SE433489B - DEVICE FOR CURRENT WASTE WASTE FLUID IN A SEDIMENTATION POOL Separate from the liquid's surface liquid contaminants - Google Patents

Description

79 ~ Û5871t7 '2 15 20 25 30 40 starting point from the presence of the pollutant in solid or liquid form, A number of processes and equipment for separating substances according to their condition, specific gravity and grain size are known. Individual or combined precipitation, centrifugation and filtration are usually energy-intensive, which is why it is necessary to use separation devices which require the lowest possible efficiency, which have the greatest possible permeability and which require the least possible investment costs and operating costs.

A disadvantage of known separation devices - especially if the treated liquid contains contaminants of both higher and lower specific gravity as is usually the case with industrial wastewater liquids that simultaneously contain sand and oil contaminants - is that the equipment used must meet conflicting requirements.

In commonly used devices with sedimentation basins and separation basins, the effluent must flow laminarly at low velocity to deposit sand grains on the bottom of the subsoil and allow oil droplets to float to the surface, while on the other hand the effluent must flow at a sufficient rate for efficient separation from the surface of the liquid by means of a wiping device supported in the basin floating.

These conflicting requirements obviously cannot be met at the same time, so only a compromise is possible.

An additional practical difficulty lies in the fact that the amount of wastewater supplied can be subjected to rapid variations. However, these rapid variations disturb the flow pattern and cause wave phenomena both at the surface and at the depth, whereby already deposited grain material is stirred and the liquid level in the basin varies so that the separating means sometimes hangs freely in the air and is sometimes immersed in the liquid without performing any separation. . A wave front sweeping past the separating means can further fill the outlet channel with water and impair or even make all separation impossible.

In order to solve the said problem, it has been proposed according to Hungarian patent specification l69 472 to have the wiping means (separating means) supported on floats and provided with at least one row of nozzles, while the edge of the wiping knife used is set at or below the boundary layer between the waste liquid and the contaminant layer surface. The only disadvantage of this solution is related to the "purity" of the separated contaminants, as these always contain a small amount of the purified sewage liquid.The edge of the wiping knife can in practice not be set exactly at said boundary layer and dips always slightly down in the sewage, so the separated oil is always loaded with some water.

Devices are further known for collecting oil on the sea surface. These devices are usually designed in the form of a vessel towed on the sea surface. SE patent specification 227 562 shows such a collecting device for waste oil on a water surface. The device consists of a floating barge towed on the water, where the waste oil layer is shoveled via shovels via a width drain to an inner compartment of the vessel. Due to the movement of the vessel on the water and the movement of the blades, turbulence occurs across the width drain, whereby oil and water mix. The waste oil layer in the collection space is further exposed to a certain wave formation during towing. As a result, even in this case, the separated oil will be loaded with water.

The object of the invention is to provide a solution, whereby unmixed contaminant containing only traces of the waste liquid can be obtained.

This object is achieved according to the invention in a device of the kind initially stated in which the walls of the separation container extend upwards over the free level of surface layers of contaminants accumulated in the container and downwards in the liquid. The rear edge of the wiper blade is tightly connected to an upper edge of the separation container. The second width drain is formed by a width drain pipe attached to the separation container whose upwardly facing mouth is above the liquid level but below the free level of the layer of contaminants accumulated in the separation container, this width drain pipe being flexibly connected to an outlet on the sedimentation basin. can directly drain via the outlet line thus formed. The invention is described below in the form of exemplary embodiments and with reference to the accompanying drawing, which shows a schematic longitudinal section through the wiping device according to the invention. 5, Viewed in the direction of flow, the separating device is located downstream in an elongate basin or container 1, its wiping knife 5 being supported on floats 2. At least one row of nozzles 4 is mounted in front of the knife 5 and directed towards this knife. The rear edge of the knife 5 is tightly connected to a front upper wall edge (viewed in the direction of flow) of a separation container 5 open at the top, which is also open at the bottom. The separating container 5 may in the horizontal plane have, for example, a rectangular shape, its short sides being attached to the floats 2. The upper wall edge of the container 5 reaches above the liquid level while the lower edge of the wall extends to a certain depth down into the drain liquid.

As shown, the container 5 is completely open at the bottom, but can also be provided with a bottom wall in which at least one opening is accommodated. It is only essential that the container 5 is in communication with the contents of the container or basin 1.

Inside the container 5 is at least one outlet pipe 6 which in the case shown is flexibly connected to an outlet connection 8 for lighter contaminants, via a pleated metal pipe 7. An adjusting ring 9 is screwed onto the pipe 6 around its opening. However, the adjusting ring 9 can also be connected to the opening of the pipe in another way.

Further elements of the device not shown in the drawing, such as for example the inlet to the container 1, the outlet spout for heavier deposits, etc. can be made as shown in the Hungarian patent specification 169 472. It also shows how the device can be connected to the treatment plant for a sewer system.

The described device operates in the following manner. The oil-contaminated wastewater is introduced into the base bed 1 during laminar flow, whereby the oil rises to the surface and any heavier contaminants are deposited.

The layer 11 of contaminant floats on the surface 10 of the waste liquid and is driven under forced flow towards the wiping knife 40 by means of gas, especially air, from the nozzles 4. The wiping knife 5 extends below the surface 10. The direction of flow of the waste liquid is indicated by the arrow 12 and the flow direction the arrangement of the layer Mll_with the arrow l5¿ ___ * m “_ ~ - ~ l ~ mn 10 15 20 25 5 7903871-7 In order to work in the best way, the device must be set so that the wiping knife 3 extends immediately below the surface 10 of the liquid to be purified, while the opening of the outlet pipe 6 and the upper side of the adjusting ring 9, respectively, should be above the surface 10 but below the surface 14 of the separated contaminant in the container 5.

It is essential for the invention and its particular advantage that the waste liquid entrained with the contaminant layer during the pre-flow of the layer to the container 5 is separated from the contaminant layer. As a result, completely unmixed contaminant is obtained, which at most contains traces of cleaning liquid in the outlet.

The accuracy of the separation and the wiping can be regulated and controlled by adjusting the wiping knife 5 and the adjusting ring 9 in two steps, respectively.

As an example of the effect of the described device, the following can be stated: In a container of 2.2 X 4.0 m area and containing 5.28, stagnant water of type TH 5/22 may be added. By means of a device according to the invention, 28.5 l of fuel oil could be separated, while about 0.2 l of fuel oil remained in the separation vessel 5 on the surface of the water.

The separated fuel oil was burned in an oil burner of the type used, for example, for boilers. No disturbances, which could be attributed to the presence of water, occurred.

Claims (2)

7903871-7 (10 15 20 k) (_11 30 Patent claim Device for separating contaminants, especially oil contaminants, from flowing effluent in a sedimentation basin in a sedimentation basin, comprising a separating container supported at the bottom and at the top by floating openings with substantially vertical walls, slope towards the surface of the liquid and has a leading edge below and a trailing edge over the surface of the liquid to form there a first overflow drain to the separation container, nozzles located at the wiping knife arranged to direct an air flow towards the surface layer of contaminants fl ü: to drive this surface layer over the first overflow drain, and a second overflow drain located in the separation container, characterized in that the walls of the separation container (5) extend upwards over the free level (14) of surface layer (11) of contaminants accumulated in the container and downwards in the liquid, that the rear edge of the wiper blade (3) is tightly connected to an upper edge of the separation container (5), that the second overflow drain is formed by an overflow drain pipe (6) attached to the separation container, the upwardly directed mouth of which lies above the liquid level but below the free level (14) of the layer accumulated in the separation container (5). (11) of contaminants, this overflow drain pipe (6) being flexibly connected to an outlet (8) on the sedimentation basin (1) so that the layer (11) can drain directly via the outlet pipe thus formed. Device according to claim 1, characterized in that a vertically adjustable ring (9) is connected around the mouth of the overflow pipe (6), the upper edge of the ring (9) forming the second overflow.