Deep dehydration treatment process for oil-containing scum

Abstract

The deep dehydration treatment process comprises the following steps: carrying out alkalization treatment, carrying out ultrasonic demulsification, carrying out thermal sedimentation to realize water-oil separation, carrying out oxidative degradation on a water phase and then discharging the water phase, and distilling an oil phase and then recovering an oil layer. According to the developed scum treatment process, oil-containing scum can be reduced through dehydration, under the synergistic effect of ultrasonic waves and the dehydrating agent, the water content of bottom mud obtained after scum treatment can be reduced to 12%, the dehydration efficiency is high, after water-oil separation is conducted on the treated scum, a water phase is subjected to oxidative degradation, and an oil phase is subjected to distillation recovery, so that the water-oil separation effect is good. The water-phase COD removal rate is high and reaches the national emission standard, the oil-phase recovery rate is high, resource recycling is achieved, and good economic and social benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of environmental pollution treatment agents, and in particular to a deep dehydration treatment process for oily scum. Background Art

[0002] Oily scum refers to the oily sludge produced when oil droplets and solid particles in the water are attached to tiny air bubbles and carried to the water surface after flocculants are added in the flotation section of the wastewater treatment process of petrochemical enterprises. It is mainly composed of negatively charged hydrophilic colloidal particles, with complex composition and difficult to dehydrate. As the quality of crude oil deteriorates, the amount of scum will increase significantly. At present, enterprises generally mix scum with other oil sludge and add flocculants. After mechanical separation and dehydration, the water content is reduced to about 85% and then landfilled as hazardous waste. Due to the serious emulsification of scum, the dehydration effect of the existing process is limited, and crude oil recovery is difficult, which not only increases the burden of hazardous waste treatment for enterprises, but also wastes crude oil resources.

[0003] There are three main methods for demulsification of scum, namely physical method, chemical method and biological method. Among them, the physical method mainly includes gravity sedimentation method, centrifugal separation method, filtration method, electric field method, microwave radiation method, ultrasonic method and membrane demulsification method; the chemical method mainly includes demulsifier addition method. If you want to deeply treat the oily scum with complex components, it is difficult to achieve the ideal effect by relying on a single treatment method. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention aims to use an oil-containing scum dehydrating agent composed of a demulsifier, a flocculant and a surfactant in combination with ultrasonic wave to deeply dehydrate the scum.

[0005] To achieve the above object, the present invention provides the following technical solutions: A deep dehydration treatment process containing scum, comprising the following steps: 1. Pass the scum into the pH adjustment tank, add sodium carbonate into the tank for alkalization treatment, and adjust the pH to 7-7.5; 2. The scum after pH adjustment is passed into the ultrasonic treatment tank, a dehydrating agent is added into the tank, the temperature is raised to 40-60°C, and the emulsion is broken under the action of the ultrasonic standing wave field; 3. After ultrasonic treatment, the scum enters the waste oil sedimentation tank for thermal sedimentation to achieve water-oil separation; Fourth, the water layer is cut and passed into an oxidation degradation tank, hydrogen peroxide is added to the water phase for oxidation degradation and then discharged; the oil phase is passed into a distillation tank, and the oil layer is recovered after distillation; Wherein, the oily scum dehydrating agent comprises, by mass percentage: 50~70% multi-branched demulsifier, 20~40% diquaternary ammonium salt surfactant, 10% flocculant and the rest water; The multi-branched demulsifier is firstly prepared by using triethylenetetramine as a reaction initiator and methyl acrylate as a monomer through Michael addition reaction and amidation reaction to obtain a hyperbranched polyamide-amine; then, propylene oxide, ethylene oxide and propylene oxide are sequentially added under alkaline conditions to polymerize to obtain a multi-branched polyether demulsifier; The diquaternary ammonium salt surfactant uses rhamnolipid as a starting material, uses its terminal carboxyl group to first undergo chlorination reaction, then introduces amino groups through amidation reaction, and then forms a double-headed quaternary ammonium salt with ammonium bromide.

[0006] Furthermore, the preparation process of the multi-branched demulsifier is as follows: 1) Add a certain amount of triethylenetetramine to the reaction bottle, add methanol as a solvent and stir to mix evenly, then slowly drop an equal molar amount of methyl acrylate in an ice water bath and under nitrogen protection, heat to 35°C after the addition is complete, stir and react for 48 h; then heat to 60, 80, 100, 120, 140 in stages, react for 2 h respectively, and evacuate during the reaction, and the obtained viscous liquid is the hyperbranched polyamide-amine; 2) Add the hyperbranched polyamide-amine into the reaction kettle, add a catalytic amount of potassium hydroxide, evacuate, raise the temperature to 120°C, and then slowly introduce propylene oxide. When the pressure of the kettle drops to negative pressure and stabilizes, introduce ethylene oxide and propylene oxide into the kettle in sequence, and react at a constant temperature until the pressure of the kettle drops to negative pressure and stabilizes.

[0007] Furthermore, in the step 2), the amounts of raw materials added are: 1 part of hyperbranched polyamide-amine, 10 parts of propylene oxide, 200 parts of ethylene oxide, and 200 parts of propylene oxide.

[0008] Furthermore, the preparation process of the diquaternary ammonium salt surfactant is as follows: S1. Add rhamnolipid and a catalytic amount of DMAP into a reaction flask, add thionyl chloride dropwise to carry out chlorination reaction, and dissolve the product after the reaction in dichloromethane and place in an ice water bath for standby use; S2, dissolving 6-aminocaproic acid methyl ester hydrochloride and triethylamine in dichloromethane, and then slowly adding them dropwise to step S1, heating to 30°C after the addition, stirring and reacting for 24 hours, adding sodium hydroxide solution, collecting the organic phase, drying and filtering, and the product is ready for use; S3, dissolving the product of step S2 in dichloromethane and placing it in an ice-water bath, slowly adding 3-dimethylaminopropylamine dropwise under nitrogen protection, moving to room temperature after the addition is complete, and continuing to stir the reaction for 24 hours, and distilling under reduced pressure to obtain a viscous liquid; S4, dissolving the viscous liquid in step S3 in ethanol, then adding 3-bromo-propyltrimethylammonium bromide, heating to 90° C. and stirring for 24 h, cooling to room temperature, distilling under reduced pressure to remove the solvent, recrystallizing with a mixed solution of ethanol and acetone, and drying to obtain the product.

[0009] Furthermore, the flocculant is cationic polyacrylamide.

[0010] Furthermore, in the step 2, the amount of the dehydrating agent added is 5-10 mg / L.

[0011] Furthermore, in step 2, the ultrasonic conditions are: ultrasonic frequency 20-40 kHz, power 200-400 W, and ultrasonic time 5-7 min.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The scum treatment process developed by the present invention can reduce the amount of oil-containing scum by dehydration. Under the synergistic effect of ultrasound and a dehydrating agent, the moisture content of the sludge after the scum treatment can be reduced to 12%, and the dehydration efficiency is high. After the treated scum is separated from water and oil, the water phase is oxidized and degraded and the oil phase is distilled and recovered. The COD removal rate of the water phase is high and meets the national emission standards. The high recovery rate of the oil phase realizes resource recycling and has good economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The scum microscope photos before and after ultrasonic demulsification are shown in Figure 1. a is the photo before ultrasonic demulsification, and b is the photo after ultrasonic demulsification. Figure 2 It is the diagram of sediment moisture content under different ultrasonic powers; Figure 3 It is the diagram of sediment moisture content under different treatment temperatures; Figure 4 This is a diagram of the moisture content of sediment after treatment with different dehydrating agents. DETAILED DESCRIPTION

[0014] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0016] Example: This application takes the oil-containing scum in the flotation section of Yangzhou Petrochemical as the research object. After on-site sampling and analysis, the scum in the flotation section of this enterprise has a water content of 97%, an oil content of 1.2%, a pH of 6.4, a volume average particle size of 28.3 μm, and a specific surface area of ​​0.62 m 2 / g.

[0017] The above scum is deeply dehydrated in the following steps: 1. Pass the scum into the pH adjustment tank, add sodium carbonate into the tank for alkalization treatment, and adjust the pH to 7-7.5; 2. After adjusting the pH, the scum is passed into the ultrasonic treatment tank, 5-10 mg / L of dehydrating agent is added into the tank, the temperature is raised to 40-60°C, and the emulsion is broken under the action of the ultrasonic standing wave field; the ultrasonic frequency is 20-40 kHz, the power is 200-400 W, and the ultrasonic time is 5-7 minutes; 3. After ultrasonic treatment, the scum enters the waste oil sedimentation tank for thermal sedimentation to achieve water-oil separation; Fourth, the water layer is cut and passed into an oxidation degradation tank, hydrogen peroxide is added to the water phase for oxidation degradation and then discharged; the oil phase is passed into a distillation tank, and the oil layer is recovered after distillation; The oily scum dehydrating agent comprises, by mass percentage, 50-70% of a multi-branched demulsifier, 20-40% of a diquaternary ammonium salt surfactant, and 10% of a flocculant.

[0018] Adjust the mass ratio to obtain the following dehydrating agent sample: Sample 1: 50% multi-branched demulsifier, 30% diquaternary ammonium surfactant, 10% flocculant and 10% water; Sample 2: 50% multi-branched demulsifier, 20% diquaternary ammonium surfactant, 10% flocculant and 20% water; Sample 3: 60% multi-branched demulsifier, 20% diquaternary ammonium surfactant, 10% flocculant and 10% water; In the above samples, the multi-branched demulsifier is first prepared from triethylenetetramine as a reaction initiator and methyl acrylate as a monomer through Michael addition reaction and amidation reaction to obtain a hyperbranched polyamide-amine; then propylene oxide, ethylene oxide, and propylene oxide are added in sequence under alkaline conditions to polymerize to obtain a multi-branched polyether demulsifier.

[0019] The specific preparation process is as follows: 1) Add a certain amount of triethylenetetramine to the reaction bottle, add methanol as a solvent and stir to mix evenly, then slowly drop an equal molar amount of methyl acrylate in an ice water bath and under nitrogen protection, heat to 35°C after the addition is complete, stir and react for 48 h; then heat to 60, 80, 100, 120, 140 in stages, react for 2 h respectively, and evacuate during the reaction, and the obtained viscous liquid is the hyperbranched polyamide-amine; 2) Add 1 part of hyperbranched polyamide-amine into the reaction kettle, add a catalytic amount of potassium hydroxide, evacuate, raise the temperature to 120°C, and then slowly introduce 10 parts of propylene oxide. When the pressure of the kettle drops to negative pressure and stabilizes, introduce 200 parts of ethylene oxide and 200 parts of propylene oxide into the kettle in sequence, and react at a constant temperature until the pressure of the kettle drops to negative pressure and stabilizes.

[0020] In the above samples, the diquaternary ammonium salt surfactant uses rhamnolipid as the starting material, first uses its terminal carboxyl group to undergo chlorination reaction, then introduces the amino group through amidation reaction, and then forms a double-headed quaternary ammonium salt with ammonium bromide salt.

[0021] The specific preparation process is as follows: S1. Add rhamnolipid and a catalytic amount of DMAP into a reaction flask, add thionyl chloride dropwise to carry out chlorination reaction, and dissolve the product after the reaction in dichloromethane and place in an ice water bath for standby use; S2, dissolving 6-aminocaproic acid methyl ester hydrochloride and triethylamine in dichloromethane, and then slowly adding them dropwise to step S1, heating to 30°C after the addition, stirring and reacting for 24 hours, adding sodium hydroxide solution, collecting the organic phase, drying and filtering, and the product is ready for use; S3, dissolving the product of step S2 in dichloromethane and placing it in an ice-water bath, slowly adding 3-dimethylaminopropylamine dropwise under nitrogen protection, moving to room temperature after the addition is complete, and continuing to stir the reaction for 24 hours, and distilling under reduced pressure to obtain a viscous liquid; S4, dissolving the viscous liquid in step S3 in ethanol, then adding 3-bromo-propyltrimethylammonium bromide, heating to 90° C. and stirring for 24 h, cooling to room temperature, distilling under reduced pressure to remove the solvent, recrystallizing with a mixed solution of ethanol and acetone, and drying to obtain the product.

[0022] For comparison, based on sample 1, the multi-branched demulsifier was replaced with PEO-PPO-PEO to obtain control sample 1; and the diquaternary ammonium salt surfactant was replaced with rhamnolipid to obtain control sample 2.

[0023] Embodiment 1: 1. Pass the scum into the pH adjustment tank, add sodium carbonate into the tank for alkalization treatment, and adjust the pH to 7.25; 2. The scum after pH adjustment is passed into the ultrasonic treatment tank, 10 mg / L of dehydrating agent sample 1 is added into the tank, the temperature is raised to 50°C, and demulsification is carried out under the action of ultrasonic standing wave field; the ultrasonic frequency is fixed at 20 kHz, the ultrasonic power is adjusted to 100-600W, and the ultrasonic time is 5 min; 3. After ultrasonic treatment, the scum enters the waste oil sedimentation tank for thermal sedimentation to achieve water-oil separation; the water content of the sludge is tested, and the determination of the water content refers to GB / T 260-2016 "Determination of water content of petroleum products - Distillation method"; Fourth, the water layer is cut off and passed into an oxidation degradation tank, hydrogen peroxide is added to the water phase for oxidation degradation and then discharged; the oil phase is passed into a distillation tank and the oil layer is recovered after distillation.

[0024] The moisture content of the sediment at different ultrasonic powers in Example 1 is as follows: Figure 2 As shown in the figure, with the increase of acoustic power, the water content of the scum after treatment first decreases and then increases. There is an optimal value of ultrasonic power in the process of ultrasonic dehydration. Figure 1 As shown in the figure, the oil droplets and solid particles in the scum before treatment were of different sizes and randomly dispersed in the water phase. The emulsified oil was in the form of O / W, with some particles suspended in the continuous water phase and the other part wrapped inside the oil droplets. The water content of the sludge dropped to 38% after adding only demulsifier without ultrasound. After ultrasonic demulsification treatment, the oil droplet size increased significantly, small oil droplets collided, condensed and aggregated into large oil droplets, and most of the solid suspended particles were wrapped by oil droplets and separated from the continuous water phase. The water phase was clearer than before treatment. With the increase of acoustic power, the corresponding ultrasonic sound intensity also increased. When the ultrasonic sound intensity exceeded the cavitation threshold, cavitation would occur, forming a new emulsification of the waste oil, which increased the difficulty of dehydrating the waste oil. The results show that the water content of the sludge decreased significantly when the ultrasonic power was controlled at 200~400 W, and the best effect was achieved at 300 W.

[0025] Table 1 Embodiment 2: 1. Pass the scum into the pH adjustment tank, add sodium carbonate into the tank for alkalization treatment, and adjust the pH to 7.25; 2. The scum after pH adjustment is passed into the ultrasonic treatment tank, 10 mg / L of dehydrating agent sample 1 is added into the tank, the temperature is adjusted to 40-70°C, and demulsification is carried out under the action of ultrasonic standing wave field; the ultrasonic frequency is fixed at 20 kHz, the ultrasonic power is adjusted to 300W, and the ultrasonic time is 5 min; 3. After ultrasonic treatment, the scum enters the waste oil sedimentation tank for thermal sedimentation to achieve water-oil separation; the water content of the sludge is tested, and the determination of the water content refers to GB / T 260-2016 "Determination of water content of petroleum products - Distillation method"; Fourth, the water layer is cut off and passed into an oxidation degradation tank, hydrogen peroxide is added to the water phase for oxidation degradation and then discharged; the oil phase is passed into a distillation tank and the oil layer is recovered after distillation.

[0026] The moisture content of the bottom mud at different treatment temperatures in Example 2 is as follows: Figure 3 As shown, the results show that when the temperature is controlled at 50~60℃, the moisture content of the sediment decreases significantly, and the effect is best at 55℃, with a high dehydration rate.

[0027] As the ultrasonic temperature increases, the viscosity of the scum decreases. Under the action of ultrasonic mechanical vibration, the movement of the oil droplets intensifies, the number of collisions and aggregations between the oil droplets increases, and large oil droplets are quickly formed, which improves the dehydration effect. At the same time, the increase in temperature will lead to a decrease in the film stability and mechanical strength of the oil-water interface, making it easier to achieve the aggregation of oil droplets. The scum dehydration rate gradually decreases at high temperatures. This is because at low temperatures, the ultrasonic cavitation effect increases with the increase in temperature, and the dehydration effect is improved; after exceeding the critical temperature point of the sample, the sound intensity and cavitation effect of the ultrasonic wave will gradually weaken, making the dehydration effect worse.

[0028] Embodiment 3: 1. Pass the scum into the pH adjustment tank, add sodium carbonate into the tank for alkalization treatment, and adjust the pH to 7.25; 2. The scum after pH adjustment was passed into the ultrasonic treatment tank, 10 mg / L of dehydrating agent (samples 1-3 and control samples 1-2) was added into the tank, the temperature was adjusted to 55°C, and demulsification was carried out under the action of ultrasonic standing wave field; the ultrasonic frequency was fixed at 20kHz, the ultrasonic power was adjusted to 300 W, and the ultrasonic time was 5 min; 3. After ultrasonic treatment, the scum enters the waste oil sedimentation tank for thermal sedimentation to achieve water-oil separation; the water content of the sludge is tested. The determination of the water content refers to GB / T 260-2016 "Determination of water content of petroleum products - Distillation method"; Fourth, the water layer is cut off and passed into an oxidation degradation tank, hydrogen peroxide is added to the water phase for oxidation degradation and then discharged; the oil phase is passed into a distillation tank and the oil layer is recovered after distillation.

[0029] The moisture content of the sludge after treatment with different dehydrating agents in Example 3 is as follows: Figure 4 As shown, the results show that the dehydration effect of samples 1-3 of the present application is much better than that of control samples 1 and 2.

[0030] The composition of the oily scum in the refinery is complex, and it is difficult to achieve an ideal dehydration effect using a single demulsifier or flocculant. The present application prepares a double-headed quaternary ammonium salt surfactant and a multi-branched polyether demulsifier, which are combined with a cationic polyacrylamide flocculant to form a dehydrating agent, which has a high dehydration efficiency when used to treat oily scum. Firstly, cationic polyacrylamide is used as a flocculant to flocculate the sludge in the scum to form loose small flocs for removal; the diquaternary ammonium surfactant is obtained by modifying the biosurfactant rhamnolipid as the starting material. Rhamnolipid is biodegradable and has a certain demulsification effect. Through modification, a double-headed quaternary ammonium salt is grafted on its surface, which has a high solubility and an adsorption bridging effect, further promoting the flocculation effect; the multi-branched demulsifier is based on a hyperbranched polyamide-amine polymer, using the amino groups on its chain as active sites to polymerize to form a PEO-PPO-PEO chain, and multiple branched polyether chains are diffused on the structure of the hyperbranched polymer chain, which is more conducive to contact with the surface of the oil droplet in three-dimensional space. Under the synergistic effect of the diquaternary ammonium surfactant in reducing the strength of the interfacial film, it can also be more quickly dispersed to the oil-water interface, promote the aggregation of oil droplets, improve the demulsification efficiency, and promote oil-water separation.

[0031] In addition, the present application further tested the treatment effects of the water phase degradation and the oil phase distillation in step 4. The results showed that the treatment process provided by the present application achieved a COD removal rate of more than 95% in the water phase finally discharged after scum treatment, and an oil phase recovery rate of more than 97%, completing environmental governance and resource recovery. This technology can be used and promoted as an effective treatment method for scum dehydration in refineries to save energy and protect the environment.

[0032] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A deep dehydration process containing scum, characterized in that: The steps include:

1. Pass the scum into the pH adjustment tank, add sodium carbonate into the tank for alkalization treatment, and adjust the pH to 7-7.5; 2. The scum after pH adjustment is passed into the ultrasonic treatment tank, a dehydrating agent is added into the tank, the temperature is raised to 40-60°C, and the emulsion is broken under the action of the ultrasonic standing wave field; 3. After ultrasonic treatment, the scum enters the waste oil sedimentation tank for thermal sedimentation to achieve water-oil separation; Fourth, the water layer is cut and passed into the oxidation degradation tank, hydrogen peroxide is added to the water phase for oxidation degradation and then discharged; The oil phase is passed into a distillation tank, and the oil layer is recovered after distillation; Wherein, the oily scum dehydrating agent comprises, by mass percentage: 50~70% multi-branched demulsifier, 20~40% diquaternary ammonium salt surfactant, 10% flocculant and the rest water; The multi-branched demulsifier is firstly prepared by using triethylenetetramine as a reaction initiator and methyl acrylate as a monomer through Michael addition reaction and amidation reaction to obtain a hyperbranched polyamide-amine; then, propylene oxide, ethylene oxide and propylene oxide are sequentially added under alkaline conditions to polymerize to obtain a multi-branched polyether demulsifier; The diquaternary ammonium salt surfactant uses rhamnolipid as a starting material, uses its terminal carboxyl group to first undergo chlorination reaction, then introduces amino groups through amidation reaction, and then forms a double-headed quaternary ammonium salt with ammonium bromide.

2. The deep dehydration treatment process containing scum according to claim 1, characterized in that: The preparation process of the multi-branched demulsifier is as follows: 1) Add a certain amount of triethylenetetramine to a reaction bottle, add methanol as a solvent and stir to mix evenly, then slowly drop an equal molar amount of methyl acrylate in an ice water bath and under nitrogen protection, heat to 35°C after the dropwise addition is complete, stir and react for 48 hours; then heat to 60, 80, 100, 120, 140 in stages, react for 2 hours respectively, and evacuate during the reaction, and the obtained viscous liquid is the hyperbranched polyamide-amine; 2) Add the hyperbranched polyamide-amine into the reaction kettle, add a catalytic amount of potassium hydroxide, evacuate, raise the temperature to 120°C, and then slowly introduce propylene oxide. When the pressure of the kettle drops to negative pressure and stabilizes, introduce ethylene oxide and propylene oxide into the kettle in sequence, and react at a constant temperature until the pressure of the kettle drops to negative pressure and stabilizes.

3. The deep dehydration treatment process containing scum according to claim 2, characterized in that: In the step 2), the amounts of raw materials added are: 1 part of hyperbranched polyamide-amine, 10 parts of propylene oxide, 200 parts of ethylene oxide, and 200 parts of propylene oxide.

4. The deep dehydration treatment process containing scum according to claim 1, characterized in that: The preparation process of the diquaternary ammonium salt surfactant is as follows: S1. Add rhamnolipid and a catalytic amount of DMAP into a reaction flask, add thionyl chloride dropwise to carry out chlorination reaction, and dissolve the product after the reaction in dichloromethane and place in an ice water bath for standby use; S2, dissolving 6-aminocaproic acid methyl ester hydrochloride and triethylamine in dichloromethane, and then slowly adding them dropwise to step S1, heating to 30°C after the addition, stirring and reacting for 24 hours, adding sodium hydroxide solution, collecting the organic phase, drying and filtering, and the product is ready for use; S3, dissolving the product of step S2 in dichloromethane and placing it in an ice-water bath, slowly adding 3-dimethylaminopropylamine dropwise under nitrogen protection, moving to room temperature after the addition is complete, and continuing to stir the reaction for 24 hours, and distilling under reduced pressure to obtain a viscous liquid; S4, dissolving the viscous liquid in step S3 in ethanol, then adding 3-bromo-propyltrimethylammonium bromide, heating to 90° C. and stirring for 24 h, cooling to room temperature, distilling under reduced pressure to remove the solvent, recrystallizing with a mixed solution of ethanol and acetone, and drying to obtain the product.

5. The deep dehydration treatment process containing scum according to claim 1, characterized in that: The flocculant is cationic polyacrylamide.

6. The deep dehydration treatment process containing scum according to claim 1, characterized in that: In the step 2, the amount of the dehydrating agent added is 5-10 mg / L.

7. The deep dehydration treatment process containing scum according to claim 1, characterized in that: In the step 2, the ultrasonic conditions are: ultrasonic frequency 20-40 kHz, power 200-400 W, and ultrasonic time 5-7 min.

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