. The wastewater in China generally has the characteristics of high nitrogen and low carbon, autotrophic denitrification is used for treating the wastewater, no external carbon source is needed, the treatment cost can be effectively reduced, the autotrophic bacteria have long growth period and low sludge yield, and the sludge treatment cost can be reduced. The sulfur autotrophic denitrification process in which a sulfur source is used as a denitrification electron donor is safer.
In biological denitrification, the traditional activated sludge process has the advantages of complex operation management, high investment and high energy consumption, so that the artificial wetland system with simple process, large buffer capacity, low operation cost and good ecological benefit is increasingly widely applied. If the constructed wetland method and the sulfur autotrophic denitrification method are combined, the advantages of the constructed wetland method and the sulfur autotrophic denitrification method can be considered. The sodium thiosulfate is easy to dissolve in water, so that the artificial wetland filler which can realize slow release of the sodium thiosulfate, can release an alkalinity substance for balancing acidity generated in the denitrification process and has porosity so as to be favorable for microorganism adhesion and has certain mechanical strength is the current research hot spot.
Disclosure of Invention
Aiming at the prior art, the invention provides the constructed wetland slow release filler based on sulfur autotrophic denitrification. The constructed wetland slow-release filler has the advantages of high removal efficiency, high mechanical strength, no need of additional carbon source, resource conservation, environmental friendliness and the like, and has good application prospects in the aspects of biological denitrification, sewage treatment and the like.
The invention is realized by the following technical scheme:
the constructed wetland slow release filler based on sulfur autotrophic denitrification consists of filler particles and sodium thiosulfate slow release particles, wherein the filling ratio of the filler particles to the sodium thiosulfate slow release particles is 1:0.8-1.2, and the weight ratio is calculated.
The particle diameters of the filler particles and the sodium thiosulfate slow-release particles are 4-8 mm, preferably 6mm.
The filler particles are composed of the following components: 30-50% of straw, 10-20% of calcium hydroxide, 20-40% of Portland cement and 10-20% of activated carbon in percentage by weight.
The sodium thiosulfate slow-release particles are cement slow-release particles coated with paraffin, and the cement slow-release particles are composed of the following components: 35-45% of sodium thiosulfate, 15-25% of stearic acid and 35-45% of Portland cement according to weight percentage; the paraffin accounts for 15-25% of the weight of the cement slow-release particles, and the thickness of the wrapped paraffin layer is 0.8-1.2 mm.
Further, the filler particles are prepared by the following method: mixing straw powder, calcium hydroxide, cement, active carbon and water in the material-water ratio of 1:0.8-1.2, and stirring uniformly (20-40 min) to obtain mixed slurry; pouring the mixed slurry into a spherical mold, and drying to obtain filler particles. And covering a layer of linen on the filler particles, keeping the linen moist by using a watering can, and maintaining for one week to improve the mechanical strength of the filler. The straw powder is prepared by the following steps: crushing the straw (using a crusher), and sieving with a 80-120 mesh sieve to obtain straw powder.
Further, the straw is selected from wheat straw, corn straw, sorghum straw, rice straw and the like.
Further, the sodium thiosulfate slow-release particles are prepared by the following method:
(1) Mixing stearic acid and absolute ethyl alcohol, heating to 70-80 ℃ in water bath, stirring until the stearic acid is completely melted, adding sodium thiosulfate, fully stirring to uniformly disperse the sodium thiosulfate, and naturally cooling to 30-35 ℃ in stirring until the solid is completely separated out; drying the precipitated solid (completely volatilizing absolute ethyl alcohol), and sieving with a 80-120 mesh sieve to obtain a slow-release capsule;
the weight ratio of the stearic acid, the absolute ethyl alcohol and the sodium thiosulfate is 1:1: (2-3);
(2) Mixing the slow-release capsule, cement and a proper amount of water (the ratio of the material to the water is 1:0.8-1.2) to obtain mixed slurry; pouring the mixed slurry into a spherical mold, and drying to obtain cement slow-release particles;
(3) Heating the solid paraffin to 65-75 ℃ in a water bath, soaking the cement slow-release particles in the paraffin for 5-10 seconds after the paraffin is completely melted, taking out, and cooling to room temperature to obtain the sodium thiosulfate slow-release particles coated with a layer of paraffin.
The constructed wetland slow release filler based on sulfur autotrophic denitrification is used as a filler in biological denitrification and sewage treatment.
The invention relates to a constructed wetland slow release filler based on sulfur autotrophic denitrification, which consists of filler particles and sodium thiosulfate slow release particles. When filler particles are used alone, bacterial growth rate is slow due to lack of sulfur source; when the sodium thiosulfate slow-release particles are used alone, the slow-release particles have smooth surfaces, so that the adhesion of microorganisms is not facilitated. Therefore, when the two kinds of particles are used alone, the denitrification effect is poor. The two fillers are coupled according to a certain proportion (the proportion of sodium thiosulfate and slaked lime is controlled), so that the slaked lime in the filler particles can perfectly neutralize the alkalinity of microorganisms generated by degrading sulfur sources in the sodium thiosulfate slow-release particles, thereby maintaining the neutral environment required by the growth of the microorganisms; the two complement each other and cooperate with each other.
The constructed wetland slow release filler based on sulfur autotrophic denitrification has the following beneficial effects:
(1) According to the invention, sodium thiosulfate is selected as a sulfur source providing substance, and the treatment efficiency is higher than that of the existing mainstream constructed wetland filler using sulfur as a sulfur source.
(2) According to the invention, the active carbon is added into the raw material of the constructed wetland filler, and can adsorb nitrate in water, so that the hydraulic retention time is increased, and the treatment effect is improved.
(3) The invention uses the slaked lime as an alkalinity providing substance, uses the silicate cement as a binder, has higher mechanical strength after the slaked lime and the silicate cement are mixed, and meanwhile, the silicate cement also has weak alkalinity, and can neutralize a part of acid generated by sulfur autotrophic denitrification. And calcium ions can be combined with phosphate radical in water to form insoluble substances, so that the filler has the function of dephosphorization.
(4) Sintering-free, low-carbon and environment-friendly.
(5) According to the invention, the straw is added into the raw material of the constructed wetland filler, so that the filler can be made to be porous, the biological attachment area is increased, a carbon source can be released, the efficiency of autotrophic heterotrophic denitrification of sulfur is improved, and a new way for utilizing the straw is increased.
Drawings
Fig. 1: photograph of filler particles.
Fig. 2: photograph of sodium thiosulfate slow-release particles.
Fig. 3: and a comparison graph of the slow release performance of slow release particles prepared by different slow release processes.
Fig. 4: schematic of nitrogen nitrate removal rate for continuous experiments.
Detailed Description
The invention is further illustrated below with reference to examples. However, the scope of the present invention is not limited to the following examples. Those skilled in the art will appreciate that various changes and modifications can be made to the invention without departing from the spirit and scope thereof.
The instruments, reagents and materials used in the examples below are conventional instruments, reagents and materials known in the art and are commercially available. The experimental methods, detection methods, and the like in the examples described below are conventional experimental methods and detection methods known in the prior art unless otherwise specified.
The cement used in the present invention was Portland cement purchased from po42.5 of the mountain and water group. The activated carbon used in the invention is purchased from Kangde brand powder activated carbon. The straw adopted by the invention is wheat straw.
Example 1 constructed wetland slow release filler based on sulfur autotrophic denitrification
The composite material consists of filler particles and sodium thiosulfate slow-release particles, wherein the filling ratio of the filler particles to the sodium thiosulfate slow-release particles is 1:1, and the weight ratio is calculated. The particle diameters of the filler particles and the sodium thiosulfate slow-release particles are 6mm.
The preparation method comprises the following steps:
(one) preparing filler particles:
(1) Crushing the straw in a crusher for 5min, and screening out straw powder by a 100-mesh screen for later use;
(2) Mixing 40 g straw powder, 15 g slaked lime, 30 g cement, 15 g activated carbon and 100 ml water, and stirring for 30 minutes to obtain mixed slurry; the mixed slurry was poured into a spherical mold (diameter 6 mm) and dried to obtain filler particles. Covering a layer of linen on the filler particles, and keeping the linen moist by using a watering can for a week. As shown in FIG. 1, the photo of the obtained filler particles was examined, and the specific surface area was 0.0048 square meters per gram, the porosity was 47%, the particle diameter was 6mm, the density was 0.78g/cm, and the bulk density was 0.368 g/cm.
(II) preparing sodium thiosulfate slow-release particles:
(1) Putting 20 g stearic acid into a beaker, adding 20 ml absolute ethyl alcohol, heating the water bath of a constant-temperature water bath to 75 ℃, stirring until the stearic acid is completely melted, adding 40 g sodium thiosulfate, fully stirring to uniformly disperse the stearic acid, and naturally cooling to 30 ℃ during stirring until the solid is completely separated out; drying the precipitated solid in a baking oven (40 ℃), and sieving with a 100-mesh sieve to obtain a slow-release capsule;
(2) Mixing the 60 g slow release capsules, 40 g cement and 100 ml water, and uniformly stirring to obtain mixed slurry; pouring the mixed slurry into a spherical mold (diameter of 6 mm), and drying to obtain cement slow-release particles;
(3) 20 g solid paraffin, heating to 70 ℃ in a water bath of a constant-temperature water bath, soaking the cement slow-release particles in the paraffin for 8 seconds after the paraffin is completely melted, taking out, cooling to room temperature, and obtaining sodium thiosulfate slow-release particles (the thickness of a paraffin layer is about 1.0 mm) with a layer of paraffin wrapped on the surface (calculated that the weight of the wrapped paraffin is 18% of that of the cement slow-release particles, 20 g paraffin is adopted here, and the cement slow-release particles can be completely wrapped by the melted paraffin), wherein a photo is shown in fig. 2.
Control 1: the slow release granule (paraffin cement for short) prepared by paraffin cement is prepared by the same method as the above (II), and the difference is that: the step (1) is not carried out, and sodium thiosulfate is adopted to replace the slow-release capsule in the step (2).
Control 2: the slow release granule (stearic acid and cement for short) prepared by adding the stearic acid and the cement is prepared by the same method as the (II) above, and the difference is that: and (3) not carrying out the step (3), wherein the cement slow-release particles obtained in the step (2) are the final product.
Two sodium thiosulfate slow-release particles prepared above were taken and immersed in 250 ml water, and the slow-release rates thereof are shown in table 1. Meanwhile, the controlled release granules prepared by adding cement into paraffin and the controlled release granules prepared by adding cement into stearic acid are used as controls, and the results are shown in figure 3. As can be seen from table 1 and fig. 3, the sodium thiosulfate slow-release particles of the present invention have good slow-release effect; when paraffin or stearic acid is not added, the slow release effect is obviously different.
TABLE 1
Filling the prepared filler particles and sodium thiosulfate slow-release particles into an up-flow anaerobic sludge reactor (the filling weight ratio of the filler particles to the sodium thiosulfate slow-release particles is 1:1), and carrying out stable and continuous water inlet by a peristaltic pump, wherein the HRT is 9.6h, and the nitrate nitrogen concentration of the water inlet is 130mg/L. The nitrate nitrogen removal efficiency is shown in table 2 and fig. 4. As can be seen from table 2 and fig. 4, the constructed wetland slow release filler based on sulfur autotrophic denitrification has good denitrification effect.
TABLE 2
The foregoing examples are provided to fully disclose and describe how to make and use the claimed embodiments by those skilled in the art, and are not intended to limit the scope of the disclosure herein. Modifications that are obvious to a person skilled in the art will be within the scope of the appended claims.
Claims (7)
1. An artificial wetland slow release filler based on sulfur autotrophic denitrification is characterized in that: the composite material consists of filler particles and sodium thiosulfate slow-release particles, wherein the filling ratio of the filler particles to the sodium thiosulfate slow-release particles is 1:0.8-1.2, and the weight ratio is calculated;
the particle size of the filler particles and the sodium thiosulfate slow-release particles is 4-8 mm;
the filler particles are composed of the following components: 30-50% of straw, 10-20% of calcium hydroxide, 20-40% of Portland cement and 10-20% of activated carbon in percentage by weight;
the sodium thiosulfate slow-release particles are cement slow-release particles coated with paraffin, and the cement slow-release particles are composed of the following components: 35-45% of sodium thiosulfate, 15-25% of stearic acid and 35-45% of Portland cement according to weight percentage; the paraffin accounts for 15-25% of the weight of the cement slow-release particles, and the thickness of the wrapped paraffin layer is 0.8-1.2 mm;
the sodium thiosulfate slow-release particles are prepared by the following method:
(1) Mixing stearic acid and absolute ethyl alcohol, heating water to 70-80 ℃, stirring until the stearic acid is completely melted, adding sodium thiosulfate, fully stirring to uniformly disperse the sodium thiosulfate, and naturally cooling to 30-35 ℃ during stirring until the solid is completely separated out; drying the precipitated solid to obtain a slow-release capsule; the weight ratio of the stearic acid, the absolute ethyl alcohol and the sodium thiosulfate is 1:1: (2-3);
(2) Mixing the slow-release capsule, cement and a proper amount of water to obtain mixed slurry; pouring the mixed slurry into a spherical mold, and drying to obtain cement slow-release particles;
(3) Heating the solid paraffin to 65-75 ℃, soaking the cement slow-release particles in the paraffin after the paraffin is completely melted for 5-10 seconds, taking out, and cooling to room temperature to obtain sodium thiosulfate slow-release particles coated with a layer of paraffin;
the straw is selected from wheat straw, corn straw, sorghum straw and rice straw.
2. The slow release filler for constructed wetlands based on sulfur autotrophic denitrification according to claim 1, wherein the filler particles are composed of: 40% of straw, 15% of calcium hydroxide, 30% of silicate cement and 15% of activated carbon.
3. The constructed wetland slow release filler based on sulfur autotrophic denitrification as claimed in claim 1, wherein the constructed wetland slow release filler is characterized in that: the cement slow-release particles are composed of the following components: 40% of sodium thiosulfate, 20% of stearic acid and 40% of Portland cement; the thickness of the wrapped paraffin layer is 1.0mm.
4. The slow release filler for constructed wetlands based on sulfur autotrophic denitrification according to claim 1, wherein the filler particles are prepared by the following method: mixing straw, calcium hydroxide, cement, active carbon and water in the material-water ratio of 1:0.8-1.2, and stirring uniformly to obtain mixed slurry; pouring the mixed slurry into a spherical mold, and drying to obtain filler particles.
5. The constructed wetland slow release filler based on sulfur autotrophic denitrification as claimed in claim 4, wherein the constructed wetland slow release filler is characterized in that: covering a layer of linen on the filler particles, and keeping the linen moist by using a watering can for a week.
6. The constructed wetland slow release filler based on sulfur autotrophic denitrification as claimed in claim 1, wherein the constructed wetland slow release filler is characterized in that: the filling ratio of the filler particles to the sodium thiosulfate slow-release particles is 1:1; the particle diameters of the filler particles and the sodium thiosulfate slow-release particles are 6mm.
7. The use of the constructed wetland slow release filler based on sulfur autotrophic denitrification as defined in any one of claims 1 to 6 in biological denitrification and sewage treatment.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20050032269A (en) * | 2003-10-01 | 2005-04-07 | 광주과학기술원 | Method of high-rate denitrification using two reactors in series |
| CN104591384A (en) * | 2015-01-31 | 2015-05-06 | 淄博正邦知识产权企划有限公司 | Slow-release sewage processing material and preparation method thereof |
| CN107522286A (en) * | 2017-10-17 | 2017-12-29 | 浙江深德环境技术有限公司 | A kind of tail water processing method based on sulphur/oyster shell |
| CN109650539A (en) * | 2019-02-21 | 2019-04-19 | 天津友爱环保科技有限公司 | Biologic packing material and its preparation method and application for removing groundwater azotate |
| CN114524513A (en) * | 2022-01-28 | 2022-05-24 | 大连理工大学 | Method for treating low C/N sewage by anaerobic-aerobic-anoxic-moving bed autotrophic denitrification process |
| CN114524511A (en) * | 2022-01-28 | 2022-05-24 | 大连理工大学 | Alkalinity slow-release porous spherical shell suspended filler based on sulfur autotrophic nitrogen removal of low C/N sewage |
-
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- 2022-11-23 CN CN202211477240.1A patent/CN115636507B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20050032269A (en) * | 2003-10-01 | 2005-04-07 | 광주과학기술원 | Method of high-rate denitrification using two reactors in series |
| CN104591384A (en) * | 2015-01-31 | 2015-05-06 | 淄博正邦知识产权企划有限公司 | Slow-release sewage processing material and preparation method thereof |
| CN107522286A (en) * | 2017-10-17 | 2017-12-29 | 浙江深德环境技术有限公司 | A kind of tail water processing method based on sulphur/oyster shell |
| CN109650539A (en) * | 2019-02-21 | 2019-04-19 | 天津友爱环保科技有限公司 | Biologic packing material and its preparation method and application for removing groundwater azotate |
| CN114524513A (en) * | 2022-01-28 | 2022-05-24 | 大连理工大学 | Method for treating low C/N sewage by anaerobic-aerobic-anoxic-moving bed autotrophic denitrification process |
| CN114524511A (en) * | 2022-01-28 | 2022-05-24 | 大连理工大学 | Alkalinity slow-release porous spherical shell suspended filler based on sulfur autotrophic nitrogen removal of low C/N sewage |
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