Method for treating machining wastewater

Abstract

This invention relates to a method for treating machining wastewater, belonging to the field of water treatment technology. The invention involves loading Gram-positive Staphylococcus aureus, a bacterium with grease-degrading capabilities, into the internal pores of an impregnated adsorption preform to prepare a self-made adsorption material. First, cetyltrimethylammonium bromide is added to the machining wastewater to reduce the oil-water interfacial tension and the strength and thickness of the oil-water interfacial film, causing the oil-containing emulsion to become unstable, thus achieving oil-water separation. Next, the self-made adsorption material is added to the wastewater. Utilizing the oleophilic adsorption properties of the adsorption preform, unstable oil droplets in the wastewater are enriched and adsorbed onto the preform. Then, the Staphylococcus aureus loaded inside the preform undergoes biodegradation, effectively improving the removal rate of grease pollutants in the machining wastewater. Finally, a flocculant is used to flocculate and settle the adsorbed grease and degraded solid particles, and the wastewater is filtered to complete the treatment of the machining wastewater.

Description

Technical Field

[0001] This invention relates to a method for treating wastewater from machining, belonging to the field of water treatment technology. Background Technology

[0002] Currently, emulsions in the machinery manufacturing industry, also known as coolants or lubricants, are mainly composed of mineral oil, surfactants, water, and chemical additives. In production applications, they are formulated in specific proportions according to actual needs. Emulsion wastewater has high levels of COD and oil pollutants, a pungent odor, poor biodegradability, and good oil-emulsion stability. It contains a large amount of surfactants, oily substances, and salts. Surfactants, with their amphiphilic properties, play a role in dispersing, emulsifying, and stabilizing in wastewater. The stable structure of emulsion wastewater is mainly based on reducing interfacial tension and forming a double electric layer, resulting in a very stable emulsion structure. Therefore, this type of wastewater is difficult to treat and has poor treatment effects.

[0003] In view of the above-mentioned shortcomings, the designer has actively researched and innovated in order to create a method for treating mechanical processing wastewater, making it more valuable for industrial use. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this invention is to provide a method for treating machining wastewater.

[0005] The present invention provides a method for treating machining wastewater, comprising the following specific steps:

[0006] (1) First, adjust the pH of the mechanical processing wastewater to be treated to 6-7, then add hexadecyltrimethylammonium bromide at a dosage of 200 mg / L, and after aeration for 40-50 min, add the self-made adsorbent material at a dosage of 10 g / L and continue aeration for 24-30 h.

[0007] (2) After the above reaction is completed, continue to add polyaluminum chloride at a dosage of 1000 mg / L for flocculation and precipitation. After reacting for 30 to 40 minutes, filter and separate to remove the filter residue. The resulting filtrate is the treated mechanical processing wastewater.

[0008] The self-made adsorbent material includes an adsorbent blank and microorganisms immobilized inside it;

[0009] The adsorbent preform is prepared by spray drying after compounding adsorbent powder, fluorosilicone emulsion and alkyl ketene dimer powder.

[0010] Furthermore, the microorganisms attached to the interior of the adsorbent blank are Staphylococcus aureus.

[0011] Furthermore, the adsorbent powder is prepared by crushing kaolin and zeolite molecular sieves, mixing and kneading them with sodium bicarbonate and microcrystalline wax, granulating them, and then calcining them at high temperature.

[0012] Furthermore, the preparation method of the self-made adsorbent material is as follows:

[0013] After sterilization, the adsorbent preform is mixed with a 30% chitosan solution at a mass ratio of 1:10 and impregnated for 10-12 hours. The residue obtained by filtration is the impregnated adsorbent preform. The impregnated adsorbent preform is then sterilized and added to a suspension of Staphylococcus aureus with a total viable count ≥5.0×10⁹ cfu / g. The suspension is then cultured at 30℃ and 120 r / min for 5 days with shaking to allow the microorganisms to adsorb and attach to the biofilm. Finally, the preform is freeze-dried under vacuum to obtain the self-made adsorbent material.

[0014] Furthermore, the method for preparing the adsorption preform is as follows:

[0015] By weight, 35-45 parts of fluorosilicone emulsion with a solid content of 35% are mixed with 20-25 parts of adsorbent powder to obtain an adsorbent emulsion. Alkyl ketene dimer powder is mixed with the adsorbent emulsion at a mass ratio of 1:1, and then spray-dried to obtain an adsorbent preform.

[0016] Furthermore, the preparation method of the adsorbent powder is as follows:

[0017] By weight, 45-50 parts of kaolin and 20-30 parts of zeolite molecular sieve are dried in an oven and then pulverized into 200-mesh powder in a pulverizer. Subsequently, they are mixed with 20-25 parts of sodium bicarbonate and 18-20 parts of microcrystalline wax and kneaded and granulated in a kneader. The resulting granules are placed in a muffle furnace, heated to 380-420°C, and calcined for 1-2 hours. After cooling, the granules are pulverized and sieved to obtain adsorbent powder.

[0018] By means of the above-described solution, the present invention has at least the following advantages:

[0019] (1) In this invention, sodium bicarbonate, microcrystalline wax and other materials are used to modify kaolin and zeolite molecular sieves, so that the resulting adsorbent powder has porous and hydrophobic properties, which is beneficial to oil-water separation.

[0020] (2) The adsorbent powder is compounded with fluorosilicone emulsion to obtain an organic adsorbent emulsion containing hydrophobic particles. The adsorbent is modified by the combined action of sodium polystyrene sulfonate and alkyl ketene dimer and spray-dried to obtain an adsorbent blank. The latex particles in the adsorbent emulsion, which are grafts, carry positive charges and are exposed on the surface of the adsorbent blank particles, which makes them more effective at adsorbing negatively charged oil droplets in the mechanical processing wastewater and improves the adsorption efficiency of the adsorbent blank.

[0021] (3) This invention loads Staphylococcus aureus, a Gram-positive bacterium with grease degradation function, into the pores inside an impregnated adsorption preform to prepare a self-made adsorption material. First, cetyltrimethylammonium bromide is added to the machining wastewater to be treated to reduce the interfacial tension and the strength and thickness of the oil-water interfacial film, so that the oil-containing emulsion is in an unstable state, achieving the purpose of oil-water separation. Then, the self-made adsorption material is added to the wastewater. Utilizing the oleophilic adsorption properties of the adsorption preform, the unstable oil droplets in the wastewater can be enriched and adsorbed onto the adsorption preform. Then, the Staphylococcus aureus loaded inside the preform undergoes biodegradation, which can effectively improve the removal rate of grease pollutants in machining wastewater. Finally, the adsorbed grease and degraded solid particles are flocculated and settled by flocculant, and the machining wastewater is treated by filtration.

[0022] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0023] The specific embodiments of the present invention will be described in further detail below with reference to the examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0024] (1) By weight, 45-50 parts of kaolin and 20-30 parts of zeolite molecular sieve are placed in an oven and dried. Then they are placed in a pulverizer and pulverized into 200-mesh powder. Then they are mixed with 20-25 parts of sodium bicarbonate and 18-20 parts of microcrystalline wax and kneaded in a kneader to granulate. The granules obtained by kneading are placed in a muffle furnace, heated to 380-420℃, calcined for 1-2 hours, cooled and removed, and then pulverized and sieved to obtain adsorbent powder.

[0025] This invention uses sodium bicarbonate, microcrystalline wax, etc. to modify kaolin and zeolite molecular sieves, so that the resulting adsorbent powder has porous and hydrophobic properties, which is beneficial to oil-water separation.

[0026] (2) By weight, 35-45 parts of fluorosilicone emulsion with a solid mass content of 35% are mixed with 20-25 parts of adsorbent powder to obtain an adsorbent emulsion. The alkyl ketene dimer powder is mixed with the adsorbent emulsion at a mass ratio of 1:1 and spray-dried to obtain an adsorbent blank.

[0027] The adsorbent powder was compounded with fluorosilicone emulsion to obtain an organic adsorbent emulsion containing hydrophobic particles. The emulsion was modified by the combined action of sodium polystyrene sulfonate and alkyl ketene dimer and then spray-dried to obtain an adsorbent preform. The latex particles in the adsorbent emulsion, which act as grafts, carry positive charges and are exposed on the surface of the adsorbent preform particles, thereby enhancing their adsorption capacity for negatively charged oil droplets in machining wastewater and improving the adsorption efficiency of the adsorbent preform.

[0028] (3) After sterilizing the above-mentioned adsorbent preform, mix it with a 30% chitosan solution at a mass ratio of 1:10 and impregnate for 10-12 hours. Filter and separate the residue to obtain the impregnated adsorbent preform. Sterilize the impregnated adsorbent preform and then add it to a solution with a total viable count ≥5.0×10⁻⁶. 9 The microorganisms were adsorbed and attached to a biofilm in a suspension of Staphylococcus aureus at CFU / g and cultured at 30°C and 120 rpm for 5 days. Finally, the microorganisms were freeze-dried under vacuum to obtain the self-made adsorbent material.

[0029] This invention loads Staphylococcus aureus, a Gram-positive bacterium with oil degradation function, into the internal pores of an impregnated adsorption preform to prepare a self-made adsorption material.

[0030] (4) First, adjust the pH of the mechanical processing wastewater to be treated to 6-7, then add hexadecyltrimethylammonium bromide at a dosage of 200 mg / L, aerate for 40-50 min, then add the self-made adsorbent material at a dosage of 10 g / L, and continue aeration for 24-30 h.

[0031] This invention first adds hexadecyltrimethylammonium bromide to the machining wastewater to reduce the interfacial tension and the strength and thickness of the oil-water interfacial film, causing the oil-containing emulsion to be in an unstable state, thus achieving the purpose of oil-water separation. Then, a self-made adsorbent material is added to the wastewater. Utilizing the oleophilic adsorption properties of the adsorbent preform, the unstable oil droplets in the wastewater can be enriched and adsorbed onto the adsorbent preform. Then, the Staphylococcus aureus loaded inside the preform undergoes biodegradation, which can effectively improve the removal rate of oil pollutants in machining wastewater.

[0032] (5) After the above reaction is completed, continue to add polyaluminum chloride at a dosage of 1000 mg / L for flocculation and precipitation. After reacting for 30 to 40 minutes, filter and separate to remove the filter residue. The resulting filtrate is the treated mechanical processing wastewater.

[0033] Finally, the adsorbed oils and degraded solid particles are flocculated and settled by flocculants, and the treated mechanical processing wastewater is completed after filtration.

[0034] Example 1

[0035] (1) By weight, 45 parts of kaolin and 20 parts of zeolite molecular sieve were placed in an oven to dry, and then pulverized into 200-mesh powder in a pulverizer. Then, they were mixed with 20 parts of sodium bicarbonate and 18 parts of microcrystalline wax and kneaded and granulated in a kneader. The granules obtained by kneading were placed in a muffle furnace, heated to 380°C, and calcined for 1 hour. After cooling, the granules were pulverized and sieved to obtain adsorbent powder.

[0036] (2) By weight, 35 parts of fluorosilicone emulsion with a solid mass content of 35% are mixed with 20 parts of adsorbent powder to obtain an adsorbent emulsion. The alkyl ketene dimer powder is mixed with the adsorbent emulsion at a mass ratio of 1:1 and spray-dried to obtain an adsorbent blank.

[0037] (3) After sterilizing the above-mentioned adsorbent preform, it is mixed with a 30% chitosan solution at a mass ratio of 1:10 and impregnated for 10 hours. The residue obtained by filtration is the impregnated adsorbent preform. The impregnated adsorbent preform is then sterilized and added to a solution with a total viable count ≥5.0×10⁻⁶. 9 The microorganisms were adsorbed and attached to a biofilm in a suspension of Staphylococcus aureus at CFU / g and cultured at 30°C and 120 rpm for 5 days. Finally, the microorganisms were freeze-dried under vacuum to obtain the self-made adsorbent material.

[0038] (4) First, adjust the pH of the mechanical processing wastewater to be treated to 6, then add hexadecyltrimethylammonium bromide at a dosage of 200 mg / L, aerate for 40 min, then add the self-made adsorbent material at a dosage of 10 g / L, and continue aeration for 24 h.

[0039] (5) After the above reaction is completed, continue to add polyaluminum chloride at a dosage of 1000 mg / L for flocculation and precipitation. After reacting for 30 minutes, filter and separate to remove the filter residue. The resulting filtrate is the treated machining wastewater.

[0040] Example 2

[0041] (1) By weight, 48 parts of kaolin and 25 parts of zeolite molecular sieve were placed in an oven to dry, and then pulverized into 200-mesh powder in a pulverizer. Subsequently, they were mixed with 23 parts of sodium bicarbonate and 19 parts of microcrystalline wax and kneaded and granulated in a kneader. The granules obtained by kneading were placed in a muffle furnace, heated to 400°C, and calcined for 2 hours. After cooling, the granules were pulverized and sieved to obtain adsorbent powder.

[0042] (2) By weight, 40 parts of fluorosilicone emulsion with a solid mass content of 35% are mixed with 23 parts of adsorbent powder to obtain an adsorbent emulsion. The alkyl ketene dimer powder is mixed with the adsorbent emulsion at a mass ratio of 1:1 and spray-dried to obtain an adsorbent blank.

[0043] (3) After sterilizing the above-mentioned adsorbent preform, it is mixed with a 30% chitosan solution at a mass ratio of 1:10 and impregnated for 11 hours. The residue obtained by filtration is the impregnated adsorbent preform. The impregnated adsorbent preform is then sterilized and added to a solution with a total viable count ≥5.0×10⁻⁶. 9 The microorganisms were adsorbed and attached to a biofilm in a suspension of Staphylococcus aureus at CFU / g and cultured at 30°C and 120 rpm for 5 days. Finally, the microorganisms were freeze-dried under vacuum to obtain the self-made adsorbent material.

[0044] (4) First, adjust the pH of the mechanical processing wastewater to be treated to 7, then add hexadecyltrimethylammonium bromide at a dosage of 200 mg / L, aerate for 45 min, then add the self-made adsorbent material at a dosage of 10 g / L, and continue aeration for 27 h.

[0045] (5) After the above reaction is completed, continue to add polyaluminum chloride at a dosage of 1000 mg / L for flocculation and precipitation. After reacting for 35 minutes, filter and separate to remove the filter residue. The resulting filtrate is the treated mechanical processing wastewater.

[0046] Example 3

[0047] (1) By weight, 50 parts of kaolin and 30 parts of zeolite molecular sieve were placed in an oven to dry, and then pulverized into 200-mesh powder in a pulverizer. Then, they were mixed with 25 parts of sodium bicarbonate and 20 parts of microcrystalline wax and kneaded and granulated in a kneader. The granules obtained by kneading were placed in a muffle furnace, heated to 420°C, and calcined for 2 hours. After cooling, the granules were pulverized and sieved to obtain adsorbent powder.

[0048] (2) By weight, 45 parts of fluorosilicone emulsion with a solid mass content of 35% are mixed with 25 parts of adsorbent powder to obtain an adsorbent emulsion. The alkyl ketene dimer powder is mixed with the adsorbent emulsion at a mass ratio of 1:1 and spray-dried to obtain an adsorbent blank.

[0049] (3) After sterilizing the above-mentioned adsorbent preform, it is mixed with a 30% chitosan solution at a mass ratio of 1:10 and impregnated for 12 hours. The residue obtained by filtration is the impregnated adsorbent preform. The impregnated adsorbent preform is then sterilized and added to a solution with a total viable count ≥5.0×10⁻⁶. 9 The microorganisms were adsorbed and attached to a biofilm in a suspension of Staphylococcus aureus at CFU / g and cultured at 30°C and 120 rpm for 5 days. Finally, the microorganisms were freeze-dried under vacuum to obtain the self-made adsorbent material.

[0050] (4) First, adjust the pH of the mechanical processing wastewater to be treated to 7, then add hexadecyltrimethylammonium bromide at a dosage of 200 mg / L, aerate for 50 min, then add the self-made adsorbent material at a dosage of 10 g / L, and continue aeration for 30 h.

[0051] (5) After the above reaction is completed, continue to add polyaluminum chloride at a dosage of 1000 mg / L for flocculation and precipitation. After reacting for 40 minutes, filter and separate to remove the filter residue. The resulting filtrate is the treated mechanical processing wastewater.

[0052] Compare with Example 1

[0053] The preparation method of this comparative example is basically the same as that of Example 1, except that the self-made adsorbent material of this invention is not added during treatment, while other wastewater treatment steps remain unchanged.

[0054] Compare with Example 2

[0055] The preparation method of this comparative example is basically the same as that of Example 1. The only difference is that the adsorbent preform is directly used instead of the self-made adsorbent material of the present invention during the treatment. Other wastewater treatment steps remain unchanged.

[0056] The processing effects of Examples 1-3 and Control Examples 1 and 2 of the present invention were tested respectively, and the specific test results are shown in Table 1:

[0057] Detection methods

[0058] Simulated machining wastewater with an oil content of 800 mg / L and a COD content of 40000 mg / L was treated using the wastewater treatment method of the present invention. After treatment, the oil removal rate and COD removal rate were measured.

[0059] Table 1 Performance Test Results

[0060] Testing items Oil removal rate (%) COD removal rate (%) Example 1 94 97 Example 2 95 98 Example 3 94 97 Compare with Example 1 80 82 Compare with Example 2 85 89

[0061] As can be seen from the test data in the table above, the treatment effect of machining wastewater in Examples 1-3 of the present invention is significant, which proves that the technical solution of this application is feasible.

[0062] Next, the test results of Comparative Examples 1 and 2 were compared with those of Example 1 of the present invention. Because Comparative Example 1 did not add the self-made adsorbent material of the present invention during treatment, and other wastewater treatment steps remained unchanged, the final wastewater treatment effect was significantly reduced. Comparative Example 2 directly used an adsorbent preform instead of the self-made adsorbent material of the present invention, resulting in a reduction in the final wastewater treatment effect. This confirms that the present invention uses sodium bicarbonate, microcrystalline wax, etc., to modify kaolin and zeolite molecular sieves, giving the resulting adsorbent powder porous and hydrophobic properties, which is beneficial for oil-water separation. The adsorbent powder is compounded with a fluorosilicone emulsion to obtain an organic adsorbent emulsion containing hydrophobic particles. This emulsion is then modified under the combined action of sodium polystyrene sulfonate and alkyl ketene dimers, and spray-dried to obtain an adsorbent preform. The latex particles in the adsorbent emulsion, acting as grafts, carry a positive charge and are exposed on the surface of the adsorbent preform particles, enabling them to adsorb the negatively charged oil in the machining wastewater. The adsorption capacity of the droplets is enhanced, improving the adsorption efficiency of the adsorption blank. This invention loads Staphylococcus aureus, a Gram-positive bacterium with oil degradation function, into the internal pores of the impregnated adsorption blank to prepare a self-made adsorption material. First, cetyltrimethylammonium bromide is added to the machining wastewater to be treated to reduce the interfacial tension and the strength and thickness of the oil-water interfacial film, causing the oil-containing emulsion to be in an unstable state, thus achieving the purpose of oil-water separation. Then, the self-made adsorption material is added to the wastewater. Utilizing the oleophilic adsorption properties of the adsorption blank, the unstable oil droplets in the wastewater can be enriched and adsorbed onto the adsorption blank. Then, the Staphylococcus aureus loaded inside the blank undergoes biodegradation, which can effectively improve the removal rate of oil pollutants in the machining wastewater. Finally, the adsorbed oil and degraded solid particles are flocculated and settled by flocculant, and the machining wastewater is treated by filtration.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for treating machining wastewater, characterized in that... The specific processing steps are as follows: (1) First, adjust the pH of the mechanical processing wastewater to be treated to 6-7, then add hexadecyltrimethylammonium bromide at a dosage of 200 mg / L, and after aeration for 40-50 min, add the self-made adsorbent material at a dosage of 10 g / L and continue aeration for 24-30 h. (2) After the above reaction is completed, continue to add polyaluminum chloride at a dosage of 1000 mg / L for flocculation and precipitation. After reacting for 30 to 40 minutes, filter and separate to remove the filter residue. The resulting filtrate is the treated mechanical processing wastewater. The preparation method of the self-made adsorbent material is as follows: After sterilization, the adsorbent preform is mixed with a 30% chitosan solution at a mass ratio of 1:10 and impregnated for 10-12 hours. The filter residue is obtained by filtration, which is the impregnated adsorbent preform. The impregnated adsorbent preform is then sterilized and added to a suspension of Staphylococcus aureus with a total viable count ≥5.0×10⁹ cfu / g. The suspension is then shaken and cultured at 30℃ and 120 r / min for 5 days to allow microorganisms to adsorb and attach to the biofilm. Finally, the preform is freeze-dried under vacuum to obtain the self-made adsorbent material. The method for preparing the adsorption preform is as follows: By weight, 35-45 parts of fluorosilicone emulsion with a solid content of 35% are mixed with 20-25 parts of adsorbent powder to obtain an adsorbent emulsion. Alkyl ketene dimer powder is mixed with the adsorbent emulsion at a mass ratio of 1:1 and spray-dried to obtain an adsorbent preform. The adsorbent powder is prepared by crushing kaolin and zeolite molecular sieves, mixing and kneading them with sodium bicarbonate and microcrystalline wax, granulating them, and then calcining them at high temperature.

2. The method for treating machining wastewater according to claim 1, characterized in that: The preparation method of the adsorbent powder is as follows: By weight, 45-50 parts of kaolin and 20-30 parts of zeolite molecular sieve are dried in an oven and then pulverized into 200-mesh powder in a pulverizer. Subsequently, they are mixed with 20-25 parts of sodium bicarbonate and 18-20 parts of microcrystalline wax and kneaded and granulated in a kneader. The resulting granules are placed in a muffle furnace, heated to 380-420°C, and calcined for 1-2 hours. After cooling, the granules are pulverized and sieved to obtain adsorbent powder.