CN109179688B - Denitrification carbon source and preparation method thereof - Google Patents

Abstract

The invention provides a denitrification carbon source, and belongs to the field of water treatment. The invention adopts the kitchen waste oil as the raw material main body of the denitrification carbon source layer, is easy to obtain, has low cost and obvious price advantage, solves the treatment problem of the kitchen waste oil, treats the sewage by the waste, provides carbon source supplement in the sewage biological treatment process, strengthens the biological treatment effect and improves the effluent quality; the structure of the water-based polyurethane coating is adopted to wrap the inner denitrification carbon source layer, and the surface of the denitrification carbon source layer is wrapped with the semi-permeable or impermeable substance, so that the denitrification carbon source is slowly released through micropores and gaps of the coating and is utilized by microorganisms, the utilization rate and the denitrification efficiency of the denitrification carbon source are improved, the coating layer is harmless to the microorganisms, the environment is protected, the structure is stable, and the problems that other denitrification carbon source fillers are consumed by the microorganisms and need to be replaced regularly are solved. Meanwhile, the denitrification carbon source layer provided by the invention has certain alkalinity.

Description

A kind of denitrifying carbon source and preparation method thereof

technical field

The invention relates to the technical field of water treatment, in particular to a denitrifying carbon source and a preparation method thereof.

Background technique

At present, the problem of nitrogen pollution in water bodies in my country is very serious. According to the survey, the sewage treatment plant can easily convert ammonia nitrogen into nitrate nitrogen, and ammonia nitrogen can easily meet the emission standard. However, due to the lack of carbon source, the C/N value is low, and the denitrification process generally has the problem of insufficient carbon source, which seriously restricts The ability of nitrate nitrogen to be converted into nitrogen by denitrification affects the denitrification efficiency, making it difficult for total nitrogen to meet emission standards.

In order to achieve the desired denitrification effect, it is often necessary to add a carbon source to the denitrification reactor. Traditionally added solid carbon sources include sodium acetate and glucose, and liquid carbon sources such as methanol and ethanol. Sodium acetate and glucose have high cost and large dosage, which increases operating cost. Methanol and ethanol not only cause high operating costs, but also such carbon sources are explosive and flammable substances, which have certain safety hazards. In order to solve the above problems, in recent years, people have devoted themselves to the development of some new carbon sources, looking for non-toxic and cheap external carbon sources to replace traditional carbon sources. Polymers, primary sludge hydrolyzates and industrial wastewater, etc., but their carbon release rate is unstable, which is easy to cause carbon source loss, and will increase the organic carbon content in the water, the water quality fluctuates greatly, and the effluent effect is not ideal, such as China Patent CN201510316217.8 discloses that rice husk and lychee core are made into solid carbon source, and rice husk powder is released as carbon source, but the carbon source is mainly cellulose, which has low bioavailability, unstable treatment effect, and large fluctuation of water quality. .

In order to solve the problem of carbon source release rate, people began to study the denitrifying carbon source technology, most of which are to wrap the carbon source on the substrate skeleton carrier or use the wrapping method to prepare the denitrifying carbon source, such as Chinese patent CN201710960257. Sodium is encapsulated in chitosan capsules as a denitrifying carbon source, but after soaking in water, chitosan will gradually dissolve, and the carbon source in the capsules will be released in large quantities, which will increase the COD value in the water and affect the water quality; Chinese patent CN201711392022 .7 discloses that the slow-release carbon source filler is composed of an external carbon source layer, an internal carbon source layer and a connecting colloid, the external carbon source is made into powder, and the internal carbon source is wrapped in multiple layers through the connecting colloid, and the outer layer is mainly composed of For degradable polymers, when the polymer is degraded, a large amount of internal carbon sources will be released, resulting in changes in the rate of carbon release and fluctuations in water quality.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a denitrifying carbon source and a preparation method thereof. The invention uses the kitchen waste oil to prepare the denitrifying carbon source layer, which is slowly released through the micropores and gaps of the coating layer, so that the carbon source is released evenly and the rate is stable, and at the same time, the prepared denitrifying carbon source layer is alkaline. The alkalinity of water can be increased, and the problem of pH drop in the subsequent biological nitrification process can be alleviated.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

A denitrifying carbon source, comprising an inner and outer layer, the outer layer is a coating layer, the inner layer is a denitrifying carbon source layer, and the coating layer comprises the following components by weight: water-based polyurethane 20～ 30 parts, 4-6 parts of sodium alginate, 1-2 parts of foaming agent and 3-5 parts of emulsifier; the denitrifying carbon source layer is prepared from the following raw materials by weight: 40-50 parts of kitchen waste oil parts, 4-6 parts of sodium hydroxide, 16-20 parts of water, 6 parts of 95% ethanol, 2-4 parts of polylactic acid powder, 0.05-0.1 part of curing agent, 0.5-1 part of structural stabilizer and 0.5-1 part of reinforcing agent 2 servings.

Preferably, the mass ratio of the inner layer to the outer layer is 10:2-3.

Preferably, the blowing agent is inorganic fibers, azodicarbonamide, alum or organic polymers.

Preferably, the emulsifier is propylene glycol fatty acid ester or lauric acid monoglyceride.

Preferably, the curing agent is methyl ethyl ketone peroxide, the structural stabilizer is disodium EDTA, and the reinforcing agent is polypropylene staple fibers.

The present invention also provides the preparation method of the denitrifying carbon source described in the above technical solution, comprising the following steps:

The waste kitchen oil is heated, cooled and filtered in turn to obtain pretreated waste oil;

Carry out adsorption reaction with the pretreated waste oil and activated clay to obtain refined waste oil;

Carry out saponification reaction with sodium hydroxide and water after preheating the refining waste oil to obtain a saponification product;

The saponification product, ethanol, polylactic acid powder, curing agent, structural stabilizer and reinforcing agent are mixed and then granulated to obtain denitrifying carbon source particles of kitchen waste oil;

Mix sodium alginate, emulsifier and water to obtain emulsion;

Mixing the emulsion, water polyurethane and foaming agent to obtain a film-coated emulsion;

The denitrifying carbon source particles of the kitchen waste oil are coated with the coating emulsion to obtain the denitrifying carbon source.

Preferably, the mass ratio of the pretreated waste oil and activated clay is 1-2:20.

Preferably, the temperature of the adsorption reaction is 100-120° C., and the time is 30-60 min.

Preferably, the temperature of the saponification reaction is 85-90° C., and the time is 30-60 min.

Preferably, the mass ratio of the refining waste oil to sodium hydroxide is 8-12:1.

The present invention provides a denitrifying carbon source, comprising two layers: inner and outer layers, the outer layer is a coating layer, the inner layer is a denitrifying carbon source layer, and the coating layer comprises the following components in parts by weight: water-based polyurethane 20-30 parts of acid ester, 4-6 parts of sodium alginate, 1-2 parts of foaming agent and 3-5 parts of emulsifier; the denitrifying carbon source layer is prepared from raw materials including the following parts by weight: kitchen waste 40-50 parts of oil, 4-6 parts of sodium hydroxide, 16-20 parts of water, 6 parts of 95% ethanol, 2-4 parts of polylactic acid powder, 0.05-0.1 part of curing agent, 0.5-1 part of structural stabilizer and Strengthening agent 0.5 to 2 parts. The method adopts the kitchen waste oil as the main raw material of the denitrifying carbon source layer, which is easy to obtain, low in cost, and has obvious price advantages, solves the processing problem of the kitchen waste oil, and changes the problem that the kitchen waste oil harms human health and pollutes the environment. This traditional understanding, using waste to control pollution, provides carbon source supplementation in the biological sewage treatment process, strengthens the biological treatment effect, and improves the effluent quality; the structure of the water-based polyurethane coating is used to wrap the internal denitrification carbon source. The surface of the denitrifying carbon source layer wraps semi-permeable or impermeable substances on the surface of the denitrifying carbon source layer, so that the denitrifying carbon source is slowly released through the micropores and gaps of the coating, which is used by microorganisms and improves the utilization of the denitrifying carbon source. The coating layer has no harm to microorganisms, is environmentally friendly, and has a stable structure, which avoids the problem that other denitrifying carbon source fillers are consumed by microorganisms and need to be replaced regularly. At the same time, the denitrifying carbon source layer provided by the present invention has a certain degree of alkalinity, which solves the problem of the gradual drop of pH in the denitrifier, and enables the pH of the reactor to be stabilized in the optimum range for the survival of denitrifying bacteria. Additional agent is added to improve alkalinity; polylactic acid powder is added in the invention to strengthen the carbon release effect of the denitrifying carbon source, and at the same time, a reinforcing agent is added to improve the mechanical strength of the denitrifying carbon source. The data of the examples show that the pH value of the denitrifying carbon source provided by the present invention is alkaline, the pH of the effluent is stable, and the quality of the effluent is good.

Detailed ways

The present invention provides a denitrifying carbon source, comprising two layers: inner and outer layers, the outer layer is a coating layer, the inner layer is a denitrifying carbon source layer, and the coating layer comprises the following components in parts by weight: water-based polyurethane 20-30 parts of acid ester, 4-6 parts of sodium alginate, 1-2 parts of foaming agent and 3-5 parts of emulsifier; the denitrifying carbon source layer is prepared from raw materials including the following parts by weight: kitchen waste 40-50 parts of oil, 4-6 parts of sodium hydroxide, 16-20 parts of water, 6 parts of 95% ethanol, 2-4 parts of polylactic acid powder, 0.05-0.1 part of curing agent, 0.5-1 part of structural stabilizer and Strengthening agent 0.5 to 2 parts.

In the present invention, the mass ratio of the inner layer to the outer layer is preferably 10:2-3.

In the present invention, the coating layer preferably includes the following components in parts by weight: 30 parts of aqueous polyurethane, 6 parts of sodium alginate, 2 parts of foaming agent and 4 parts of emulsifier. The present invention adopts the structure of water-based polyurethane coating, wraps the inner denitrifying carbon source layer, and wraps semi-permeable or water-impermeable substances on the surface of the denitrifying carbon source layer, so that the denitrifying carbon source passes through the coated micro-organisms. The pores and gaps are slowly released and used by microorganisms, which improves the utilization rate of denitrifying carbon sources and the denitrification efficiency, and the coating layer is harmless to microorganisms, environmentally friendly, and has a stable structure, avoiding other denitrifying carbon source fillers. The problem of microbial consumption and the need for regular replacement.

In the present invention, the foaming agent is preferably inorganic fiber, azodicarbonamide, alum or organic polymer.

The denitrifying carbon source layer in the present invention is prepared from the following raw materials by weight: 40-50 parts of kitchen waste oil, 4-6 parts of sodium hydroxide, 16-20 parts of water, 6 parts of 95% ethanol, 2-4 parts of polylactic acid powder, 0.05-0.1 part of curing agent, 0.5-1 part of structural stabilizer and 0.5-2 parts of reinforcing agent. In the present invention, the prepared kitchen waste oil preferably contains higher fatty acid glycerides and fatty acid polymers, and the mass content of the higher fatty acid glycerides is preferably more than 80%.

In the present invention, the emulsifier is preferably propylene glycol fatty acid ester or lauric acid monoglyceride.

In the present invention, the curing agent is preferably methyl ethyl ketone peroxide, the structure stabilizer is preferably disodium EDTA, and the reinforcing agent is preferably polypropylene staple fibers. In the present invention, the polylactic acid powder can enhance the carbon release effect of the denitrifying carbon source, and the reinforcing agent polypropylene short fiber can improve the mechanical strength of the denitrifying carbon source.

The present invention does not specifically limit the sources of the raw materials, and commercial products well known to those skilled in the art can be used.

The present invention also provides the preparation method of the denitrifying carbon source described in the above technical solution, comprising the following steps:

The waste kitchen oil is heated, cooled and filtered in turn to obtain pretreated waste oil;

Carry out adsorption reaction with the pretreated waste oil and activated clay to obtain refined waste oil;

Carry out saponification reaction with sodium hydroxide and water after preheating the refining waste oil to obtain a saponification product;

The saponification product, ethanol, polylactic acid powder, curing agent, structural stabilizer and reinforcing agent are mixed and then granulated to obtain denitrifying carbon source particles of kitchen waste oil;

Mix sodium alginate, emulsifier and water to obtain emulsion;

Mixing the emulsion, water-based polyurethane and foaming agent to obtain a film-coated emulsion;

The denitrifying carbon source particles of the kitchen waste oil are coated with the coating emulsion to obtain the denitrifying carbon source.

In the invention, the waste kitchen oil is heated, cooled and filtered in turn to obtain the pretreated waste oil. In the present invention, the heating is preferably heating the kitchen waste oil to boiling. In the present invention, heating can remove moisture. The present invention does not have a special limitation on the heating rate, and a heating method well known to those skilled in the art can be used.

In the present invention, the final temperature of the cooling is preferably 40 to 50°C.

The present invention does not have a special limitation on the filtering method, and a filtering method well known to those skilled in the art can be adopted. The present invention removes sand particles, plastic dust and some organic matter carbides in the kitchen waste oil by filtering.

After the pretreated waste oil is obtained, the present invention performs adsorption reaction on the pretreated waste oil and activated clay to obtain refined waste oil. In the present invention, the mass ratio of the pretreated waste oil and the activated clay is preferably 1-2:20, more preferably 1:20.

In the present invention, the temperature of the adsorption reaction is preferably 100-120° C., and the time is preferably 30-60 min. In the present invention, the adsorption reaction can remove unfiltered impurities and decolorize.

After the adsorption reaction is completed, the present invention preferably cools the adsorption product to 40-50° C., and then performs suction filtration with a vacuum suction filtration device to obtain refined waste oil.

After the refining waste oil is obtained, in the present invention, the refining waste oil is preheated and subjected to a saponification reaction with sodium hydroxide and water to obtain a saponified product. In the present invention, the saponification product is a viscous opaque liquid. In the present invention, the temperature of the preheating is preferably 85 to 90°C.

In the present invention, the temperature of the saponification reaction is preferably 85-90° C., and the time is preferably 30-60 min.

In the present invention, the mass ratio of the refining waste oil to sodium hydroxide is preferably 8-12:1, more preferably 10:1-25:3.

In the present invention, the sodium hydroxide and water are preferably mixed to obtain a sodium hydroxide solution and then added to the preheated refining waste oil. In the present invention, the mass concentration of the sodium hydroxide solution is preferably 20% to 40%.

After obtaining the saponified product, the present invention mixes the saponified product, ethanol, polylactic acid powder, curing agent, structural stabilizer and reinforcing agent and granulates to obtain denitrifying carbon source particles of kitchen waste oil. The present invention does not specifically limit the specific method of the mixing and granulation, and a method well known to those skilled in the art can be adopted, specifically, such as granulation in a cold-cut granulator.

After mixing, the present invention preferably pours the mixture into a glass container and cools it to normal temperature, and then puts it into an oven for drying. The present invention has no particular limitation on the specific manner of the cooling and drying, and a manner well known to those skilled in the art may be adopted.

In the present invention, sodium alginate, emulsifier and water are mixed to obtain emulsion.

After the emulsion is obtained, the present invention mixes the emulsion, the aqueous polyurethane and the foaming agent to obtain a film-coated emulsion. The preparation method of the coating emulsion in the present invention can improve the strength and stability of the coating layer.

After obtaining the coated emulsion and the denitrifying carbon source particles of the waste kitchen oil, the present invention uses the coated emulsion to coat the particles of the denitrifying carbon source of the waste kitchen oil to obtain the denitrifying carbon source. In the present invention, the coating is preferably carried out in a coating machine.

After the coating is completed, in the present invention, the coated product is preferably dried to obtain a denitrifying carbon source. The present invention does not specifically limit the specific operation of the drying, and a method well known to those skilled in the art can be used.

The denitrifying carbon source provided by the present invention and its preparation method are described in detail below in conjunction with the examples, but they should not be construed as limiting the protection scope of the present invention.

Comparative Example 1

The denitrification biological filter uses ceramsite as the filler and the water flow is upward flow. The inoculation method is used to start the film, and then the wastewater (C/N is 3:1) is introduced into the denitrification biological filter. The operating conditions The temperature is 25℃, the pH value is 7.5, the hydraulic retention time is 3h, and the DO is 0.2mg/L. After stable operation, the nitrogen removal rate is 46%, the effluent pH is 6.9, and the effluent COD is 25mg/L.

Comparative Example 2

The denitrification biological filter uses ceramsite as the filler and the water flow is upward flow. The inoculation method is used to start the film, and then the wastewater (C/N is 3:1) is introduced into the denitrification biological filter. The operating conditions The temperature is 30℃, the pH value is 7.3, the hydraulic retention time is 5h, and the DO is 0.3mg/L. After stable operation, the nitrogen removal rate is 41%, the effluent pH is 7.0, and the effluent COD is 20mg/L.

Comparative Example 3

The denitrification biological filter uses ceramsite as filler and the water flow is upward flow. The inoculation method is used to start the film, and then the waste water is added with ethanol as a supplementary carbon source (C/N is 10:1) into the reaction tank. Nitrification biological filter, the operating conditions are temperature 30℃, pH value 7.3, hydraulic retention time 5h, DO 0.3mg/L, after stable operation, nitrogen removal rate is 92%, effluent pH is 6.8, effluent COD is 100mg /L

Example 1

A denitrifying carbon source is mainly composed of an inner and outer two-layer structure, the outer layer is a coating layer, and the inner layer is a denitrifying carbon source layer made of kitchen waste oil, wherein the outer layer of the denitrifying carbon source is composed of the following parts by weight : Contains 30 parts of water-based polyurethane, 6 parts of sodium alginate, 2 parts of foaming agent, and 4 parts of emulsifier. The inner layer is mainly prepared by the following parts by weight: including 40 parts of kitchen waste oil, 4 parts of sodium hydroxide solid, 16 parts of distilled water, 6 parts of 95% alcohol solution, 2 parts of polylactic acid powder, 0.05 part of curing agent, structural stabilizer 0.5 part, 0.5 part of reinforcement.

The foaming agent is inorganic fiber, the emulsifier is propylene glycol fatty acid ester, the curing agent is methyl ethyl ketone peroxide, the structure stabilizer is disodium EDTA, and the reinforcing agent is polypropylene staple fiber.

A preparation method of denitrifying carbon source, comprising the following steps

(1) Waste oil refining

Step 1: Heat the waste oil to boiling to remove excess water. After the oil temperature drops to 40°C, filter to remove impurities in the oil.

Step 2: Add activated clay in proportion to the waste oil treated in step 1 (the mass ratio of waste oil and activated clay is 20:1), fully react and heat to 120°C, stir for 30min, and when the temperature drops to 40°C, The oil is filtered out by a vacuum filtration device to obtain refined waste oil.

(2) Preparation of denitrifying carbon source layer

Step 1: Pour the refined waste oil into a stainless steel pot and heat it to 90°C.

Step 2: Dissolve sodium hydroxide into distilled water, the mass ratio of sodium hydroxide and kitchen waste oil is 1:10, form a 40% sodium hydroxide solution, slowly add it to the refining waste oil at 90 ° C and stir for about 30min .

Step 3: After the liquid is viscous and opaque, add 50% alcohol solution (the volume ratio of 95% alcohol solution to distilled water is 3:1), polylactic acid powder, curing agent, structural stabilizer, and reinforcing agent. After stirring evenly, Let stand for 1 hour, drain excess water, pour it into a glass container, cool to 25°C, and then put it into a 60°C oven to dry for 24 hours.

Step 4: take the dried solid and send it to a cold granulator for granulation to obtain denitrifying carbon source particles of kitchen waste oil.

(3) Preparation of the coating layer

Add sodium alginate and emulsifier into distilled water, and stir to form an emulsion. At this time, add the above-mentioned aqueous polyurethane and foaming agent, and continue to stir until a colloidal emulsion is formed.

(4) Coating of denitrifying carbon source particles

Add the coating emulsion into the coating machine to coat the denitrifying carbon source particles. After the coating is completed, put it into a 45°C oven to dry for 12 hours to obtain the finished kitchen waste oil denitrifying carbon source.

The density of the prepared denitrifying carbon source was 1.13 g/cm ³ .

The denitrifying carbon source prepared above is loaded into the bottom of the denitrifying biological filter, the filling ratio is 10%, the upper layer is ceramsite filler, the water flow is upward flow, and the inoculation hanging film method is used to start the film hanging, and then waste water. (C/N is 3:1) Introduced into the denitrification biological filter, the operating conditions are the temperature of 25 ° C, the pH value of 7.5, the hydraulic retention time of 3 hours, and the DO of 0.2 mg/L. After stable operation, the biological denitrification meets zero. First-order reaction kinetics, the rate was 1.96 gN/m ³ ·d, the removal rate was 86%, and the effluent COD was 40 mg/L.

Example 2

A denitrifying carbon source is mainly composed of an inner and outer two-layer structure, the outer layer is a coating layer, and the inner layer is a denitrifying carbon source layer made of kitchen waste oil, wherein the outer layer of the denitrifying carbon source is mainly composed of the following parts by weight Composition: including 30 parts of water-based polyurethane, 6 parts of sodium alginate, 2 parts of foaming agent, and 4 parts of emulsifier. The inner layer is mainly prepared by the following parts by weight: including 50 parts of kitchen waste oil, 6 parts of sodium hydroxide solid, 20 parts of distilled water, 6 parts of 95% alcohol solution, 4 parts of polylactic acid powder, 0.05 part of curing agent, structural stabilizer 1 part, 1 part of reinforcement.

The foaming agent is azodicarbonamide, the emulsifier is lauric acid monoglyceride, the curing agent is methyl ethyl ketone peroxide, the stabilizer is disodium EDTA, and the reinforcing agent is polypropylene staple fiber.

The preparation method of the denitrifying carbon source comprises the following steps

(1) Refining of waste oil (same as Example 1)

(2) Preparation of denitrifying carbon source layer

Step 1: Pour the kitchen waste oil into a stainless steel pot and heat it to 90°C.

Step 2: Dissolve sodium hydroxide into distilled water, the mass ratio of sodium hydroxide to kitchen waste oil is 3:25, to form a 50% sodium hydroxide solution, slowly add it to the kitchen waste oil at 90 ° C and stir for about 30min.

Step 3: After the liquid is viscous and opaque, add 40% alcohol solution (the volume ratio of 95% alcohol solution and distilled water is 6:8), polylactic acid powder, curing agent, structural stabilizer, and reinforcing agent. After stirring evenly, Let stand for 1 hour, drain excess water, pour it into a glass container, cool to 25°C, and then put it into a 60°C oven to dry for 24 hours.

Step 4: take the dried solid and send it to a cold granulator for granulation to obtain denitrifying carbon source particles of kitchen waste oil.

(3) Preparation of the coating layer

Add sodium alginate and emulsifier into distilled water, and stir to form an emulsion. At this time, add the above-mentioned aqueous polyurethane and foaming agent, and continue to stir until a colloidal emulsion is formed.

(4) Coating of denitrifying carbon source particles

Add the coating emulsion into the coating machine to coat the denitrifying carbon source particles. After the coating is completed, put it into a 45°C oven to dry for 12 hours to obtain the finished kitchen waste oil denitrifying carbon source.

The density of the prepared denitrifying carbon source was 1.21 g/cm ³ .

Place the prepared denitrifying carbon source in a bucket filled with 25L of clean water with a pH of 7 for 12 hours, and measure the pH of the clean water with a pH meter at the time points of 4h, 8h, and 12h, which are 7.3, 7.4, and 7.6 respectively. , it can be judged that the prepared denitrifying carbon source is alkaline and can be released slowly.

The denitrifying carbon source prepared above is loaded into the bottom of the denitrifying biological filter, the filling ratio is 15%, the upper layer is ceramsite filler, the water flow is upward flow, and the film hanging method is used to start the film, and then the wastewater is (C/N is 3:1) The denitrification biological filter was introduced. The operating conditions were the temperature of 30 °C, the pH value of 7.3, the hydraulic retention time of 5 h, and the DO of 0.3 mg/L. After stable operation, the biological denitrification met zero. The kinetics of the first-order reaction was 2.13 gN/m ³ ·d, the removal rate was 92%, the pH of the effluent was 7.4, and the COD of the effluent was 45 mg/L.

Comparing Comparative Example 1 with Example 1, it can be seen that the denitrification efficiency of Example 1 is significantly higher, the pH of the effluent is stable, and the quality of the effluent is good.

Comparing Comparative Example 2 with Example 2, it can be seen that the denitrification effect of Example 2 is significantly higher, the pH of the effluent is closer to the initial value, and the quality of the effluent is better.

Comparing Comparative Example 3 with Example 2, it can be seen that the decarburization effect of the two is the same, but the effluent COD of Example 2 is low, the pH is stable, and the effluent quality is better.

A sewage treatment plant in Bengbu, Anhui, adopts A ² /O process. The last process of biological treatment is denitrification biological filter. Methanol is added as a supplementary carbon source for denitrification. The indicators of the influent and effluent of the denitrification tank are shown in Table 1. shown.

Table 1 Various indicators of influent and effluent after denitrification of methanol

After the denitrifying carbon source prepared by the method of Example 2 was added to the denitrification filter to run stably for 30 days instead of methanol, the indicators of the influent and effluent of the denitrification tank are shown in Table 2.

The indicators of the influent and effluent after the denitrifying carbon source prepared by the method of table 2 embodiment 2 carries out denitrification

Comparing Table 1 and Table 2, it can be seen that the pH of the effluent of the denitrification filter using the denitrifying carbon source of kitchen waste oil is closer to the optimum pH of the denitrifying bacteria (7.5), and the COD of the effluent is lower, and the price is only the price of methanol. About 60%, the denitrification efficiency is close. Greatly reduces the cost of dosing.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (9)

1. The denitrification carbon source is characterized by comprising an inner layer and an outer layer, wherein the outer layer is a coating layer, the inner layer is a denitrification carbon source layer, and the coating layer comprises the following components in parts by weight: 20-30 parts of water-based polyurethane, 4-6 parts of sodium alginate, 1-2 parts of foaming agent and 3-5 parts of emulsifier; the denitrification carbon source layer is prepared from the following raw materials in parts by weight: 40-50 parts of kitchen waste oil, 4-6 parts of sodium hydroxide, 16-20 parts of water, 6 parts of 95% ethanol, 2-4 parts of polylactic acid powder, 0.05-0.1 part of curing agent, 0.5-1 part of structure stabilizer and 0.5-2 parts of reinforcing agent; the curing agent is methyl ethyl ketone peroxide, the structure stabilizer is disodium ethylene diamine tetraacetate, and the reinforcing agent is polypropylene short fiber;

the preparation method of the denitrification carbon source comprises the following specific steps:

sequentially heating, cooling and filtering the kitchen waste oil to obtain pretreated waste oil;

carrying out adsorption reaction on the pretreated waste oil and activated clay to obtain refined waste oil;

preheating the refined waste oil, and then performing saponification reaction on the refined waste oil, sodium hydroxide and water to obtain a saponified product;

mixing the saponification product, ethanol, polylactic acid powder, a curing agent, a structure stabilizer and a reinforcing agent, and then granulating to obtain kitchen waste oil denitrification carbon source particles;

mixing sodium alginate, an emulsifier and water to obtain an emulsion;

mixing the emulsion, water-based polyurethane and a foaming agent to obtain a coating emulsion;

and coating the kitchen waste oil denitrification carbon source particles by adopting the coating emulsion to obtain a denitrification carbon source.

2. The denitrification carbon source of claim 1, wherein the mass ratio of the inner layer to the outer layer is 10: 2-3.

3. The denitrifying carbon source of claim 1, wherein the foaming agent is inorganic fiber, azodicarbonamide, alum, or an organic polymer.

4. The denitrifying carbon source according to claim 1, wherein the emulsifier is propylene glycol fatty acid ester or lauric acid monoglyceride.

5. The method for preparing the denitrification carbon source of any one of claims 1 to 4, which is characterized by comprising the following steps:

sequentially heating, cooling and filtering the kitchen waste oil to obtain pretreated waste oil;

carrying out adsorption reaction on the pretreated waste oil and activated clay to obtain refined waste oil;

preheating the refined waste oil, and then performing saponification reaction on the refined waste oil, sodium hydroxide and water to obtain a saponified product;

mixing the saponification product, ethanol, polylactic acid powder, a curing agent, a structure stabilizer and a reinforcing agent, and then granulating to obtain kitchen waste oil denitrification carbon source particles;

mixing sodium alginate, an emulsifier and water to obtain an emulsion;

mixing the emulsion, water-based polyurethane and a foaming agent to obtain a coating emulsion;

and coating the kitchen waste oil denitrification carbon source particles by adopting the coating emulsion to obtain a denitrification carbon source.

6. The preparation method according to claim 5, wherein the mass ratio of the pretreated waste oil to the activated clay is 1-2: 20.

7. The method according to claim 5, wherein the temperature of the adsorption reaction is 100 to 120 ℃ and the time is 30 to 60 min.

8. The method according to claim 5, wherein the saponification is carried out at 85 to 90 ℃ for 30 to 60 min.

9. The preparation method according to claim 5, wherein the mass ratio of the refined waste oil to the sodium hydroxide is 8-12: 1.