Carbon source agent for sewage treatment and preparation method and application thereof

Abstract

The present invention discloses a carbon source agent for sewage treatment, and a preparation method and application thereof. The carbon source agent for sewage treatment of the present invention, its preparation raw materials include a carbon source solid matrix and a wrapping material, wherein: the carbon source solid matrix includes a cellulose carbon source, a biodegradable polymer carbon source, a binder and a low molecular weight carbon source; the weight ratio of the cellulose carbon source, the biodegradable polymer carbon source and the low molecular weight carbon source is 1.5 to 2.5:1 to 1.5:1; the wrapping material includes at least one of attapulgite or bentonite. The carbon source agent for sewage treatment of the present invention has a good sustained release effect. Using the carbon source agent for sewage treatment of the present invention for sewage treatment can effectively improve the denitrification efficiency, and has a wide range of application value in the field of sewage treatment.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, in particular to a sewage treatment carbon source agent and a preparation method and application thereof. Background Art

[0002] The carbon source for sewage treatment is a carbon-containing compound that can provide nutrients for the growth and metabolism of microorganisms in the sewage biochemical treatment system. At present, there are many studies at home and abroad on the enhancement of wastewater denitrification performance by adding external carbon sources. Commonly used external carbon sources in the process of wastewater denitrification include sodium acetate, methanol, ethanol, acetic acid and fructose, which have better denitrification effects in the sewage treatment process. However, in actual application, the long-term use of a single carbon source will lead to a single microbial denitrification pathway and a reduction in enzyme types in the sewage treatment system, which will lead to poor total nitrogen removal.

[0003] Composite carbon sources are carbon sources composed of two or more effective carbon source components, which can effectively avoid the overgrowth of some microorganisms caused by a single carbon source. When composite carbon sources are used as electron donors for denitrification reactions, they help increase the abundance of efficient denitrifying bacteria, change the colony structure, and thus improve the denitrification effect. However, in practical applications, composite carbon sources still have unsatisfactory denitrification effects.

[0004] Therefore, there is still a need to seek a carbon source agent for sewage treatment and a preparation method and application thereof. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a carbon source agent for sewage treatment and a preparation method and application thereof. The carbon source agent for sewage treatment of the present invention has an excellent effect on improving the denitrification effect.

[0006] The invention also provides a method for preparing a carbon source agent for sewage treatment.

[0007] The invention also proposes the application of a sewage treatment carbon source agent in sewage treatment.

[0008] In a first aspect of the present invention, a carbon source agent for sewage treatment is provided, wherein the raw materials for preparing the carbon source agent include a carbon source solid matrix and a packaging material, wherein:

[0009] The carbon source solid matrix includes a cellulose carbon source, a biodegradable polymer carbon source, a binder and a low molecular weight carbon source;

[0010] The weight ratio of the cellulose carbon source, the biodegradable polymer carbon source and the low molecular weight carbon source is 1.5-2.5:1-1.5:1;

[0011] The packaging material includes at least one of attapulgite or bentonite.

[0012] The carbon source agent for sewage treatment according to the embodiment of the present invention has at least the following beneficial effects:

[0013] (1) The present invention can effectively avoid the excessive reproduction of some microorganisms caused by a single carbon source by rationally combining low molecular weight carbon sources, cellulose carbon sources and biodegradable polymer carbon sources, thereby improving the denitrification and denitrification effect of the carbon source agent. Secondly, the present invention effectively improves the stability and durability of carbon release by rationally combining carbon sources with different molecular weights.

[0014] (2) The present invention wraps a layer of attapulgite or bentonite on the surface of the prepared carbon source solid matrix. Attapulgite is a crystalline hydrated magnesium aluminum silicate mineral that is sticky and plastic when wet, shrinks little after drying, does not crack, has good water absorption and excellent adsorption, and can assist in sewage decolorization and deammoniation. Wrapping it on the surface of the carbon source solid matrix not only helps to improve the sewage treatment effect and prevent secondary pollution (some cellulose carbon sources may produce odor or increase in color during the decomposition process by microorganisms. Using attapulgite or bentonite as a wrapping material can adsorb it and prevent secondary pollution), but also can improve the stability of the carbon source solid matrix and prevent the COD content from being too high due to the solid carbon source releasing carbon too quickly.

[0015] (3) The sewage treatment carbon source agent of the present invention is a carbon source composed of multiple effective carbon source components, which can effectively avoid the excessive reproduction of some microorganisms caused by a single carbon source. When the sewage treatment carbon source agent of the present invention is used as an electron donor for the denitrification reaction, it helps to increase the abundance of high-efficiency denitrifying bacteria, thereby improving the denitrification effect.

[0016] In some embodiments of the present invention, the sewage treatment carbon source agent includes, by weight: 15 to 25 parts of cellulose carbon source, 12 to 18 parts of biodegradable polymer carbon source, 12 to 20 parts of binder, 8 to 15 parts of low molecular weight carbon source, 15 to 20 parts of packaging material and 20 to 40 parts of water.

[0017] In some embodiments of the present invention, the cellulosic carbon source includes at least one of corn cobs, rice straws, reed straws, and chestnut shells.

[0018] In some embodiments of the present invention, the cellulose carbon source includes corn cobs, and at least one of rice straw, reed straw, and chestnut shells.

[0019] Preferably, the cellulosic carbon source is corn cob, rice straw or reed straw.

[0020] In some embodiments of the present invention, the biodegradable polymer carbon source includes at least one of polycaprolactone, poly-β-hydroxybutyric acid, and polylactic acid.

[0021] Biodegradable polymer carbon sources are high molecular weight materials that can undergo chemical, biological or physical degradation or enzymatic hydrolysis under the action of microorganisms existing in nature, such as bacteria, fungi, and algae. The polymers (amide groups, ester groups, etc.) existing on their molecular chains are easily decomposed and have good mechanical strength and nitrogen removal effects.

[0022] In some embodiments of the present invention, the binder is starch.

[0023] In some embodiments of the present invention, the low molecular weight carbon source is at least one of sodium acetate, citric acid, and fructose.

[0024] The carbon release effect and denitrification utilization rate of small molecular weight carbon sources are generally higher than those of cellulose carbon sources, but the carbon release is not persistent enough and it is easy to cause high COD content in water, causing secondary pollution; the carbon release persistence of cellulose carbon sources is better, but the carbon release amount is low in the early stage of release. The present invention effectively makes up for the shortcomings of both through reasonable combination.

[0025] In addition, the present invention adds a variety of carbon sources, which is beneficial to promoting the growth of a variety of denitrifying bacteria, increasing the diversity of denitrifying bacteria, and thus improving the denitrification and denitrification effect.

[0026] In some embodiments of the present invention, the sewage treatment carbon source agent further comprises 1 to 3 parts of sulfate in parts by weight;

[0027] Preferably, the sulfate includes at least one of sodium sulfate and potassium sulfate.

[0028] Adding an appropriate amount of sulfate to the carbon source is beneficial to promoting the growth and metabolism of microorganisms and improving the sewage treatment effect.

[0029] In some embodiments of the present invention, the sewage treatment carbon source agent includes, by weight: 15 to 25 parts of cellulose carbon source, 12 to 18 parts of biodegradable polymer carbon source, 12 to 20 parts of binder, 8 to 15 parts of low molecular weight carbon source, 15 to 20 parts of packaging material, 1 to 3 parts of sulfate and 20 to 40 parts of water.

[0030] The second aspect of the present invention provides a method for preparing a carbon source agent for sewage treatment, comprising the following preparation steps:

[0031] Step S1, mixing the binder and part of the water for gelatinization, then adding the cellulose carbon source, the biodegradable polymer carbon source, the low molecular weight carbon source and the sulfate, stirring evenly, and granulating to obtain a carbon source solid matrix;

[0032] Step S2: Mix the wrapping material with the remaining water, stir until viscous, and wrap it on the surface of the carbon source solid matrix, and dry it to obtain the product.

[0033] The preparation method according to the embodiment of the present invention has at least the following beneficial effects: the temperature of the gelatinization treatment is 60-70°C.

[0034] In some embodiments of the present invention, the drying temperature is 50-60°C;

[0035] Preferably, the drying time is 12 to 18 hours.

[0036] The third aspect of the present invention provides an application of a sewage treatment carbon source agent in sewage treatment.

[0037] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. DETAILED DESCRIPTION

[0038] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0039] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0040] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0041] In the embodiments of the present invention, attapulgite was purchased from Jiangsu Huixin Attapulgite Co., Ltd.; bentonite was purchased from Lingshou County Jieling Mineral Products Trading Co., Ltd., a strong supplier.

[0042] The carbon source agents for sewage treatment of Examples 1 to 6 of the present invention are shown in Table 1.

[0043] Table 1: Carbon source reagent components for sewage treatment of Examples 1 to 6 (in parts by weight)

[0044]

[0045] Example 1

[0046] The present embodiment provides a carbon source agent for sewage treatment, which includes a cellulose carbon source, a biodegradable polymer carbon source, a binder, a low molecular weight carbon source, a sulfate, a packaging material and water, wherein the cellulose carbon source is corn cobs and rice husks, the biodegradable polymer carbon source is polycaprolactone, the low molecular weight carbon source is sodium acetate and citric acid, the binder is starch, the sulfate is sodium sulfate, and the packaging material is attapulgite.

[0047] In terms of weight percentage, the weight percentage of each component is as shown in Example 1 in Table 1.

[0048] The preparation method of the carbon source agent for sewage treatment in this embodiment comprises the following steps:

[0049] Step S1, mixing starch with part of water, heating the starch at 65° C. until gelatinization, then sequentially adding polycaprolactone, sodium acetate, citric acid, sodium sulfate, crushed corn cob and rice straw powder that have passed through a 60-mesh sieve, mixing evenly and granulating to obtain a carbon source solid matrix;

[0050] Step S2, mixing attapulgite with another part of water until it becomes viscous, and then wrapping it on the surface of the carbon source solid matrix prepared above, and drying it at 55° C. to obtain a carbon source agent for sewage treatment with a diameter of 2 to 4 cm.

[0051] Example 2

[0052] The present embodiment provides a carbon source agent for sewage treatment, which includes a cellulose carbon source, a biodegradable polymer carbon source, a binder, a low molecular weight carbon source, a sulfate, a wrapping material and water, wherein the cellulose carbon source is corn cobs and reed stalks, the biodegradable polymer carbon source is polycaprolactone, the low molecular weight carbon source is sodium acetate and citric acid, the binder is starch, the sulfate is sodium sulfate, and the wrapping material is attapulgite.

[0053] In terms of weight percentage, the weight percentage of each component is specifically shown in Example 2 in Table 1.

[0054] The preparation method of the carbon source agent for sewage treatment in this embodiment comprises the following steps:

[0055] Step S1, mixing starch with part of water, heating the starch at 65° C. until gelatinization, then sequentially adding polycaprolactone, sodium acetate, citric acid, sodium sulfate, crushed corn cob and reed stalk powder that have passed through a 60-mesh sieve, mixing evenly and granulating to obtain a carbon source solid matrix;

[0056] Step S2, mixing attapulgite with another part of water until it becomes viscous, and then wrapping it on the surface of the carbon source solid matrix prepared above, and drying it at 55° C. to obtain a carbon source agent for sewage treatment with a diameter of 2 to 4 cm.

[0057] Example 3

[0058] The present embodiment provides a carbon source agent for sewage treatment, which includes a cellulose carbon source, a biodegradable polymer carbon source, a binder, a low molecular weight carbon source, a sulfate, a packaging material and water, wherein the cellulose carbon source is corn cobs and chestnut shells, the biodegradable polymer carbon source is polycaprolactone, the low molecular weight carbon source is sodium acetate and citric acid, the binder is starch, the sulfate is sodium sulfate, and the packaging material is attapulgite.

[0059] In terms of weight percentage, the weight percentage of each component is specifically shown in Example 3 in Table 1.

[0060] The preparation method of the carbon source agent for sewage treatment in this embodiment comprises the following steps:

[0061] Step S1, mixing starch with part of water, heating the starch at 65° C. until gelatinization, then sequentially adding polycaprolactone, sodium acetate, citric acid, sodium sulfate, crushed corn cob and chestnut shell powder that have been sieved through a 60-mesh sieve, mixing evenly and granulating to obtain a carbon source solid matrix;

[0062] Step S2, mixing attapulgite with another part of water until it becomes viscous, and then wrapping it on the surface of the carbon source solid matrix prepared above, and drying it at 55° C. to obtain a carbon source agent for sewage treatment with a diameter of 2 to 4 cm.

[0063] Example 4

[0064] The present embodiment provides a carbon source agent for sewage treatment, which includes a cellulose carbon source, a biodegradable polymer carbon source, a binder, a low molecular weight carbon source, a sulfate, a packaging material and water, wherein the cellulose carbon source is corn cobs and rice husks, the biodegradable polymer carbon source is polycaprolactone, the low molecular weight carbon source is sodium acetate and citric acid, the binder is starch, the sulfate is sodium sulfate, and the packaging material is attapulgite.

[0065] In terms of weight percentage, the weight percentage of each component is specifically shown in Example 4 in Table 1.

[0066] The preparation method of the carbon source agent for sewage treatment in this embodiment comprises the following steps:

[0067] Step S1, mixing starch with part of water, heating the starch at 65° C. until gelatinization, then sequentially adding polycaprolactone, sodium acetate, citric acid, sodium sulfate, crushed corn cob and rice straw powder that have passed through a 60-mesh sieve, mixing evenly and granulating to obtain a carbon source solid matrix;

[0068] Step S2, mixing attapulgite with another part of water until it becomes viscous, and then wrapping it on the surface of the carbon source solid matrix prepared above, and drying it at 55° C. to obtain a carbon source agent for sewage treatment with a diameter of 2 to 4 cm.

[0069] Example 5

[0070] The present embodiment provides a carbon source agent for sewage treatment, which includes a cellulose carbon source, a biodegradable polymer carbon source, a binder, a low molecular weight carbon source, a sulfate, a packaging material and water, wherein the cellulose carbon source is corn cobs and rice husks, the biodegradable polymer carbon source is polycaprolactone, the low molecular weight carbon source is sodium acetate and citric acid, the binder is starch, the sulfate is sodium sulfate, and the packaging material is attapulgite.

[0071] In terms of weight percentage, the weight percentage of each component is as shown in Example 5 in Table 1.

[0072] The preparation method of the carbon source agent for sewage treatment in this embodiment comprises the following steps:

[0073] Step S1, mixing starch with part of water, heating the starch at 65° C. until gelatinization, then sequentially adding polycaprolactone, sodium acetate, citric acid, sodium sulfate, crushed corn cob and rice straw powder that have passed through a 60-mesh sieve, mixing evenly and granulating to obtain a carbon source solid matrix;

[0074] Step S2, mixing attapulgite with another part of water until it becomes viscous, and then wrapping it on the surface of the carbon source solid matrix prepared above, and drying it at 55° C. to obtain a carbon source agent for sewage treatment with a diameter of 2 to 4 cm.

[0075] Example 6

[0076] The present embodiment provides a carbon source agent for sewage treatment, which includes a cellulose carbon source, a biodegradable polymer carbon source, a binder, a low molecular weight carbon source, a sulfate, a packaging material and water, wherein the cellulose carbon source is corn cobs and rice husks, the biodegradable polymer carbon source is polycaprolactone, the low molecular weight carbon source is citric acid and fructose, the binder is starch, the sulfate is sodium sulfate, and the packaging material is bentonite.

[0077] In terms of weight percentage, the weight percentage of each component is specifically shown in Example 6 in Table 1.

[0078] The preparation method of the carbon source agent for sewage treatment in this embodiment comprises the following steps:

[0079] Step S1, mixing starch with part of water, heating the starch at 65° C. until gelatinization, then sequentially adding polycaprolactone, fructose, citric acid, sodium sulfate, crushed corn cob and rice straw powder that have passed through a 60-mesh sieve, mixing evenly and granulating to obtain a carbon source solid matrix;

[0080] Step S2, mixing bentonite with another portion of water until they are viscous, and then wrapping the bentonite on the surface of the carbon source solid matrix prepared above, and drying at 55° C. to obtain a carbon source agent for sewage treatment with a diameter of 2 to 4 cm.

[0081] Comparative Example 1

[0082] The difference between this comparative example and Example 1 is that no cellulose carbon source is added.

[0083] Comparative Example 2

[0084] The difference between this comparative example and Example 1 is that no biodegradable polymer carbon source is added.

[0085] Comparative Example 3

[0086] The difference between this comparative example and Example 1 is that no low molecular weight carbon source is added.

[0087] Comparative Example 4

[0088] The difference between this comparative example and Example 1 is that no sulfate is added.

[0089] Comparative Example 5

[0090] The difference between this comparative example and Example 1 is that the surface of the prepared carbon source solid matrix is ​​not coated with attapulgite.

[0091] Comparative Example 6

[0092] The difference between this comparative example and Example 1 is that, based on weight parts, the corn cobs are 16 parts, the rice straws are 16 parts, the polycaprolactone is 8 parts, the sodium acetate is 2.5 parts, and the citric acid is 2.5 parts.

[0093] Application Examples

[0094] The carbon source agents for sewage treatment prepared in Examples 1 to 6 of the present invention and Comparative Examples 1 to 6 are respectively used for sewage treatment, and the specific method is as follows:

[0095] First, the sewage to be treated enters a sedimentation tank, where colloids and fine suspended matter therein are condensed to form flocs under the action of a coagulant, and then enters an aerated biological filter for carbonization and nitrification after the flocs are separated and removed; the effluent from the aerated biological filter enters a denitrification filter, in which the carbon source agent for sewage treatment of the present invention is added to assist in denitrification, wherein 1 g of the carbon source agent for sewage treatment is added per liter of sewage to remove total nitrogen in the water; the effluent from the denitrification filter enters a sand filter and a catalytic oxidation tank in sequence to finally obtain purified water, and the pH value, chemical oxygen demand COD and total nitrogen content of the purified water are detected on the 10th day after the addition.

[0096] Among them, in this application example, the pH value is detected according to the electrode method specified in the HJ 1147-2020 standard; the chemical oxygen demand COD is determined according to the dichromate method specified in the HJ / T 828-2017 standard; the total nitrogen content is determined according to the alkaline potassium persulfate digestion ultraviolet spectrophotometry specified in the HJ 636-2012 standard.

[0097] The test results are shown in Table 2.

[0098] Table 2: Test results

[0099] COD(mg / L) TN(mg / L) pH Initial water quality 197.74 51.41 6.8 Example 1 11.23 7.74 7.2 Example 2 11.62 7.97 7 Example 3 12.77 8.55 7.1 Example 4 14.51 8.86 7.2 Example 5 13.65 7.63 7.2 Example 6 12.56 7.62 7.3 Comparative Example 1 18.68 19.41 6.8 Comparative Example 2 15.54 18.62 6.9 Comparative Example 3 13.23 16.74 6.8 Comparative Example 4 14.66 17.22 6.9 Comparative Example 5 16.85 20.44 6.7 Comparative Example 6 13.54 14.32 6.9

[0100] It can be analyzed from the above test results that the carbon source agent for sewage treatment of the present invention has an excellent denitrification effect, and can reduce the total nitrogen content of the initial sewage at the inlet from 51.41 mg / L to below 10 mg / L, and the total nitrogen removal rate reaches more than 80%, and the COD value level reaches the first-class water quality standard (≤15 mg / L), which further illustrates that the carbon source agent for sewage treatment of the present invention helps to improve the growth metabolism of denitrifying bacteria in the denitrification filter, thereby improving the denitrification efficiency.

[0101] The difference between Comparative Examples 1 to 5 and Example 1 is that at least one of the cellulose carbon source, biodegradable polymer carbon source, low molecular weight carbon source, sulfate and attapulgite is not added. From the test results, it can be seen that it has a certain impact on the COD value of the effluent or the final total nitrogen content. Among them, no cellulose carbon source was added in Comparative Example 1 (resulting in an increase in the relative content of the corresponding biodegradable polymer carbon source and the low molecular weight carbon source in the actual treatment process), and from the test results, it can be seen that the corresponding COD content exceeds the standard (greater than 15 mg / L), which is not conducive to the growth of denitrifying bacteria in the denitrification filter, and is prone to secondary pollution.

[0102] The difference between Comparative Example 6 and Example 1 is that the relative content of cellulose carbon source is higher. From the test results, it can be seen that high cellulose carbon source is not conducive to improving denitrification efficiency.

[0103] In summary, the present invention provides a carbon source agent for sewage treatment and a preparation method and application thereof. The carbon source agent for sewage treatment of the present invention helps to increase the abundance of high-efficiency denitrifying bacteria, change the colony structure, and thus improve the denitrification effect. It can be widely used in rural or urban sewage treatment and has good application prospects.

[0104] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A carbon source agent for sewage treatment, It is characterized in that The preparation raw materials include a carbon source solid matrix and a wrapping material, wherein: the carbon source solid matrix includes a cellulose carbon source, a biodegradable polymer carbon source, a binder and a small molecular weight carbon source; The weight ratio of the cellulose carbon source, the biodegradable polymer carbon source and the low molecular weight carbon source is 1.5-2.5:1-1.5:1; the wrapping material includes at least one of attapulgite or bentonite; In terms of weight, the carbon source agent for sewage treatment includes: 15 to 25 parts of cellulose carbon source, 12 to 18 parts of biodegradable polymer carbon source, 12 to 20 parts of binder, 8 to 15 parts of low molecular weight carbon source and 15 to 25 parts of packaging material.

2. The carbon source agent for sewage treatment according to claim 1, It is characterized in that The cellulose carbon source includes at least one of corn cobs, rice straws, reed straws, and chestnut shells.

3. The carbon source agent for sewage treatment according to claim 1, It is characterized in that The biodegradable polymer carbon source includes at least one of polycaprolactone, poly-β-hydroxybutyric acid, and polylactic acid.

4. The carbon source agent for sewage treatment according to claim 1, It is characterized in that The binder is starch.

5. The carbon source agent for sewage treatment according to claim 1, It is characterized in that The low molecular weight carbon source is at least one of sodium acetate, citric acid and fructose.

6. The carbon source agent for sewage treatment according to any one of claims 1 to 5, It is characterized in that In terms of weight, the carbon source agent for sewage treatment also includes 1 to 3 parts of sulfate and 20 to 40 parts of water.

7. The carbon source agent for sewage treatment according to claim 6, It is characterized in that The sulfate includes at least one of sodium sulfate and potassium sulfate.

8. A method for preparing the carbon source agent for sewage treatment as claimed in claim 6 or 7, It is characterized in that The method comprises the following preparation steps: Step S1, mixing the binder and part of the water for gelatinization, then adding the cellulose carbon source, the biodegradable polymer carbon source, the low molecular weight carbon source and the sulfate, stirring evenly, and granulating to obtain a carbon source solid matrix; Step S2: Mix the wrapping material with the remaining water, stir until viscous, and wrap it on the surface of the carbon source solid matrix, and dry it to obtain the product.

9. The preparation method according to claim 8, It is characterized in that The temperature of the gelatinization treatment is 60-70°C.

10. Use of the sewage treatment carbon source agent according to any one of claims 1 to 7 in sewage treatment.

Images