Intermittent sewage treatment system for oil product wharf

Abstract

The invention belongs to the technical field of oil product wharf sewage treatment, and relates to an oil product wharf intermittent sewage treatment system, which comprises a wastewater storage tank, a comprehensive regulation tank, an air flotation device, an intermediate water tank, a filler filter and a reclaimed water tank which are sequentially connected through pipelines, filler of the filler filter is a mixture of modified activated carbon and modified walnut shells, and the mass ratio of the modified activated carbon to the modified walnut shells is (0.5-2): 1. The filler of the filler filter can remove pollutants such as COD (Chemical Oxygen Demand), ammonia nitrogen, phosphorus, petroleum and the like in oil-containing sewage to the maximum extent, so that the quality of tail water is improved; the composite material is high in mechanical strength, not easy to wear, capable of effectively adsorbing organic matters in sewage for a long time and relatively long in service cycle; the intermittent full-physical treatment system is adopted, the operation load and cost are reduced, the operation and maintenance cost is low, energy is saved, consumption is reduced, the use of chemical reagents is reduced to the minimum, and the treatment effect is good.

Description

Technical Field

[0001] The invention belongs to the technical field of oil terminal sewage treatment, and in particular relates to an intermittent sewage treatment system for an oil terminal. Background Art

[0002] The cargo types of the oil terminal are mainly crude oil, various finished oil products, and edible oil. The production wastewater that needs to be treated in the area is mainly rainwater, oil tank cleaning water and polluted wastewater, polluted ground washing water, and laboratory wastewater. The wastewater of the oil terminal has a high sludge content, high chemical oxygen demand (COD), low biochemical oxygen demand (BOD), and poor biodegradability.

[0003] The existing filler filters for treating oil terminal sewage generally use activated carbon or walnut shell as a single material as filler. The activated carbon filler has high adsorption capacity, strong adaptability, small footprint, recyclability, and can remove heavy metals, but it has the disadvantages of low hardness, poor wear resistance, easy secondary pollution caused by admixtures, and high treatment costs. Although the walnut shell filler has high hardness, wear resistance, and is not easy to rot or agglomerate, it has good chemical stability, but it is not easy to treat oily sewage. In order to improve the oil removal effect of walnut shell filler, some inventors have modified walnut shells, such as Chinese invention patents CN 106422520 B and CN105498358 B, but the treatment of pollutants in oily sewage is not comprehensive enough, and its performance needs to be further improved. In addition, because the amount of wastewater treatment water is affected by the amount of rainfall, it is not suitable for continuous sewage treatment.

[0004] Therefore, it is necessary to further improve the performance of packing filters, adopt intermittent sewage treatment systems, reduce operating loads and costs, reduce operating and maintenance costs, save energy and reduce consumption, and reduce the use of chemical reagents. Summary of the invention

[0005] In view of the above-mentioned prior art, the present invention provides an intermittent sewage treatment system for an oil terminal, and the specific technical scheme is as follows: An intermittent sewage treatment system for an oil terminal comprises a wastewater storage tank, a comprehensive regulating tank, an air flotation device, an intermediate water tank, a filler filter and a middle water tank which are sequentially connected by pipelines; The filler of the filler filter is a mixture of modified activated carbon and modified walnut shell, and the mass ratio of the modified activated carbon to the modified walnut shell is (0.5-2):1; The modified activated carbon is obtained by treating activated carbon particles with calcination, acetic acid, polyaluminum sulfate and potassium hydrogen phthalate; the modified walnut shell is obtained by treating walnut shell fragments with ion water boiling, calcination, sodium hypochlorite and a mixed solution of polyacrylamide and ferric chloride.

[0006] The wastewater storage tank of the present invention is used to store oil tank cleaning water, polluted wastewater, polluted ground flushing water and laboratory wastewater, etc., and plays a role in regulating water volume and balancing water quality; the sewage in the wastewater storage tank is discharged to a comprehensive regulating tank for physical precipitation and further regulation, and the regulated sewage enters an air flotation device; the air flotation device mainly removes suspended matter and organic matter in the sewage, so as to achieve the purpose of water purification, and the treated sewage enters an intermediate water tank; the intermediate water tank plays a role in balancing the water volume, and then the sewage enters a packing filter; the packing filter deeply adsorbs, reacts and filters pollutants such as COD, ammonia nitrogen, total phosphorus and the like in the oily sewage, and can be used in single-stage or double-stage series according to water quality requirements; the effluent filtered by the packing filter enters a middle water tank, and is discharged or reused after being tested to meet the standards.

[0007] The modified activated carbon of the present invention has larger porosity and specific surface area, more adsorption sites, and increases the surface oxygen-containing functional groups and introduces phenyl groups to improve the adsorption capacity of aromatic organic matter in sewage, thereby further reducing the COD in sewage; the modified walnut shell is more porous and has stronger adsorption, and increases the hydrophilic groups, which are firmly combined with organic matter in sewage by forming hydrogen bonds, thereby significantly improving the adsorption effect of hydrophilic organic-based heavy metal ions in sewage, and using ferric chloride to improve the performance of the modified walnut shell to improve the adsorption effect of sulfur. The modified filler obtained by modifying the activated carbon and the walnut shell and then mixing them has strong adsorption capacity and pressure resistance, stable chemical properties (not easy to dissolve in acid and alkali solutions), high hardness, good wear resistance, good hydrophilicity, oil immersion resistance, and can be backwashed and regenerated, does not need to be replaced for long-term use, and has strong adsorption and pollution interception capacity (adsorption rate 25-53%); and the modified filler of the present invention has a specific gravity slightly greater than that of water, and is convenient for backwashing and regeneration. Its greatest feature is that it directly uses pre-filtration water for backwashing without the need for an air source and additional chemical agents, has low operating cost, convenient management, low backwashing intensity, good effect, and the filter material is not easy to rot and is durable.

[0008] Furthermore, the preparation method of the modified activated carbon comprises the following steps: A1. Under nitrogen protection, calcine the activated carbon particles of 100-150 mesh at 300-400℃ for 2-4 hours; A2. Place the calcined activated carbon particles in acetic acid, stir at 40-50°C for 2.5-3.5 hours, filter, and dry in a vacuum drying oven to constant weight; A3, placing the activated carbon particles treated in step A2 into a 6-10wt% polyaluminium sulfate solution, stirring at 40-50°C for 2.5-3.5 hours, filtering, and drying in a vacuum drying oven to constant weight; A4. Place the activated carbon particles treated in step A3 into a 0.1 mol / L potassium hydrogen phthalate solution, ultrasonically treat for 2-3 hours at 40-50°C, filter, and dry in a vacuum drying oven to constant weight.

[0009] Furthermore, the preparation method of the modified walnut shell comprises the following steps: B1. Add walnut shell particles crushed to 100-150 mesh into boiling deionized water and heat to boil for 50-70 minutes; then calcine the walnut shell particles at 300-400° C. for 2-4 hours under nitrogen protection; B2. Place the calcined walnut shell particles into a sodium hypochlorite solution with a concentration of 8-12 wt%, ultrasonically treat at 40-50° C. for 2-3 hours, filter, and dry in a vacuum drying oven to constant weight; B3. Place the walnut shell particles treated in step B2 into a mixed solution of 0.5-1.5 wt‰ polyacrylamide and 0.1-0.2 mol / L ferric chloride, stir at room temperature for 1.5-3.5 hours, filter and dry in a vacuum drying oven to constant weight.

[0010] Furthermore, an electric valve is provided on the pipeline between the wastewater storage tank and the comprehensive regulating tank; a lifting pump is provided between the comprehensive regulating tank and the air flotation device, between the air flotation device and the intermediate water tank, and inside the intermediate water tank.

[0011] Furthermore, a buoy-type oil collector is arranged in the wastewater storage tank to collect the floating oil on the surface.

[0012] Furthermore, the water inlet of the comprehensive regulating tank is provided with a mechanical grille.

[0013] The mechanical screen mainly intercepts larger suspended solids and floating objects in industrial and domestic sewage, which is beneficial to protecting the water pump, preventing the water pump and subsequent piping system from being blocked, and reducing the workload of subsequent treatment devices.

[0014] Furthermore, the flotation device includes a contact chamber, an air flotation tank, a water pump, an air dissolving tank, an air dissolving releaser, an air dissolving pump, and a slag skimmer; The contact chamber is arranged at the bottom of the flotation tank, the water pump is sequentially connected to the dissolved air pump, the dissolved air tank and the dissolved air releaser through pipelines, and the dissolved air releaser is located in the contact chamber; the skimmer is located at the upper part of the flotation tank.

[0015] The sewage from the wastewater storage tank is added with chemicals in the comprehensive regulating tank and then enters the contact chamber; the water pressurized by the water pump is sent to the dissolved air tank by the dissolved air pump, mixed with compressed air in the dissolved air tank to form dissolved air water, and then the dissolved air water is transported to the contact chamber by the pipeline, and meets the treated water after the reaction with the added chemicals in the contact chamber through the dissolved air releaser. Due to the sudden decrease in pressure after the dissolved air releaser, the gas escapes from the water to form a large number of micro bubbles. The flocs generated by the coagulation reaction of the treated water after the addition of chemicals are adhered by the bubbles, resulting in the overall specific gravity of the impurity flocs being less than that of water, and relying on buoyancy to float to the water surface, thereby obtaining solid-liquid separation, and the scum formed on the liquid surface of the flotation tank is regularly scraped out by the skimmer to remove suspended matter and organic matter in the water, thereby achieving the purpose of water purification.

[0016] Furthermore, the packing filter is a vertical cylindrical structure.

[0017] Furthermore, the drying temperature in the vacuum drying oven is 30-45°C.

[0018] The beneficial effects of the present invention are: The present invention modifies activated carbon and walnut shells and then mixes them as fillers of a filler filter. The modified activated carbon and the modified walnut shells complement each other and remove pollutants such as COD, ammonia nitrogen, phosphorus, and petroleum in oily sewage to the maximum extent, so as to improve the quality of tail water and enable the tail water to be more widely used. The modified activated carbon has high mechanical strength and is not easy to wear, and can effectively adsorb organic matter in sewage for a long time. It still has a good effect after intermittent operation for a total of 1000 hours, and has a long service life.

[0019] The present invention adopts an intermittent full-physical treatment system, which reduces the operation load and cost, has low operation and maintenance costs, saves energy and reduces consumption, reduces the use of chemical reagents to a minimum, and has a good treatment effect. DETAILED DESCRIPTION

[0020] The principles and features of the present invention are described below in conjunction with embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0021] Embodiment 1: An intermittent sewage treatment system for an oil terminal comprises a wastewater storage tank, a comprehensive regulating tank, an air flotation device, an intermediate water tank, a filler filter and a middle water tank which are sequentially connected by pipelines; An electric valve is provided on the pipeline between the wastewater storage tank and the comprehensive regulating tank; a lifting pump 1 is provided between the comprehensive regulating tank and the air flotation tank; a lifting pump 2 is provided between the air flotation device and the intermediate water tank; a lifting pump 3 is provided in the intermediate water tank; Among them, a float-type oil collector is installed in the wastewater storage tank; a mechanical grille is provided at the water inlet of the comprehensive regulating tank; the flotation device includes a contact chamber, a flotation tank, a water pump, an air dissolving tank, an air dissolving pump, and a skimmer; the contact chamber is arranged at the bottom of the flotation tank, and the water pump is connected to the air dissolving pump, the air dissolving tank, and the contact chamber in sequence through a pipeline; the skimmer is located at the upper part of the flotation tank; the packing filter is a vertical cylindrical structure. The packing of the packing filter is a mixture of modified activated carbon and modified walnut shells, and the mass ratio of the modified activated carbon to the modified walnut shell is 1.5:1; The preparation method of the modified activated carbon comprises the following steps: A1. Under nitrogen protection, calcine the 100-mesh activated carbon particles at 350°C for 3 hours; A2. Place the calcined activated carbon particles in acetic acid, stir at 45°C for 3 hours, filter, and dry in a vacuum drying oven at 35°C to constant weight; A3, placing the activated carbon particles treated in step A2 into a polyaluminium sulfate solution with a concentration of 8 wt%, stirring at 45°C for 3 hours, filtering, and drying in a vacuum drying oven at 35°C to constant weight; A4, placing the activated carbon particles treated in step A3 into a 0.1 mol / L potassium hydrogen phthalate solution, ultrasonically treating at 45°C for 2.5 hours, filtering, and drying in a vacuum drying oven at 35°C to constant weight; The preparation method of the modified walnut shell comprises the following steps: B1. Add walnut shell particles crushed to 100 mesh into boiling deionized water and heat to boil for 50-70 minutes; then calcine the walnut shell particles at 350° C. for 3 hours under nitrogen protection; B2, placing the calcined walnut shell particles into a 10wt% sodium hypochlorite solution, ultrasonically treating at 45°C for 2.5 hours, filtering, and drying in a vacuum drying oven at 35°C to constant weight; B3. The walnut shell particles treated in step B2 are placed in a mixed solution of 1 wt‰ polyacrylamide and 0.2 mol / L ferric chloride, mixed and stirred at room temperature for 2 hours, filtered, and dried in a vacuum drying oven at 35° C. to constant weight.

[0022] The above-mentioned intermittent wastewater treatment system for oil terminal is used to treat the oil terminal production wastewater, including the following steps: (1) Sewage enters the wastewater storage tank: The wastewater produced by the terminal enters the wastewater storage tank. A buoy-type oil collector is installed in the wastewater storage tank to collect floating oil on the surface of the wastewater storage tank.

[0023] (2) Comprehensive regulating tank treatment: sewage is discharged from the wastewater storage tank to the comprehensive regulating tank through the electric valve. The mechanical screen intercepts the larger suspended solids and floating objects in the sewage. The mechanical screen is cleaned 2-3 times a day to ensure smooth water inflow.

[0024] (3) Flotation treatment: After the chemicals are added to the sewage, it enters the contact chamber; the water pressurized by the water pump is sent to the dissolved air tank by the dissolved air pump, mixed with compressed air in the dissolved air tank to form dissolved air water, and then the dissolved air water is sent to the contact chamber by the pipeline, and meets the treated water after the reaction with the added chemicals in the contact chamber through the dissolved air releaser. Due to the sudden decrease in pressure after the dissolved air releaser, the gas escapes from the water to form a large number of micro bubbles. The flocs produced by the coagulation reaction of the treated water after the addition of chemicals are adhered by the bubbles, resulting in the overall specific gravity of the impurity flocs being less than that of water, and relying on buoyancy to float to the water surface, thereby achieving solid-liquid separation. The scum formed on the liquid surface is regularly scraped out by the skimmer to remove suspended matter and organic matter in the water, thereby achieving the purpose of water purification.

[0025] The air inlet flow of the air dissolving pump is about 10% of the water output and the water output is about 35% of the treated water. The outlet pressure is about 0.4MPa. The working pressure of the air dissolving tank is 3kg / cm 2 , designed reflux ratio 35%, total residence time 45min; dissolved air pump flow 25t / h, head 50m, power 7.5KW. When the dissolved air tank pressure > 0.30MPa, open the dissolved air tank outlet valve and adjust the reflux volume, generally 20% of the treated water volume. At the same time, start the drive device and observe the dissolved air water effect in the flotation tank. It is normal if the water distribution area is milky white and no large bubbles are generated.

[0026] (4) The effluent enters the intermediate water tank: The intermediate water tank plays the role of regulating the water volume in the process. Adjust the outlet valve of the lifting pump three to an outlet flow rate of about 10t / h. The lifting pump three of the intermediate water tank lifts the sewage into the packing filter.

[0027] (5) Packing filter treatment: Using the principle of filtration separation, the packing filter deeply adsorbs, reacts and filters pollutants such as COD, ammonia nitrogen and total phosphorus in oily wastewater.

[0028] The equipment specifications of the packing filter are: φ1600×4620; equipment type: vertical round container; equipment diameter: 1600mm; operating flow rate: 15m / h; water treatment volume: 30m³ / h; filter material height: 1600mm; design pressure: 0.6MPa; test pressure: 0.75MPa; working temperature: 4-50℃; mixer power: 2.2KW; water backwash intensity: 4-15L / (m 2 •s); Backwash expansion height: 1600mm.

[0029] (6) The effluent after being filtered by the packing filter enters the grey water tank, where the treated water is collected and reused as grey water.

[0030] Example 1 The indicators of oil terminal wastewater before and after treatment are shown in Table 1: Table 1 Various indicators of oil terminal production wastewater before and after treatment

[0031] Embodiment 2: The filler of the filler filter is a mixture of modified activated carbon and modified walnut shells, and the mass ratio of the modified activated carbon to the modified walnut shells is 1:1.5; the rest is the same as in Example 1 and will not be repeated here. Example 2 The various indicators of the oil terminal production wastewater after treatment are shown in Table 2: Table 2 Various indicators of wastewater produced by oil terminal after treatment

[0032] Comparative Example 1: The filler of the filler filter is a mixture of unmodified activated carbon and unmodified walnut shells, and the mass ratio of the unmodified activated carbon to the unmodified walnut shells is 1.5:1; the rest is the same as in Example 1 and will not be repeated here. Comparative Example 1 The various indicators of the oil terminal wastewater after treatment are shown in Table 3: Table 3 Various indicators of wastewater produced by oil terminal after treatment

[0033] Comparative Example 2: The filler of the filler filter is a mixture of unmodified activated carbon and unmodified walnut shells, and the mass ratio of the unmodified activated carbon to the unmodified walnut shells is 1:1.5; the rest is the same as in Example 1 and will not be repeated here. Comparative Example 2 The various indicators of the oil terminal wastewater after treatment are shown in Table 4: Table 4 Various indicators of wastewater produced by oil terminal after treatment

[0034] Comparative Example 3: The filler of the filler filter is modified walnut shell; the rest is the same as in Example 1 and will not be repeated here. Comparative Example 3 The various indicators of the oil terminal wastewater after treatment are shown in Table 5: Table 5 Various indicators of wastewater produced by oil terminal after treatment

[0035] Comparative Example 4: The filler of the filler filter is modified activated carbon; the rest is the same as in Example 1 and will not be repeated here. Comparative Example 4 The various indicators of the oil terminal wastewater after treatment are shown in Table 6: Table 6 Various indicators of wastewater produced by oil terminal after treatment

[0036] The removal rates of various test items of Examples 1-2 and Comparative Examples 1-4 are shown in Table 7: Table 7 Removal rate of each test item

[0037] It can be seen from the removal rates of various parameters in Example 1 and Example 2 that they are all above 95%, which shows that the mixed filler of modified activated carbon and modified walnut shell used in the present invention has an obvious treatment effect on oily wastewater. Compared with Example 2, Example 1 has a larger mass fraction of modified activated carbon added, and from the removal rates of various indicators, Example 1 has a better effect.

[0038] Comparative Example 1 treats the same wastewater as Example 1, but replaces the modified activated carbon and modified walnut shell mixed filter material with unmodified ordinary activated carbon and walnut shell mixed filter material; the removal rates of various parameters of Example 1 and Comparative Example 1 show that the suspended matter and chromaticity in Comparative Example 1 are acceptable, but the removal rates of other indicators are all lower than 58.7%. It can be seen that the present invention has a better treatment effect on sewage after modifying the filter material in the filter.

[0039] Comparative Example 2 treats the same wastewater as Example 2, but replaces the modified activated carbon and modified walnut shell mixed filter material with unmodified ordinary activated carbon and walnut shell mixed filter material; the removal rates of various parameters of Example 2 and Comparative Example 2 show that the suspended matter and chromaticity in Comparative Example 2 are acceptable, but the removal rates of other indicators are all lower than 57.9%. It can be seen that the present invention has a better treatment effect on sewage after modifying the filter material in the filter.

[0040] Comparative Example 3 treats the same wastewater as Examples 1 and 2, and Comparative Example 3 uses only modified walnut shells as the filter adsorption material of the filter; it can be seen from the removal rates of various parameters of Examples 1 and 2 and Comparative Example 3 that the removal rates of other pollutant indicators except the chromaticity index in Comparative Example 3 are all lower than 85.83%. It can be seen that the treatment effect of using only modified walnut shells as filter material for sewage is not as obvious as the effect of mixing modified activated carbon and modified walnut shells according to Examples 1 and 2.

[0041] Comparative Example 4 treats the same wastewater as that of Examples 1 and 2, and Comparative Example 4 uses only modified activated carbon as the filter adsorption material of the filter; it can be seen from the removal rates of various parameters of Examples 1 and 2 and Comparative Example 4 that the removal rates of other pollutant indicators except the chromaticity index in Comparative Example 4 are all lower than 85%. It can be seen that the treatment effect of using only modified activated carbon as the filter material for sewage is not as obvious as the effect of mixing modified activated carbon and modified walnut shell according to Examples 1 and 2.

[0042] The detection method, basis and instruments used are shown in Table 8: Table 8 Detection methods, basis and instruments used

[0043] The present invention modifies activated carbon and walnut shells and then mixes them as fillers for filler filters. The modified activated carbon and the modified walnut shells complement each other and remove pollutants such as COD, ammonia nitrogen, phosphorus, and petroleum in oily sewage to the maximum extent, so as to improve the quality of tail water and enable tail water to be more widely used. The addition of modified walnut shells solves the shortcomings of modified activated carbon filter materials, such as poor mechanical strength, easy wear and structural damage, and can effectively adsorb organic matter in sewage for a long time. The two modified filter materials are mixed and still have good effects after intermittent operation for a total of 1000 hours, and the service life is long. The present invention adopts an intermittent full physical treatment system, which reduces the operating load and cost, has low operating and maintenance costs, saves energy and reduces consumption, reduces the use of chemical reagents to a minimum, and has a good treatment effect.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An intermittent sewage treatment system for an oil terminal, characterized in that: It includes a wastewater storage tank, a comprehensive regulating tank, an air flotation device, an intermediate water tank, a filler filter and a middle water tank which are sequentially connected by pipelines; The filler of the filler filter is a mixture of modified activated carbon and modified walnut shell, and the mass ratio of the modified activated carbon to the modified walnut shell is (0.5-2):1; The modified activated carbon is obtained by treating activated carbon particles with calcination, acetic acid, polyaluminum sulfate and potassium hydrogen phthalate; the modified walnut shell is obtained by treating walnut shell fragments with ion water boiling, calcination, sodium hypochlorite and a mixed solution of polyacrylamide and ferric chloride.

2. The intermittent sewage treatment system for oil terminal according to claim 1 is characterized in that: The preparation method of the modified activated carbon comprises the following steps: A1. Under nitrogen protection, calcine the activated carbon particles of 100-150 mesh at 300-400℃ for 2-4 hours; A2. Place the calcined activated carbon particles in acetic acid, stir at 40-50°C for 2.5-3.5 hours, filter, and dry in a vacuum drying oven to constant weight; A3, placing the activated carbon particles treated in step A2 into a 6-10wt% polyaluminium sulfate solution, stirring at 40-50°C for 2.5-3.5 hours, filtering, and drying in a vacuum drying oven to constant weight; A4. Place the activated carbon particles treated in step A3 into a 0.1 mol / L potassium hydrogen phthalate solution, ultrasonically treat for 2-3 hours at 40-50°C, filter, and dry in a vacuum drying oven to constant weight.

3. The intermittent sewage treatment system for oil terminal according to claim 1 is characterized in that: The preparation method of the modified walnut shell comprises the following steps: B1. Add walnut shell particles crushed to 100-150 mesh into boiling deionized water and heat to boil for 50-70 minutes; then calcine the walnut shell particles at 300-400° C. for 2-4 hours under nitrogen protection; B2. Place the calcined walnut shell particles into a sodium hypochlorite solution with a concentration of 8-12 wt%, ultrasonically treat at 40-50° C. for 2-3 hours, filter, and dry in a vacuum drying oven to constant weight; B3. Place the walnut shell particles treated in step B2 into a mixed solution of 0.5-1.5 wt‰ polyacrylamide and 0.1-0.2 mol / L ferric chloride, stir at room temperature for 1.5-3.5 hours, filter and dry in a vacuum drying oven to constant weight.

4. The intermittent sewage treatment system for oil terminal according to claim 2 is characterized in that: An electric valve is provided on the pipeline between the wastewater storage tank and the comprehensive regulating tank; a lifting pump is provided between the comprehensive regulating tank and the air flotation device, between the air flotation device and the intermediate water tank, and inside the intermediate water tank.

5. The intermittent sewage treatment system for oil terminal according to claim 4 is characterized in that: A buoy-type oil collector is arranged in the wastewater storage tank.

6. The intermittent sewage treatment system for oil terminal according to claim 1 is characterized in that: The water inlet of the comprehensive regulating tank is provided with a mechanical grille.

7. The intermittent sewage treatment system for oil terminal according to claim 1 is characterized in that: The air flotation device comprises a contact chamber, an air flotation tank, a water pump, an air dissolving tank, an air dissolving releaser, an air dissolving pump, and a slag skimmer; The contact chamber is arranged at the bottom of the flotation tank, the water pump is sequentially connected to the dissolved air pump, the dissolved air tank and the dissolved air releaser through pipelines, and the dissolved air releaser is located in the contact chamber; the skimmer is located at the upper part of the flotation tank.

8. The intermittent sewage treatment system for oil terminal according to claim 1 is characterized in that: The packing filter is a vertical cylindrical structure.

9. The intermittent sewage treatment system for oil terminals according to claim 2 or 3, characterized in that: The drying temperature in the vacuum drying oven is 30-45°C.

Images