阅读说明：本技术 一种含油废水处理用两级重力分离装置及处理工艺 (Two-stage gravity separation device for treating oily wastewater and treatment process ) 是由 安杉 时锐 于海英 刘婷 于 2019-11-08 设计创作，主要内容包括：本发明公开了一种含油废水处理用两级重力分离装置,本发明公开了一种含油废水处理用两级重力分离装置,包括密闭的箱体,箱体的底板由从前至后方向依次连接的水平底板和第一斜板构成,箱体的内部设置有第二斜板,第二斜板沿从前至后的方向高度向上倾斜,第二斜板将箱体的内部空间分隔为互不连通的一级处理腔体和二级处理腔体,一级处理腔体内设置有第一波纹板组和第一隔油通水组件,二级处理腔体内设置有第二波纹板组和第二隔油通水组件。还公开了采用该装置的处理工艺。本发明的有益效果是：停留时间短、设备占地面积小、对原水波动的适应性较强；设备实现密闭化,且设备主体无运动部件,结构简单、运行效果稳定,设备成本低。(The invention discloses a two-stage gravity separation device for treating oily wastewater, which comprises a closed box body, wherein a bottom plate of the box body consists of a horizontal bottom plate and a first inclined plate which are sequentially connected from front to back, a second inclined plate is arranged in the box body, the second inclined plate is inclined upwards along the direction from front to back, the second inclined plate divides the inner space of the box body into a primary treatment cavity and a secondary treatment cavity which are not communicated with each other, a first corrugated plate group and a first oil-separating water-passing component are arranged in the primary treatment cavity, and a second corrugated plate group and a second oil-separating water-passing component are arranged in the secondary treatment cavity. Also discloses a treatment process adopting the device. The invention has the beneficial effects that: the retention time is short, the occupied area of the equipment is small, and the adaptability to raw water fluctuation is strong; the equipment realizes the sealing, the main body of the equipment has no moving parts, the structure is simple, the operation effect is stable, and the equipment cost is low.)

1. The utility model provides a two-stage gravity separation device for oily waste water treatment which characterized in that: comprises a closed box body, the box body is enclosed by a bottom plate, a front side wall, a top plate, a rear side wall, a left side wall and a right side wall, the bottom plate of the box body is composed of a horizontal bottom plate and a first inclined plate which are sequentially connected from the front to the rear direction, the first inclined plate inclines upwards from the front to the rear direction, a second inclined plate is arranged in the box body, the second inclined plate highly inclines upwards from the front to the rear direction, the second inclined plate divides the inner space of the box body into a primary treatment cavity and a secondary treatment cavity which are not communicated with each other, the primary treatment cavity is positioned at the upper part of the secondary treatment cavity,

the bottom of the front side wall of the box body is provided with a wastewater inlet communicated with the primary treatment cavity, a first corrugated plate group is arranged in the primary treatment cavity, the primary treatment cavity is divided into a first front side cavity and a first rear side cavity by the first corrugated plate group, the first corrugated plate comprises a plurality of first corrugated plates, the first front side cavity is communicated with the first rear side cavity through a channel formed between adjacent first corrugated plates, the top of the front side wall of the box body is provided with a primary oil outlet, the top of the inner wall of the front side wall of the box body is provided with a primary oil outlet weir plate matched with the primary oil outlet, a first baffle plate and a primary water outlet weir plate are sequentially arranged in the first rear side cavity along the front-to-rear direction, a channel for wastewater to pass is formed between the first baffle plate and the primary water outlet weir plate and between the primary water outlet weir plate and the top plate, and a first oil separation and water passing assembly is arranged between the lower ends of the first baffle plate and, the top heights of the first-stage oil outlet weir plate and the first-stage water outlet weir plate are the same;

a second corrugated plate group is arranged in the secondary treatment cavity, the second corrugated plate group divides the secondary treatment cavity into a second front side cavity and a second rear side cavity, the second corrugated plate comprises a plurality of second corrugated plates, the second front side cavity and the second rear side cavity are communicated through a channel formed between adjacent second corrugated plates, a primary water outlet communicated with the second rear side cavity is arranged at the position of the second inclined plate, which is positioned at the rear side of the primary water outlet weir plate,

the position department that first swash plate is located one-level delivery port rear side is provided with second grade oil export weir plate, the position department that first swash plate is located second grade oil export weir plate rear side is provided with the second grade oil export, second front side intracavity portion has set gradually second baffle and purified water export weir plate along the direction from the front to the back, form the passageway that supplies waste water to pass through between second baffle and the purified water export weir plate, be provided with second oil removal water passing component between the lower extreme of second baffle and the lower extreme of purified water export weir plate, the position department that the horizontal bottom plate is located second oil removal water passing component front side has seted up the purified water export.

2. The two-stage gravity separation device for treating oil-containing wastewater according to claim 1, characterized in that: the first purification component and the second purification component are both arranged along the direction from the front to the back in a downward inclination mode.

3. The two-stage gravity separation device for treating oil-containing wastewater according to claim 2, characterized in that: the included angle between the first purification component and the horizontal plane is 30-60 degrees, and the included angle between the second purification component and the horizontal plane is 20-60 degrees.

4. The two-stage gravity separation device for treating oil-containing wastewater according to claim 1, characterized in that: a plurality of first buckled plate, one-level oil export weir plate, first baffle, one-level delivery port weir plate, first oil removal leads to water subassembly, second grade oil export weir plate, second buckled plate, second baffle, purification water export weir plate and second oil removal lead to equal perpendicular to left side wall or right side wall of water subassembly, just a plurality of first buckled plate, one-level oil export weir plate, first baffle, one-level delivery port weir plate, first oil removal lead to water subassembly, second grade oil export weir plate, second buckled plate, second baffle, purification water export weir plate and second oil removal lead to the edge that water subassembly respectively corresponds all with left side wall or right side wall connection.

5. The two-stage gravity separation device for treating oil-containing wastewater according to claim 1, characterized in that: a plurality of first buckled plate and a plurality of second buckled plate all set up along the direction tilt up of preceding backward.

6. The two-stage gravity separation device for treating oil-containing wastewater according to claim 5, characterized in that: the included angles of the horizontal planes of the first corrugated plates are all 50-70 degrees, and the included angles of the second corrugated plates and the horizontal planes are all 20-50 degrees.

7. The two-stage gravity separation device for treating oil-containing wastewater according to claim 4, characterized in that: the first baffle, one-level delivery port weir plate, second grade oil export weir plate, second buckled plate, second baffle and purified water export weir plate all set up along the vertical direction.

8. The two-stage gravity separation device for treating oil-containing wastewater according to claim 1, characterized in that: the bottom of the front side wall is provided with a primary sand discharge port communicated with the primary treatment cavity, and the position of the horizontal bottom plate, which is positioned at the rear side of the purified water outlet weir plate, is provided with a secondary sand discharge port.

9. A treatment process using the two-stage gravity separation apparatus for treating oily wastewater according to any one of claims 1 to 8, characterized in that: the method comprises the following steps:

s1, primary processing flow: oily wastewater enters equipment from an inlet and integrally enters a first corrugated plate group, and the cross-section of water passing formed between adjacent first corrugated plates in the first corrugated plate group is alternately expanded and contracted, so that the collision efficiency of oil drops with small particle sizes is improved, and the oil drops with large particle sizes are further coalesced to form oil drops with large particle sizes;

after the oil phase and the water phase pass through the corrugated plate, the liquid level gradually rises and finally overflows through the first oil separation and water passing assembly, the first oil separation and water passing assembly has the physical property of blocking the oil phase from passing through, the oil phase with lower density is positioned above the liquid level, the oil phase continuously floats upwards and then passes through the first oil outlet weir plate and is discharged from the first oil outlet, and the water phase passes through the first oil separation and water passing assembly and is discharged from the first water outlet;

s2, secondary processing flow: the effluent purified by the first-stage separation enters a second-stage treatment cavity from a first-stage water outlet, then passes through a second corrugated plate group, and the alternate expansion and contraction of the water passing section formed between adjacent second corrugated plates in the second corrugated plate group improve the collision efficiency of small-particle-size oil drops, so that large-particle-size oil drops are formed by coalescence, the oil phase floating up between the second corrugated plates and the oil phase floating up under the blockage of a second oil separation and water passing component are discharged through a second-stage oil outlet after passing through a second-stage oil outlet weir plate, and the water phase passes through the second oil separation and water passing component and is discharged from a purified water outlet.

10. The process of claim 9, wherein: step S1, if the solid impurities are more, discharging the sediment from the first-stage sand outlet; and the step S2 further comprises discharging the precipitate from the secondary sand discharge port if the solid impurities are more.

Technical Field

The invention relates to the technical field of wastewater treatment, in particular to a two-stage gravity separation device for treating oily wastewater and a treatment process.

Background

With the rapid development of social economy, various catering mechanisms are enlarged day by day, the quantity of the catering mechanisms is increased rapidly, the production amount of kitchen waste water is increased, most of the waste water contains oil stains, and an oil-water separator is usually used for treating the kitchen waste water. At present, the oil removal method in kitchen waste sewage is generally realized by adopting an oil separation tank, the main defects are large floor area, high labor intensity and poor decontamination effect, and the other method is an oil-water separation method adopting an oil-collecting filter element.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a two-stage gravity separation device for treating oily wastewater and a treatment process.

The purpose of the invention is realized by the following technical scheme: a two-stage gravity separation device for treating oily wastewater comprises a closed box body, wherein the box body is enclosed by a bottom plate, a front side wall, a top plate, a rear side wall, a left side wall and a right side wall, the bottom plate of the box body is composed of a horizontal bottom plate and a first inclined plate which are sequentially connected from front to rear, the first inclined plate inclines upwards from front to rear, a second inclined plate is arranged in the box body, the second inclined plate highly inclines upwards from front to rear, the second inclined plate divides the inner space of the box body into a primary treatment cavity and a secondary treatment cavity which are not communicated with each other, the primary treatment cavity is positioned at the upper part of the secondary treatment cavity,

the bottom of the front side wall of the box body is provided with a wastewater inlet communicated with a primary treatment cavity, a first corrugated plate group is arranged in the primary treatment cavity, the primary treatment cavity is divided into a first front side cavity and a first rear side cavity by the first corrugated plate group, the first corrugated plate comprises a plurality of first corrugated plates, the first corrugated plates are parallel or approximately parallel to each other, the first front side cavity and the first rear side cavity are communicated through a channel formed between the adjacent first corrugated plates, a primary oil outlet is formed in the top of the front side wall of the box body, a primary oil outlet weir plate matched with the primary oil outlet is arranged on the top of the inner wall of the front side wall of the box body, a first baffle plate and a primary water outlet weir plate are sequentially arranged in the first rear side cavity along the front-to-rear direction, the corresponding edge of the first baffle plate is respectively connected with the top plate, the left side wall and the right side wall of the box body, and the corresponding edge of the primary water outlet weir, The left side wall is connected with the right side wall, a channel for wastewater to pass through is formed between the first baffle and the first-stage water outlet weir plate and between the first-stage water outlet weir plate and the top plate, a first oil separation and water passing assembly is arranged between the first baffle and the lower end of the first-stage water outlet weir plate, and the heights of the top ends of the first-stage oil outlet weir plate and the first-stage water outlet weir plate are the same so as to keep the liquid levels consistent;

a second corrugated plate group is arranged in the secondary treatment cavity, the second corrugated plate group divides the secondary treatment cavity into a second front side cavity and a second rear side cavity, the second corrugated plate comprises a plurality of second corrugated plates which are parallel or approximately parallel, the second front side cavity is communicated with the second rear side cavity through a channel formed between the adjacent second corrugated plates, a primary water outlet communicated with the second rear side cavity is arranged at the position of the second inclined plate at the rear side of the primary water outlet weir plate,

the position department that first swash plate is located one-level delivery port rear side is provided with second grade oil export weir plate, the position department that first swash plate is located second grade oil export weir plate rear side is provided with second grade oil export, second front side intracavity portion has set gradually second baffle and purified water export weir plate along the direction from the front to the back, the corresponding edge of second baffle respectively with the second swash plate, left side wall and right side wall are connected, the corresponding edge of purified water export weir plate respectively with horizontal bottom plate, left side wall and right side wall are connected, form the passageway that supplies waste water to pass through between second baffle and the purified water export weir plate, be provided with second oil removal water passing component between the lower extreme of second baffle and the lower extreme of purified water export weir plate, the position department that horizontal bottom plate is located second oil removal water passing component front side has seted up the purified water export.

The corrugated plate is utilized to increase the separation efficiency of oil-water two phases in a gravity field and shorten the retention time of equipment; in addition, the oil-separating water-passing assembly further improves the phase distribution state of oil-water phases in the equipment while increasing the oil-water separation efficiency, so that the flow field in the equipment is more suitable for oil-water two-phase separation. Finally, through the two-stage oil-water separation process in one box body, the equipment is compact, efficient and closed.

Preferably, the first purification assembly and the second purification assembly are arranged in a manner of inclining downwards along the direction from front to back. Further preferably, the angle between the first purification assembly and the horizontal plane may be 30 ° to 60 ° to prevent the formation of dead zones, and preferably, the angle is 45 °. Similarly, the angle between the second purifying component and the horizontal plane can be 20-60 degrees, and preferably, the angle is 30 degrees.

Preferably, a plurality of first buckled plates, one-level oil outlet weir plate, first baffle, one-level delivery port weir plate, first oil removal water flowing component, second grade oil outlet weir plate, second buckled plate, second baffle, purified water outlet weir plate and second oil removal water flowing component all perpendicular to left side wall or right side wall and the edge that corresponds all be connected with left side wall or right side wall.

According to the Harvest shallow pool principle, the distance between the corrugated plates is small, and the particle size range of oil drops of an oil phase to be separated can be greatly improved, namely, the oil drops with small particle size and low floating speed in a common gravity field have good floating capacity after entering a shallow channel between the corrugated plates; in addition, the corrugated plate is internally provided with water passing sections which are alternately expanded and contracted, so that the collision efficiency of oil drops with small particle sizes is improved, and then the oil drops with large particle sizes are formed by coalescence, and the aim of increasing the separation efficiency is fulfilled. Because the bulge of oil meeting in the buckled plate assembles, consequently can promote the floating of assembling the oil phase through the horizontal contained angle of adjusting the buckled plate, so preferred, a plurality of first buckled plates and a plurality of second buckled plates all along the direction tilt up setting from the past to the back. Further preferably, the included angle of the horizontal plane of each of the plurality of first corrugated plates is 50 to 70 degrees, and preferably, the included angle is 60 degrees. Because the concentration of oil in the wastewater in the secondary separation area is greatly reduced, the horizontal included angle of the second corrugated plates is flatter to prevent the wastewater from falling too fast and bringing away too much oil phase which can not float upwards, so that the included angles between the plurality of second corrugated plates and the horizontal plane are all 20-50 degrees, and preferably, the included angle is 45 degrees.

Preferably, the first-stage oil outlet weir plate is composed of a horizontal plate and a vertical plate, the first-stage oil outlet weir plate and the front side wall, the left side wall and the right side wall form a groove body with an upper opening, and the first-stage oil outlet is communicated with the groove body.

Preferably, first baffle, one-level delivery port weir plate, second grade oil export weir plate, second buckled plate, second baffle and purified water export weir plate all set up along the vertical direction.

When the oily wastewater contains solid particles (such as silt, suspended matters and the like), preferably, the bottom of the front side wall is provided with a primary sand discharge port communicated with the primary treatment cavity, and the position of the horizontal bottom plate, which is positioned at the rear side of the purified water outlet weir plate, is provided with a secondary sand discharge port. Similarly, when the emulsification degree of the oily wastewater is higher, an aeration device can be added; when the viscosity of the oily wastewater is high, a back washing process can be added, namely, clear water is pumped into the oily wastewater from an outlet branch, and the oily wastewater is discharged from an inlet branch after running reversely.

Optionally, the first oil-separating and water-passing component and the second oil-separating and water-passing component are both components for preventing oil phase from passing through and allowing water phase to pass through, and may adopt super-amphiphobic or amphiphobic net membranes disclosed in chinese patent 201910126464.X, or may adopt other commercially available oil-blocking and water-passing products.

The treatment process adopting the two-stage gravity separation device for treating the oily wastewater comprises the following steps:

s1, primary processing flow: oily wastewater enters equipment from an inlet and integrally enters a first corrugated plate group, and the cross-section of water passing formed between adjacent first corrugated plates in the first corrugated plate group is alternately expanded and contracted, so that the collision efficiency of oil drops with small particle sizes is improved, and the oil drops with large particle sizes are further coalesced to form oil drops with large particle sizes;

after the oil phase and the water phase pass through the corrugated plate, the liquid level gradually rises and finally overflows through the first oil separation water passing assembly, and as the first oil separation water passing assembly has the physical property of blocking the oil phase from passing through and the oil phase with lower density is positioned above the liquid level, the oil phase continuously floats upwards and then passes through the first-stage oil outlet weir plate and is discharged from the first-stage oil outlet; the water phase is discharged from the first-stage water outlet through the first oil separation water passing assembly.

In the primary treatment cavity, the fluid flows in a counter-flow mode (from bottom to top), the oil-containing concentration of the oil-containing wastewater in the primary separation cavity is high, and the counter-flow mode is suitable for the oil phase to float upwards; meanwhile, if the solid impurities are more, the solid impurities are easy to precipitate and are discharged from the sand discharge port.

The oil phase flows over the first-stage oil outlet weir plate and then enters the oil collecting tank to be discharged, and due to the flow blocking and stabilizing effects of the first-stage oil outlet weir plate, the water content of the sewage oil discharged from the first-stage oil outlet is low, so that the sewage oil can be directly recycled or enters other equipment to further remove the water phase. And the water phase and a small part of the oil phase which is not separated pass through the first oil removal water passing assembly, cross over the first-stage water outlet weir plate, are discharged from the first-stage water outlet and enter the secondary treatment cavity.

The primary treatment process has a complete oil-containing wastewater separation effect, and the effect of adding the secondary separation is as follows: firstly, the separation effect is further improved, namely the oil-containing concentration of the final clear water is reduced to the maximum extent, and the scenes with high requirements on zero discharge of waste water, waste water recycling and the like are met; secondly, the residence time is reduced, and the volume of the equipment is reduced; thirdly, when the fluctuation of the water quantity, pollutant components and content of the raw water of the wastewater is large, the traditional single-stage treatment equipment is difficult to meet the requirements (for example, equipment such as a hydrocyclone is sensitive to parameters such as raw water flow, pressure and the like, an air floatation device is sensitive to raw water oil-containing concentration, medicament dosage and the like, a coalescence technology has high requirements on particle impurities, viscosity and the like of the oil-containing wastewater), and the multi-stage series/parallel complete treatment equipment has the defects of large investment and large occupied area.

S2, secondary processing flow: the effluent purified by the first-stage separation enters a second-stage treatment cavity from a first-stage water outlet, then passes through a second corrugated plate group, and the alternate expansion and contraction of the water passing section formed between adjacent second corrugated plates in the second corrugated plate group improve the collision efficiency of small-particle-size oil drops, so that large-particle-size oil drops are formed by coalescence, the oil phase floating up between the second corrugated plates and the oil phase floating up under the blockage of a second oil separation and water passing component are discharged through a second-stage oil outlet after passing through a second-stage oil outlet weir plate, and the water phase passes through the second oil separation and water passing component and is discharged from a purified water outlet. When the discharge amount of the secondary oil outlet is small, intermittent discharge operation can be adopted; when the water concentration of the secondary oil outlet is too high, part or all of the discharged liquid of the secondary oil outlet can be returned to the primary separation inlet.

The oil-water mixture entering the secondary treatment cavity has greatly reduced oil content, and the oil-water mixture flows in a concurrent flow mode to increase the length of the movement path of the oil phase in the secondary treatment cavity and achieve the purpose of increasing the coalescence degree of the oil phase. Specifically, part of the oil phase floats upwards or has a floating trend in the second corrugated plate, and the oil phase falling along with the whole oily wastewater floats upwards again under the combined action of the blocking of the second oil-separating and water-communicating component and the flow guiding of the purified water outlet weir plate. The floating oil phase falls into the oil collecting tank after overflowing the secondary oil outlet weir plate and is discharged, if particle impurities still exist, the oil phase can be discharged through the secondary sand discharge port (because the particle impurities do not necessarily exist in the oily wastewater, whether the sand discharge port is arranged or not is determined according to the characteristics of the raw water).

And the step S1 further comprises discharging the precipitate from the first-stage sand outlet if the solid impurities are more.

And the step S2 further comprises discharging the precipitate from the secondary sand discharge port if the solid impurities are more.

The invention has the following advantages:

the invention has short retention time, small occupied area of equipment and stronger adaptability to raw water fluctuation; the equipment realizes the sealing, the main body of the equipment has no moving part, the structure is simple, the operation effect is stable, and the equipment cost is reduced to the maximum extent under the condition of ensuring the high-efficiency oil-water separation efficiency.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

FIG. 2 is a schematic diagram of the flow path of the oil phase and the water phase according to the present invention.

Detailed Description

The invention is further described with reference to the accompanying drawings in which:

as shown in figure 1, a two-stage gravity separation device for treating oily wastewater comprises a closed box body, the box body is enclosed by a bottom plate, a front side wall 1, a top plate 2, a rear side wall 3, a left side wall 4 and a right side wall (not shown in the figure, figure 1 is a structural schematic diagram after the right side wall is removed), the bottom plate of the box body is composed of a horizontal bottom plate 5 and a first inclined plate 6 which are sequentially connected from the front to the rear direction, the first inclined plate 6 inclines upwards from the front to the rear, a second inclined plate 7 is arranged in the box body, the second inclined plate 7 highly inclines upwards along the direction from the front to the rear, the second inclined plate 7 separates the inner space of the box body into a primary treatment cavity 23 and a secondary treatment cavity 24 which are not communicated with each other, and the primary treatment cavity is positioned at the upper part of the secondary treatment cavity,

the bottom of the front side wall 1 of the box body is provided with a wastewater inlet 8 communicated with a primary treatment cavity 23, a first corrugated plate group 9 is arranged in the primary treatment cavity 23, the primary treatment cavity is divided into a first front side cavity 25 and a first rear side cavity 26 by the first corrugated plate group 9, the first corrugated plate comprises a plurality of first corrugated plates, the first corrugated plates are parallel or approximately parallel to each other, the first front side cavity 25 and the first rear side cavity 26 are communicated through a channel formed between the adjacent first corrugated plates, the top of the front side wall 1 of the box body is provided with a primary oil outlet 10, the top of the inner wall of the front side wall 1 of the box body is provided with a primary oil outlet weir plate 11 matched with the primary oil outlet 10, the first rear side cavity 26 is internally provided with a first baffle plate 12 and a primary water outlet plate 13 in sequence along the front-to-rear direction, the corresponding edge of the first baffle plate 12 is respectively connected with the top plate 2 of the box, The left side wall 4 is connected with the right side wall, the corresponding edge of the first-stage water outlet weir plate 13 is respectively connected with the second inclined plate 7, the left side wall 4 and the right side wall, a channel for wastewater to pass is formed between the first baffle plate 12 and the first-stage water outlet weir plate 13 and between the first-stage water outlet weir plate 13 and the top plate 2, a first oil separation and water passing assembly 14 is arranged between the first baffle plate 12 and the lower end of the first-stage water outlet weir plate 13, and the top ends of the first-stage oil outlet weir plate 11 and the first-stage water outlet weir plate are the same in height so as to keep the liquid levels consistent;

a second corrugated plate group 15 is arranged in the secondary treatment cavity 24, the second corrugated plate group 15 divides the secondary treatment cavity into a second front side cavity 27 and a second rear side cavity 28, the second corrugated plate comprises a plurality of second corrugated plates which are parallel or approximately parallel, the second front side cavity 27 and the second rear side cavity 28 are communicated through a channel formed between the adjacent second corrugated plates, a primary water outlet 16 communicated with the second rear side cavity 28 is arranged at the position of the second inclined plate 7 at the rear side of the primary water outlet weir plate 13,

the position department that first swash plate 6 is located the one-level delivery port 16 rear side is provided with second grade oil outlet weir plate, the position department that first swash plate 6 is located second grade oil outlet weir plate rear side is provided with second grade oil export 18, second front side cavity 27 is inside to have set gradually second baffle 19 and purified water export weir plate along the direction from the front to the back, the corresponding edge of second baffle 19 respectively with second swash plate 7, left side wall 4 and right side wall are connected, the corresponding edge of purified water export weir plate respectively with horizontal bottom plate 5, left side wall 4 and right side wall are connected, form the passageway that supplies waste water to pass through between second baffle 19 and the purified water export weir plate, be provided with second oil removal water passing assembly 21 between the lower extreme of second baffle 19 and the lower extreme of purified water export weir plate, purified water export 22 has been seted up to the position department that horizontal bottom plate 5 is located second oil removal water passing assembly 21 front side.

The corrugated plate is utilized to increase the separation efficiency of oil-water two phases in a gravity field and shorten the retention time of equipment; in addition, the oil-separating water-passing assembly further improves the phase distribution state of oil-water phases in the equipment while increasing the oil-water separation efficiency, so that the flow field in the equipment is more suitable for oil-water two-phase separation. Finally, through the two-stage oil-water separation process in one box body, the equipment is compact, efficient and closed.

Preferably, the first purification assembly and the second purification assembly are arranged in a manner of inclining downwards along the direction from front to back. Further preferably, the angle between the first purification assembly and the horizontal plane may be 30 ° to 60 ° to prevent the formation of dead zones, and preferably, the angle is 45 °. Similarly, the angle between the second purifying component and the horizontal plane can be 20-60 degrees, and preferably, the angle is 30 degrees.

Preferably, the plurality of first corrugated plates, the first-stage oil outlet weir plate 11, the first baffle plate 12, the first-stage water outlet weir plate 13, the first oil removal water passing assembly 14, the second-stage oil outlet weir plate, the second corrugated plate, the second baffle plate 19, the purified water outlet weir plate and the second oil removal water passing assembly 21 are all perpendicular to the left side wall 4 or the right side wall, and corresponding edges are all connected with the left side wall 4 or the right side wall.

According to the Harvest shallow pool principle, the distance between the corrugated plates is small, and the particle size range of oil drops of an oil phase to be separated can be greatly improved, namely, the oil drops with small particle size and low floating speed in a common gravity field have good floating capacity after entering a shallow channel between the corrugated plates; in addition, the corrugated plate is internally provided with water passing sections which are alternately expanded and contracted, so that the collision efficiency of oil drops with small particle sizes is improved, and then the oil drops with large particle sizes are formed by coalescence, and the aim of increasing the separation efficiency is fulfilled. Because the bulge of oil meeting in the buckled plate assembles, consequently can promote the floating of assembling the oil phase through the horizontal contained angle of adjusting the buckled plate, so preferred, a plurality of first buckled plates and a plurality of second buckled plates all along the direction tilt up setting from the past to the back. Further preferably, the included angle of the horizontal plane of each of the plurality of first corrugated plates is 50 to 70 degrees, and preferably, the included angle is 60 degrees. Because the concentration of oil in the wastewater in the secondary separation area is greatly reduced, the horizontal included angle of the second corrugated plates is flatter to prevent the wastewater from falling too fast and bringing away too much oil phase which can not float upwards, so that the included angles between the plurality of second corrugated plates and the horizontal plane are all 20-50 degrees, and preferably, the included angle is 45 degrees.

Preferably, the first-stage oil outlet weir plate 11 is composed of a horizontal plate and a vertical plate, the first-stage oil outlet weir plate 11, the front side wall 1, the left side wall 4 and the right side wall enclose a groove body with an upper opening, and the first-stage oil outlet 10 is communicated with the groove body.

Preferably, the first baffle 12, the first-stage water outlet weir plate 13, the second-stage oil outlet weir plate, the second corrugated plate, the second baffle 19 and the purified water outlet weir plate are all arranged along the vertical direction.

When the oily wastewater contains solid particles (such as silt, suspended matters and the like), preferably, the bottom of the front side wall 1 is provided with a primary sand discharge port 29 communicated with the primary treatment cavity, and the horizontal bottom plate 5 is provided with a secondary sand discharge port 30 at the position behind the purified water outlet weir plate. Similarly, when the emulsification degree of the oily wastewater is higher, an aeration device can be added; when the viscosity of the oily wastewater is high, a back washing process can be added, namely, clear water is pumped into the oily wastewater from an outlet branch, and the oily wastewater is discharged from an inlet branch after running reversely.

Optionally, the first oil-separating and water-passing component 14 and the second oil-separating and water-passing component 21 are both components for preventing oil phase from passing through and allowing water phase to pass through, and can adopt super-amphiphobic or amphiphobic net membranes disclosed in Chinese patent 201910126464.X, and can also adopt other commercially available oil-blocking and water-passing products.

Referring to fig. 2, the treatment process using the two-stage gravity separation apparatus for treating oily wastewater comprises the following steps:

s1, primary processing flow: oily wastewater enters equipment from an inlet and integrally enters a first corrugated plate group 9, and the cross-section of water passing formed between adjacent first corrugated plates in the first corrugated plate group 9 is alternately expanded and contracted, so that the collision efficiency of oil drops with small particle sizes is improved, and the oil drops with large particle sizes are further coalesced to form oil drops with large particle sizes;

after the oil phase and the water phase pass through the corrugated plate, the liquid level gradually rises and finally overflows through the first oil separation and water passing component 14, and as the first oil separation and water passing component 14 has the physical property of blocking the oil phase from passing through and the oil phase with lower density is positioned above the liquid level, the oil phase continuously floats upwards and then passes through the primary oil outlet weir plate 11 and is discharged from the primary oil outlet 10; the water phase passes through the first oil removal water passing assembly 14 and is discharged from the primary water outlet.

In the primary treatment cavity 23, the fluid flows in a counter-flow mode (from bottom to top), the oil-containing concentration of the oil-containing wastewater in the primary separation cavity is high, and the counter-flow mode is suitable for oil phase floating; meanwhile, if the solid impurities are more, the solid impurities are easy to precipitate and are discharged from the sand discharge port.

The oil phase flows over the first-stage oil outlet weir plate 11 and then enters the oil collecting tank to be discharged, and due to the flow blocking and stabilizing effects of the first-stage oil outlet weir plate 11, the water content of the sewage oil discharged from the first-stage oil outlet 10 is low, so that the sewage oil can be directly recycled or enters other equipment to further remove the water phase. The water phase and a small part of the oil phase which is not separated pass through the first oil removal and water passing assembly 14, cross the weir plate of the primary water outlet, are discharged from the primary water outlet and enter the secondary treatment cavity 24.

The primary treatment process has a complete oil-containing wastewater separation effect, and the effect of adding the secondary separation is as follows: firstly, the separation effect is further improved, namely the oil-containing concentration of the final clear water is reduced to the maximum extent, and the scenes with high requirements on zero discharge of waste water, waste water recycling and the like are met; secondly, the residence time is reduced, and the volume of the equipment is reduced; thirdly, when the fluctuation of the water quantity, pollutant components and content of the raw water of the wastewater is large, the traditional single-stage treatment equipment is difficult to meet the requirements (for example, equipment such as a hydrocyclone is sensitive to parameters such as raw water flow, pressure and the like, an air floatation device is sensitive to raw water oil-containing concentration, medicament dosage and the like, a coalescence technology has high requirements on particle impurities, viscosity and the like of the oil-containing wastewater), and the multi-stage series/parallel complete treatment equipment has the defects of large investment and large occupied area.

S2, secondary processing flow: the effluent purified by the first-stage separation enters the second-stage treatment cavity 24 from the first-stage water outlet 16, passes through the second corrugated plate group 15 immediately, and the collision efficiency of small-particle-size oil drops is improved by the alternate expansion and contraction of the water passing section formed between adjacent second corrugated plates in the second corrugated plate group 15, so that large-particle-size oil drops are formed by coalescence, oil phases floating up between the second corrugated plates and oil phases floating up under the blocking of the second oil separation and water passing component 21 are discharged from the second-stage oil outlet 18 after passing through the weir plate of the second-stage oil outlet, and water phases pass through the second oil separation and water passing component 21 and are discharged from the purified water outlet 22. When the discharge amount of the secondary oil outlet 18 is small, intermittent discharge operation can be adopted; when the water concentration of the secondary oil outlet 18 is too high, part or all of the effluent of the secondary oil outlet 18 can be returned to the primary separation inlet.

The oil-water mixture entering the secondary treatment chamber 24, the oil concentration of which is greatly reduced, is then operated in a forward flow manner to increase the length of the movement path of the oil phase in the secondary treatment chamber 24, so as to increase the degree of coalescence of the oil phase. Specifically, part of the oil phase floats upwards or has a floating tendency in the second corrugated plate, and the oil phase falling along with the whole oily wastewater floats upwards again under the combined action of the blocking of the second oil-separating and water-communicating component 21 and the flow guiding of the purified water outlet weir plate. The floating oil phase falls into the oil collecting tank after overflowing the secondary oil outlet weir plate and is discharged through the secondary sand discharge port 30 if particle impurities still exist (because the particle impurities do not necessarily exist in the oily wastewater, whether the sand discharge port is arranged or not is determined according to the characteristics of the raw water).

The step S1 further includes discharging the precipitate from the first-stage sand outlet 29 if the solid impurities are more.

The step S2 further includes discharging the precipitate from the secondary sand outlet 30 if the solid impurities are more.