RU2374181C2 - Device for cleaning of storm waters from oil products and suspended matters - Google Patents

Abstract

FIELD: technological processes, filters.

SUBSTANCE: invention is related to device for cleaning of storm waters from oil products and suspended matters and may be used for cleaning of rain storm water sewage. Device comprises zone of setting, thin-layer settling tank, filter with floating bed, sorption filter with activated coal. Setting zone is equipped with container for oil product removal, flow distributor. In lower part of semi-submerged plate there is a coalescent filter from corrugated cells made from oleophilic material. Zone of coalescence is separated from thin-layer setting tank by additional inclined semi-submerged plate. In zone of coalescence tray is installed for collection of oil product film, which is removed from tray to zone of setting by means of pump. Downstream thin-layer unit there are double-level cylindrical mechanical filters with large working surface from oleophilic sorption material, (for instance, sipron, megasorb, etc). Drain of cleaned water from sorption filter with activated coal is done from upper part.

EFFECT: improved extent of drain water cleaning from oil products and suspended matters.

3 cl, 2 dwg

Description

The device relates to techniques for treating water from petroleum products and suspended solids and can be used to treat rain storm sewage.

A well-known installation of the NPP "Polychim" in St. Petersburg, made in three series-connected concrete wells with an inner diameter of 1500 mm. In the first well there is a mechanical cleaning filter made in the form of a cartridge filled with lavsan. In the second well there is a sorption filter cartridge filled with activated carbon. The third well is a control - for visual inspection and water sampling for analysis. A water level regulator pipe is installed in it.

The main disadvantage of this device is as follows.

Stormwater by gravity immediately enters the lower part of the well with a mechanical filter cartridge and, passing through it from the bottom up, enters the upper part of the sorption cartridge of the second well. This technical solution (the absence of zones of sedimentation and removal of sediment) leads to the fact that the working section of the mechanical cartridge is quickly clogged with dirt and coalesced oil. Drops of oil will be captured by the rising flow of water, pass through the filter and accumulate in the upper part of the first well. Further, the film of oil will flow freely into the second well and clog the pores of activated carbon. This will lead to a quick failure of the coal cartridge and, consequently, a decrease in the degree of purification.

The closest in technical essence to the claimed device is the installation of treatment of oily wastewater "Svir-U" manufactured by ZAO TD "Engineering equipment", Moscow (see attached passport). The installation consists of a pump station for supplying wastewater to the treatment unit and the treatment unit itself. The cleaning unit consists of a sand trap hopper, a semi-submersible plate that separates the zone into which water enters after the sand trap hopper (zone I), and the settling zone (zone II). A swivel pipe is located in the settling zone, which serves to remove a film of oil products from the surface of the water and is connected by a flexible pipe to a tank for collecting oil products. Then the water enters the thin-layer block, where there is a further decrease in the concentration of suspended solids and petroleum products. Then the water through the overflow shutter enters the filter with a floating charge (polystyrene foam granules) and then into a separate metal container for finishing cleaning - sorption on activated carbon.

The disadvantages of this device are as follows.

1. In the first zone on the surface of the water will accumulate the oil in the form of a film, and with a significant content of the oil in the source wastewater (more than 20 mg / DM ³ ) - in the form of a layer. This device does not contain a node for removing oil from the first zone.

2. Since water flows unevenly into the first zone, regions with different vertical flow velocity appear. In a region with greater speed, the oil product does not have time to separate from the water and enters the next zone, passing under a semi-submerged partition.

3. Collecting a film of oil product with the help of a rotary pipe is a low-efficient and labor-intensive process. As a rule, the film has a small thickness (less than 1 · 10 ^-1 mm). Therefore, mainly the water layer is removed (in practice, at least 95%).

4. A film of oil accumulates in an area having a large surface area. It is known that the maximum concentration of petroleum products is contained in the effluents initially supplied for treatment. Further, the concentration of petroleum products in the incoming effluent decreases. Therefore, in the film collection zone under dynamic equilibrium, the reverse process partially occurs - water is saturated with oil from the film.

5. In this device, to reduce the concentration of suspended solids, a thin-layer sump and a filter with a floating charge (polystyrene foam granules) are used. The effectiveness of these stages is insufficient (wastewater is a colloidal solution) and water enters the charcoal filter with a high content of suspended solids. Because of this, there is a rapid colmatation of activated carbon granules, a sharp decrease in sorption capacity and cleaning efficiency (depth).

6. It is known that, for optimal sorption, activated carbon should always be in water. In the prototype method, the discharge from the charcoal filter occurs from the bottom of the container. This leads to periodic drying of activated carbon and, consequently, to a decrease in its sorption efficiency.

7. This device is not provided with a bypass line and if the wire filter is clogged on the drain pipe, the accumulated oil product will spill from zone 1 and the settling zone over the entire surface of the installation and beyond, with contamination of the surrounding area (this often happens in practice).

The technical result of the invention is to increase the degree of wastewater treatment from petroleum products and suspended solids.

The technical result provided by the invention is achieved by the fact that the claimed device is equipped with a container for oil product removal, a flow distributor, a coalescent filter made of corrugated cells made of oleophilic material is installed in the lower part of the semi-submersible plate, the coalescence zone is separated from the thin-layer settler by an additional inclined semi-submersible plate, in a coalescence zone has a tray for collecting a film of oil product, which is removed from the tray into the settling zone by the pump, after In the thin-layer sump, two-level cylindrical mechanical filters with a large working surface of oleophilic sorption material are installed; purified water is drained from the sorption filter with activated carbon from the upper part.

The container for collecting oil allows you to remove a layer of accumulated oil from the surface of the water, thereby reducing the chance of an undissolved oil product from breaking through from the settling zone to the coalescence zone. The flow distributor equalizes the vertical flow rate over the entire horizontal section, which contributes to a more efficient separation of oil products and suspended solids from water and an increase in the degree of purification. On a coalescence filter in corrugated cells made of oleophilic material, an effective separation of the dispersed phase — the oil product — from water occurs, which also increases the degree of purification.

The coalescence zone is separated from the thin-layer sump by an additional inclined semi-submersible plate so that the coalesced pop-up oil droplets after the coalescence filter will concentrate in this zone having a small surface area, which significantly reduces the likelihood of oil re-dissolving in water. In this zone, a tray for collecting a film of oil product is installed, which is removed into the zone of sedimentation by the pump. Thus, the concentration of oil occurs in only one zone.

After a thin-layer sump, two-level cylindrical mechanical filters with a large working surface of oleophilic sorption material, for example, sipron, megasorb, etc., are installed. This filter further purifies water from dissolved oil products and suspended solids due to the processes of mechanical filtration, coalescence and adsorption.

In the inventive device, the discharge from the coal container occurs from the top. Thus, activated carbon is in optimal conditions for adsorption, which also increases the degree of purification.

Figure 1 shows a schematic diagram of a device, figure 2 presents a top view.

The device consists of a pipeline 1 for supplying the initial storm water to the device, sand traps 2 for separating coarse suspended solids, a flow distributor 3 for equalizing the vertical flow rate of the treated water, a semi-submersible baffle 4, a coalescent filter 5, three silos for collecting sludge 6, an inclined semi-submersible baffle 7, a tray for collecting a film of oil product 8, a thin-layer sump 9. Drain from the upper level of the cylindrical mechanical filter 10 is carried out through the pipe 11, from the bottom - by tr to the suction line 17 to the filter with a floating charge 12. Next, the purified water through a perforated pipe 13 enters the sorption filter with activated carbon 14. The oil product is collected in a container 15, from where it is discharged from the device to the storage tank as it accumulates through the pipe 16. Figure 1 shows the lower water level in the device - 18 and the upper water level - 19. The film of oil from the tray 8 is removed by the pump 20. The purified water is drained from the device through pipeline 21. In figure 2, the bypass line 22 is indicated.

The inventive device operates as follows. Storm water through pipeline 1 enters, passing a sand trap 2, into the settling zone. Further, the water flow moves down under the semi-submersible plate 4. When passing through the flow distributor 3, the vertical speed is equalized. This contributes to a more efficient separation of the oil product from the water in the settling zone. When passing under a semi-submersible plate, heavy suspended solids are separated from the water stream and accumulated in the hopper 6. Then the water stream passes through the coalescence filter 5. On the cells of this filter, the dispersed phase - oil product is separated by droplets enlargement. These droplets, due to their lower density, float under the semi-submersible inclined partition 7 and accumulate in the form of a film in the tray 8. The water stream passes through a thin-layer settler 9, where there is a further separation of suspended solids, which, as they accumulate on the plates, slide down and accumulate in the hopper 6. Next water passes through two-level cylindrical mechanical filters 10 with a large working surface of oleophilic sorption material. It effectively separates dissolved oil and suspended solids from water.

After passing through mechanical filters, water flows, as in the prototype method, to a filter with a floating charge 12 and then to the last stage of purification — sorption on activated carbon 14. To prevent expanded polystyrene granules from entering the sorption zone on activated carbon, a perforated pipe 13 with a size of holes smaller than the diameter of the granules of polystyrene foam. The discharge from the charcoal filter 21 occurs from its upper part.

At the end of storm water from the pumping station, the upper level of the cylindrical mechanical filters stops working. Lowering the water level in the inventive device from the upper level 19 to the lower level 18 is due to the operation of the second level of filters. By lowering the water level, a vacuum is created in the pump 20 and the collected film of oil products from the tray enters the settling zone. The next time storm water arrives, the level in the inventive device will rise to the upper row of mechanical filters and the water flow will begin to flow through both rows of filters, since the overflow pipe from the bottom row 17 is at the level of the drain pipe of the upper row 11. As the oil accumulates in the zone of settling it the level will increase due to lower density than that of water and it will enter the container for collection 15 and further, through line 16 it will be removed from the device to the storage tank. In the event of a possible clogging of a double-row mechanical filter, a floating filter or a carbon filter, the untreated water will flow through the bypass line 22 again to the pump tank. This will eliminate the likelihood of oil product spreading from the zone of sedimentation and contamination of the entire installation and the surrounding area.

Claims (3)

1. A device for cleaning storm water from oil products and suspended solids, including a settling zone, a thin layer sump, a filter with a floating charge, an activated carbon sorption filter, characterized in that the device is equipped with a container for removing oil product, a flow distributor, in the lower part of the semi-submersible plate a coalescence filter of corrugated cells made of oleophilic material is installed, the coalescence zone is separated from the thin-layer sump by an additional inclined semi-submersible th plate, after thin-layer settler mounted cylindrical duplex filters with high mechanical working surface of the oleophilic sorption material, draining purified water sorption filter with activated carbon takes place from the top. 2. The device according to claim 1, characterized in that in the coalescence zone a tray for collecting a film of oil product is installed. 3. The device according to claim 2, characterized in that the film of oil is removed from the tray into the zone of sedimentation by the pump.

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