CN116002871A - Reinforced denitrification filler and preparation method and application thereof - Google Patents

Abstract

The invention discloses an enhanced denitrification filler and a preparation method thereof, comprising: (1) heating and melting sulfur and pumping it into a reaction kettle; (2) adding biomass powder and volcanic rock powder into the reaction kettle, stirring evenly, and cooling to produce In the described enhanced denitrification filler, the mass percent of each component is: 50-80% of sulfur, 15-40% of biomass, and 10-30% of volcanic rock. The invention also discloses the application of the enhanced denitrification filler in sewage denitrification. The enhanced denitrification filler prepared by the invention can stabilize the pH of the system, reduce the consumption of sulfur and the production of sulfate, and avoid secondary pollution; the enhanced denitrification filler prepared by the invention has high mechanical strength and long service life; The enhanced denitrification filler can be efficiently used in the anoxic or anaerobic tank of the rural domestic sewage reaction device, which can significantly improve the denitrification effect of the device.

Description

A kind of enhanced denitrification filler and its preparation method and application

technical field

The invention relates to the technical field of sewage treatment, in particular to an enhanced denitrification filler and its preparation method and application.

Background technique

Rural environmental governance has received more and more attention in recent years, especially water environment governance is the most prominent and sensitive. Due to the difficulties in guaranteeing funds for construction, operation and maintenance, lack of professional and technical personnel, and improper selection of treatment processes, the treatment of rural domestic sewage has become a prominent shortcoming in the current improvement of the rural living environment. In particular, the sewage treatment technology for water quality-sensitive areas with high requirements for total nitrogen removal is still relatively lacking.

Conventional biological methods use nitrification and denitrification to remove total nitrogen, nitrification under aerobic conditions, denitrification under anoxic and anaerobic conditions, and microorganisms in the denitrification stage need to consume a large amount of organic matter. At present, the rural domestic sewage treatment processes and devices used in my country are basically reduced versions of urban domestic sewage treatment processes and devices. For example, AAO, AO and other processes and devices commonly used in urban domestic sewage treatment are often used in rural domestic sewage treatment. application. However, rural domestic sewage has the characteristics of large fluctuations in water quality, less carbon sources, and low carbon-nitrogen (C/N) ratios. For domestic sewage with a low C/N ratio, to achieve enhanced denitrification through nitrification and denitrification, it is often necessary to add additional carbon sources, or to achieve short-range nitrification and denitrification, anaerobic ammonium oxidation and other new technologies through highly automated control and refined management. Nitrogen removal using advanced nitrogen removal technology requires complex system maintenance and management, high precision, and high cost, making it difficult to promote in rural areas. For the AAO and AO processes that have been widely used in rural areas, how to improve their denitrification performance through simple methods is the key.

Biological denitrification can be divided into heterotrophic denitrification and autotrophic denitrification technology. Autotrophic denitrification technology has gradually become a popular technology due to its advantages of not needing to add organic carbon source, reducing sludge production and improving denitrification efficiency. The main research direction of the new biological denitrification process.

Sulfur autotrophic denitrification technology uses sulfur as an electron donor to convert nitrate nitrogen into nitrogen gas under the action of sulfur autotrophic microorganisms to complete the denitrification process. This process does not require an external organic carbon source, which can save operating costs and reduce sludge production. However, the reaction process consumes alkalinity, which easily reduces the pH of the system. Generally, alkalinity needs to be supplemented, and elemental sulfur is easy to lose. Using it alone may cause problems such as excessive sulfate content.

Therefore, it is the key to the friendly utilization of sulfur autotrophic denitrification technology to develop an enhanced denitrification-type sulfur-containing filler that is suitable for the utilization of biological pools and avoids secondary pollution. And recent studies have shown that the synergistic denitrification effect of autotrophic and heterotrophic is better than that of autotrophic denitrification alone.

Contents of the invention

The invention provides an enhanced denitrification filler and a preparation method thereof. The enhanced denitrification filler is beneficial to pH adjustment during the denitrification process, reduces sulfur consumption, reduces sulfate production, and avoids secondary pollution.

Technical scheme of the present invention is as follows:

A method for preparing an enhanced denitrification filler, comprising:

(1) Sulfur is heated and melted and then pumped into the reactor;

(2) Adding biomass powder and volcanic rock powder to the reaction kettle, stirring evenly, cooling and granulating to obtain a strengthened denitrification filler;

In the enhanced denitrification filler, the mass percentages of each component are: 50-80% of sulfur, 15-40% of biomass, and 10-30% of volcanic rock.

Volcanic rocks are rich in dozens of minerals and trace elements such as sodium, magnesium, aluminum, silicon, calcium, titanium, manganese, iron, phosphorus, nickel, cobalt and molybdenum, which can stabilize mineral content, and volcanic rocks can release minerals The dual characteristics of elements and absorption of impurities in water provide nutrients for the growth of microorganisms, which is beneficial to the growth of microorganisms, shortens the start-up time of the denitrification reaction device, and provides minerals and trace elements for the growth and metabolism of microorganisms.

The high surface area produced by the porosity of volcanic rocks is a good hotbed for cultivating microorganisms in water, and the positive charge on the surface is conducive to the growth of microorganisms. With strong hydrophilicity, volcanic rocks provide ideal attachment sites for microorganisms while adsorbing pollutants, which is beneficial to Degradation of pollutants.

In addition, during the denitrification process, volcanic rock can stabilize the pH of the system, and can properly adjust the water that is too acidic or too alkaline to be close to neutral, which is beneficial to neutralize the acid produced by sulfur autotrophic denitrification.

Preferably, the particle size of the volcanic rock powder is 40-60 mesh.

In the enhanced denitrification filler, sulfur and biomass form an autotrophic and heterotrophic synergistic denitrification reaction system, which is beneficial to the denitrification of wastewater with low carbon-to-nitrogen ratio and high nitrogen, and the addition of biomass can share the denitrification of sulfur Pressure is conducive to the adjustment of pH, reducing the consumption of sulfur, reducing the production of sulfate, and avoiding secondary pollution.

Preferably, the particle size of the biomass powder is 40-300 mesh.

Powdered biomass is larger than the surface area, which is more conducive to microbial utilization.

Preferably, the biomass is rice bran; the rice bran is a mixture of rice husk and rice husk; in the rice bran, the mass fraction of rice husk is 70-90%, and the mass fraction of rice husk is 10-30%.

The rice bran composed of rice husk and rice skin contains micronutrients such as vitamins, which is conducive to the attachment and growth of microorganisms, and the prepared filler shortens the film-hanging time in the reactor.

Preferably, the particle size of the enhanced denitrification filler is 6-9 mm.

Preferably, in step (1), the heating and melting temperature is 115-120°C.

Preferably, in step (2), before adding biomass powder and volcanic rock powder, the reactor is heated to 135-200°C.

Through melting sulfur, and then at a higher temperature of the reactor, adding biomass, volcanic rock and molten sulfur to mix and then quickly cooling and granulating can effectively improve the mechanical strength of the particles. The filler will not disperse in water for a long time without adding binders. , Foaming agent, increase the effective denitrification ingredients of the filler, and improve the service life of the filler.

Biomass is partially carbonized at a high temperature of 135-200°C. The functional group redox and electrical conductivity of biomass charcoal, as well as its high specific surface area biological activity, can promote the attachment and growth of microorganisms, and promote the interaction between fillers, microorganisms and pollutants. Electron transfer improves the denitrification performance of the filler.

Further, in step (2), before adding biomass powder and volcanic rock powder, the reactor is heated to 135-180°C.

If the temperature of the reaction kettle is too high, such as exceeding 180°C, the denitrification effect of the prepared packing will decrease.

The present invention also provides an enhanced denitrification filler prepared by the method.

The present invention also provides the application of the above-mentioned enhanced denitrification filler in sewage denitrification, including:

Mix the enhanced denitrification filler with polyurethane sponge filler, and put it into a hollow suspension ball to make a composite suspension filler;

Put the composite hanging filler into the anoxic tank or anaerobic tank, and the filling rate of the hanging filler is 50-80%.

The denitrification filler of the present invention can be used in anoxic ponds or anaerobic ponds, aiming at the characteristics of low carbon-to-nitrogen ratio and high nitrogen content of rural domestic sewage, while strengthening the denitrification effect, the pH of sewage is basically maintained at neutral, and there is It is conducive to the growth of microbial film, can make full use of the organic matter in the sewage, and the autotrophic and heterotrophic synergistic denitrification greatly improves the impact load resistance of the device.

The enhanced denitrification filler of the present invention can not only be used in new AO and AAO treatment devices for rural domestic sewage, but also can be used for quality improvement of a large number of existing rural domestic sewage treatment devices, greatly improving the compliance rate of effluent water quality such as total nitrogen in the device .

Compared with prior art, the beneficial effect of the present invention is:

The enhanced denitrification filler prepared by the invention can stabilize the pH of the system, reduce the consumption of sulfur and the production of sulfate, and avoid secondary pollution; the enhanced denitrification filler prepared by the invention has high mechanical strength and long service life; The enhanced denitrification filler can be efficiently used in the anoxic or anaerobic tank of the rural domestic sewage reaction device, which can significantly improve the denitrification effect of the device.

Description of drawings

Figure 1 shows the water quality of total nitrogen inflow and outflow in Application Example 1 and Application Comparative Example 1.

Detailed ways

In Examples 1-9, the rice bran is a mixture of rice husk powder and rice bran with a mass fraction of 80%:20%.

Example 1

Filling 1: Sulfur with a purity greater than 99% is heated to 120°C in the sulfur melting kettle 1 to melt, and then pumped into the reaction kettle 2 after melting into a liquid. After 3 hours, it is pumped into the granulation equipment and cooled by circulating cooling water to form granules with a particle size of 6-9mm. The mass percent of each component: sulfur is 60%, rice bran is 20%, and volcanic rock is 20%.

The mass ratio of sulfur: rice bran: volcanic rock is 3:1:1.

Example 2

Filler 2: Sulfur with a purity greater than 99% is heated to 120°C in the sulfur melting kettle 1 to melt, and then pumped into the reaction kettle 2 after melting into a liquid. After 3 hours, it is pumped into the granulation equipment and cooled by circulating cooling water to form granules with a particle size of 6-9mm. The mass percent of each component: sulfur is 60%, rice bran is 20%, and volcanic rock is 20%.

Example 3

Filler 3: Sulfur powder with a purity greater than 99%, 80-mesh rice bran, and 40-mesh volcanic rock powder are mixed and heated to 120°C in the sulfur melting kettle 1, and then stirred for 3 hours, then pumped into the granulation equipment and cooled by circulating cooling water for granulation Shaped into a spherical shape with a particle size of 6-9mm. The mass percent of each component: sulfur is 60%, biomass is 20%, and volcanic rock is 20%.

Comparative example 1

Filler 4: 6-9mm sulfur particles with a purity greater than 99%, 80-mesh rice bran, and 40-mesh volcanic rock powder are mixed evenly at room temperature, and the mass percentages of each component are: 60% sulfur, 20% rice bran, and 20% volcanic rock.

Comparative example 2

Filler 5: Sulfur with a purity greater than 99% is heated to 120°C in the sulfur melting kettle 1 to melt, and then pumped into the reaction kettle 2 after melting into a liquid. The granulation equipment is cooled by circulating cooling water and granulated into spherical shapes with a particle size of 6-9mm.

The mass ratio of sulfur: rice bran is 3:1. Comparing filler 4 with filler 1, only volcanic rock is not added, and everything else is the same.

Comparative example 3

Filler 6: Sulfur with a purity greater than 99% is heated to 120°C in the sulfur melting kettle 1 to melt, and then pumped into the reactor 2 after melting into a liquid. The temperature of the reactor 2 is 150°C. Into the granulation equipment, the granulation is cooled by circulating cooling water and formed into a spherical shape with a particle size of 6-9mm.

The mass ratio of sulfur to volcanic rock is 3:1. Compared with filler 1, filler 5 does not add rice bran, and everything else is the same.

Comparative example 4

Filler 7: granular sulfur with a particle size of 6-9mm (purity of sulfur is greater than 99%).

Comparative example 5

Filler 8: 40 mesh volcanic rock.

Comparative example 6

Filler 9: rice bran of 80 mesh.

Nitrogen removal test 1

In 9 anaerobic bottles of 250mL, add 9 kinds of fillers prepared by Examples 1-3 and Comparative Examples 1-6 respectively, and the weight is 5g, and inoculate the autotrophic sludge acclimated in the above 9 anaerobic bottles 5ml, 5ml of anaerobic tank sludge from a domestic sewage treatment plant, add 200ml of artificially prepared nitrate-containing wastewater, and place it on an air bath shaker with a shaker speed of 120 rpm and a temperature of 25°C. During the culture period, every 24 hours, take out the anaerobic bottle, let it stand for 40 minutes, pour off the supernatant, and then add 200ml of new water. After 12 days of continuous culture and film formation, after 3 days of stabilization, the water distribution time was changed every 24 hours, and the water quality after treatment in 9 anaerobic bottles was measured.

Artificial water distribution: glucose 120mg/L, sodium nitrate 364.3mg/L (total nitrogen 60mg/L), potassium dihydrogen phosphate 21.9mg/L (total phosphorus 5mg/L), magnesium sulfate heptahydrate 10mg/L, dihydrate chloride Calcium 5mg/L, use tap water to mix water, adjust influent pH to 7.0, artificial water C/N ratio is 2:1, SO ₄ ^2- 72.4mg/L. The distribution water was filled with nitrogen gas for 30 minutes before adding to the anaerobic bottle.

The results are shown in Table 1:

Table 1 Water quality after treatment with 9 kinds of fillers (initial total nitrogen 60mg/L, total phosphorus 5mg/L)

The above results show that the filler prepared by sulfur + rice bran + volcanic rock has excellent denitrification performance, and the removal effect is greater than the sum of the denitrification of the fillers prepared by sulfur + rice bran and sulfur + volcanic rock respectively, indicating that the sulfur + rice bran + volcanic rock prepared enhanced denitrification The materials have the effect of synergistic denitrification among each other, and denitrification is carried out efficiently under the synergistic effect of autotrophy and heterotrophy. During the denitrification process, there is basically no accumulation of nitrite. And the filler made of sulfur + rice bran + volcanic rock, after denitrification treatment, the pH is basically neutral.

The comparison of the removal effects of filler 1 and filler 3 shows that the sulfur is melted first, and then mixed with rice bran and volcanic rock in a reactor at a higher temperature (135-180°C), and then granulated with circulating cooling water. Compared with the filler prepared by low-temperature melting granulation, the denitrification effect is better. However, if the temperature is too high, such as exceeding 180°C, the denitrification effect of the prepared filler will decrease. For example, the denitrification effect of filler 2 is worse than that of filler 1.

The comparison of the denitrification effects of filler 1 and filler 4 shows that the denitrification effect of the enhanced denitrification filler prepared by the present invention is better than that of the mixture of individual materials, and the sulfate concentration produced is lower.

Application example 1

An anoxic-aerobic (AO) process rural domestic sewage treatment plant with a design flow rate of 1t/d, add suspension filler made of composite filler balls in the anoxic tank, the composite filler balls contain filler 1 and polyurethane sponge, filler 1 The volume ratio of polyurethane sponge filler is 2:1, and the filling rate of hanging filler is 70%.

The device reflux ratio is 3:1. The aerobic pool contains polyurethane sponge suspension filler with a filling rate of 50%. The flow rate of the aeration pump in the aerobic pool is 50L/min.

After hanging fillers in the anoxic pool, insert 3L of domesticated autotrophic sludge and 3L of sludge from the anaerobic pool of domestic sewage treatment plant into the anoxic pool. Inoculate 3L of aerobic pool sludge from the domestic sewage treatment plant into the aerobic pool, and the influent flow rate during the film formation stage is 0.5t/d.

After 9 days of filming, the removal of total nitrogen in the effluent was stable, the influent flow rate was adjusted to 1t/d, and a continuous water flow test was carried out. The system began to collect influent and effluent data 15 days after the filming, and the data was collected every one week.

Influent concentration, COD: 72～152mg/L, ammonia nitrogen: 48.8～71.1mg/L, total nitrogen 54.5～74.8mg/L, pH6.8-7.5

Effluent COD: 31~38mg/L, ammonia nitrogen: 0.213-1.28mg/L, pH 6.85-7.6mg/L. The total nitrogen in the influent and effluent is shown in Figure 1. The total nitrogen in the effluent is 9.8-14.8mg/L, and the average removal rate of total nitrogen is 81.8%.

Application Comparative Example 1

The designed flow rate is 1t/d for an anoxic-aerobic (AO) process rural domestic sewage treatment plant. Add suspension filler made of composite filler balls to the anoxic pool. The composite filler balls contain polyurethane sponge, and the filling rate of the suspension filler is 70%.

The device reflux ratio is 3:1. The aerobic pool contains polyurethane sponge suspension filler with a filling rate of 50%. The flow rate of the aeration pump in the aerobic pool is 50L/min.

After the suspension filler is hung in the anoxic tank, the mixed sludge of 3L domesticated autotrophic sludge and 3L sludge of the anaerobic tank of the domestic sewage treatment plant is inserted into the anoxic tank. Inoculate 3L of aerobic pool sludge from the domestic sewage treatment plant into the aerobic pool, and the influent flow rate during the film formation stage is 0.5t/d.

After 15 days of film formation, the removal of total nitrogen in the effluent was stable, the influent flow rate was adjusted to 1t/d, and a continuous water flow test was carried out. The water inflow and outflow data will be systematically collected 15 days after the film is installed, and the data will be collected every one week.

Influent concentration, COD: 72～152mg/L, ammonia nitrogen: 48.8～71.1mg/L, total nitrogen 54.5～74.8mg/L, pH6.8-7.5

Effluent COD: 32-43mg/L, ammonia nitrogen: 0.267-7.96mg/L, pH 6.9-7.6mg/L.

The total nitrogen in the influent and effluent is shown in Figure 1. The total nitrogen in the effluent is 47-65.9mg/L, and the average removal rate of total nitrogen is 18.6%.

Compared with application example 1 and application comparison example 1, the water inflow is the same. Application example 1 uses filler 1 prepared from sulfur, biomass, and volcanic rock in the anoxic pool. Application example 1 uses ordinary sponge filler, and the rest are the same. From application example 1 and application comparison example 1, it can be known that the use of filler 1 can effectively shorten the start-up time of the device for film formation. The device has been in operation for more than 3 months, and the denitrification effect of application example 1 is significantly higher than that of application comparison example 1. It shows that the filler prepared by the invention can be efficiently used in the anoxic or anaerobic tank of the rural domestic sewage reaction device, and can significantly improve the denitrification effect of the device.

The embodiments described above have described the technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. All within the scope of the principles of the present invention Any modifications, supplements and equivalent replacements should be included within the protection scope of the present invention.

Claims (9)

1. A preparation method for strengthening denitrification filler, characterized in that, comprising: (1) Sulfur is heated and melted and then pumped into the reactor; (2) Adding biomass powder and volcanic rock powder to the reaction kettle, stirring evenly, cooling and granulating to obtain a strengthened denitrification filler; In the enhanced denitrification filler, the mass percentages of each component are: 50-80% of sulfur, 15-40% of biomass, and 10-30% of volcanic rock. 2. The preparation method of the enhanced denitrification filler according to claim 1, characterized in that the particle size of the volcanic rock powder is 40-60 mesh. 3. The preparation method of the enhanced denitrification filler according to claim 1, characterized in that, the particle size of the biomass powder is 40-300 mesh. 4. The preparation method of the enhanced denitrification filler according to claim 1, wherein the biomass is rice bran; the rice bran is a mixture of rice husk and rice bran; in the rice bran, the mass fraction of rice husk It is 70-90%, and the mass fraction of rice skin is 10-30%. 5. The preparation method of the enhanced denitrification filler according to claim 1, characterized in that the particle size of the enhanced denitrification filler is 6-9 mm. 6. The preparation method of the enhanced denitrification filler according to claim 1, characterized in that, in step (1), the heating and melting temperature is 115-120°C. 7. The preparation method of the enhanced denitrification filler according to claim 1 or 6, characterized in that, in step (2), before adding biomass powder and volcanic rock powder, the reactor is heated to 135-200°C. 8. An enhanced denitrification filler, characterized in that it is prepared by the preparation method according to any one of claims 1-7. 9. An application of the enhanced denitrification filler as claimed in claim 8 in sewage denitrification, characterized in that it comprises: Mix the enhanced denitrification filler with polyurethane sponge filler, and put it into a hollow suspension ball to make a composite suspension filler; Put the composite hanging filler into the anoxic tank or anaerobic tank, and the filling rate of the hanging filler is 50-80%.

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