SE453364B - PROCEDURE AND DEVICE FOR FILTERING WITH SPILLABLE FILTER CHECK FOR WATER PURIFICATION - Google Patents

Description

10 15 20 25 30 35 453 364 2 shall be filtered, the water flowing through the filter to the surrounding body of water, while the particles remain within the filter, in the filter bag, the particles collected in the bag are discharged to a and that then a certain amount of particles have accumulated the water supply is interrupted and those in the mass separate place.

The invention also relates to a method for carrying out the process. intended device, the design of which is stated in claim 7.

An application of special interest for application of the invention is the decontamination of eutrophied - eutrophied - lakes and streams. In these, amounts of algae, plankton, are formed and vegetation, which together contribute to increased turbidity, overgrowth and deteriorating oxygen conditions.

In countries with cold climates, algae and planks occur. tonnes seasonally. During the summer, flowering occurs periods of abundant biological growth due to overgrowth copious amounts of nutrients. After the end of the period, the death toll drops algae and plankton down to the bottom sediments. During winter half a year arises since oxygen-poor conditions in the bottom sediments, releasing the phosphorus and nitrogen of the cell material and will be available for cell construction for the next plant equality generation. In this way, an endless cycle course of nutrients in lakes, with accompanying successive Plant.

In general it can be said that it should still be missing cheap and efficient technology to be able to break this cycle and separate excess nutrients from the the water phase of the race and / or its bottom sediment phase. Tfots om- comprehensive and costly efforts with i.a. dredging, chemical manipulation of the bottom sediments, chemical precipitation, oxygenation, etc., the results have so far appeared as doubtful in relation to the scope of the efforts and costs.

This invention contributes new solutions to these problem. During the flowering period, the nutrients are bound in algae and plankton. They are therefore technically available for filtration provided that appropriate filter technology would be available. 10 15 20 25 30 35 453 364 3 With floating filter bags out in the lake - according to this invention - the problem should have been solved. The algal mass that is separated and concentrated inside the filter bags, pumped under the bags flushing phases to, for example, an onshore reception station for further processing.

The particular way of applying the invention therein context is set out in more detail in claims 6 and 8.

The invention is described in more detail in connection with the appended claims drawings.

Figure 1 is a schematic plan view showing the invention application to general filter technology. to Figure 1. a device Figure 2 is a vertical cross section Figure 3 is a schematic plan view of according to the invention used for remediation of a lake.

Figure a is a partial vertical section of some parts of the device in Figure 3, on a larger scale.

Figure 5 is a plan view showing a modification of the the scheme of Figure 3.

Figure 6 is a schematic plan view showing the invention applied to water purification in a fish farming basin.

Figures 1 and 2 show a delimited pool space 27 filled with filtered water, in which two submersible filter bags 10 are arranged in a manner which is shown in more detail in Figure 2. The sacks are tensioned over rings or frames 11, which are through struts 12 attach to suspension devices 13. The bags are suspended that they are partly above, partly below the water surface whereby the sack bottom is of course located so, 15 in the basin 27, in the body of water. The walls 14 of the bags 10 act as filter cloth of the type permeable membrane.

Water, Through intake lines 8 and 9, which may be pressure lines. to be filtered begins in the filter bags or self-contained lines.

At the passage of water through the walls 14 of the bags the water is filtered so that filterable material remains in the bag preferably on its inner walls, while the filtered water, 10 15 20 25 30 35 453 364 6 ~ clear phase, flows out through the walls 14 in the adjacent 'and surrounding pool or water area 27.

Alft because filterable substance is separated from the filter the inner walls of the bags, the flow resistance and water the level 16 inside the bag is raised in relation to the water area water level 15. When the level difference has reached a maximum If the value is switched on, the flushing is started, manually or automatically. by starting a purge pump 17 placed inside the bag.

The purge pump 17 pumps filtered substance from the filter bag 10 through a pressure line 18 and the main line 19 - which is together for the two filter bags - to a receiving station for further treatment of filtered off substance. In the reception the station can include devices for thickening, storage for later removal, biogas digestion and energy recovery, lime mixture for pulp use as manure 1 Agriculture, etc.

Simultaneously with the start of the purge pump 17, an in- blowing of compressed air, manually or automatically, in the filter the bags 10, whereby air supply takes place through a trunk line 21, branch lines 22 and air injection nozzles 23. The latter said are positioned so that the compressed air jet becomes tangential and horizontally directed, giving a helical and upward movement to the air bubbles so that filtered mass in the bag is brought into rotation; This causes to be filtered out particles are more easily released from the inner walls of the filter bag and ouges towards the center flush pump 17.

By overflowing into the pool space 27, departing through clean water line 31 and main line 30 a flow which is equal to the input flow in the intake lines 8 and 9.

The effects of air supply in connection with flushing can alternatively provided equivalent to vertical-axis, mechanical stirrers.

During the flushing phase, the water supply is stopped. This causes the water level 24 in the bag to drop below the water level 15 in adjacent water area 27 - this as a result of the flow the resistance in the walls when the purge pump is in operation. During flushing consequently, the direction of flow through the walls becomes it l! 10 15 20 25 30 35 453 364 5 opposite compared to the operating mode. This contributes effectively that filtered particles detach from the inner walls of the bag during flushing.

Water from the same is suitably used as rinsing water water area in which the filter bags float, i.e. former felt distilled water. This means that clean flushing water is close by hands in virtually unlimited quantities. Figures 3 and 4 show how the filtration technique according to the invention can be applied for decontamination of lakes, which as mentioned above is a significant application.

In Figures 3 and 4, the corresponding details are the same reference numerals as in Figures 1 and 2. A system of hanging cloths applied to a water area 1, for example of plastic, is suspended from floating pontoons 2.

At the lower part of the cloth there are weights 3, which hold the cloth against In this way, the cloths share water areas 26 and 27. the bottom of the water body. Council in two partially demarcated areas Next to the pontoons 2 there is one or more pumps 4 placed in top open, liquid pump boxes 5. When a pump 4 is switched on, water flows from the adjacent water area 26 into the pump box 5, which takes place partly through openings 6 to at the water surface and partly through openings 7 at the bottom close the bottom of the pump box. With this arrangement can be both liquid particles that are suspended in water in the water are pumped the drawers.

The pumps 4 pump water from the pump boxes S through pressure lines 8 and branch line 9 to one or more submersible only filter bags 10, arranged in the manner described above.

As the water passes through the walls 14, the pumped is filtered the water so that filterable material - in the applications described here cation mainly algae and plankton - remains in the bag, preferably on its inner walls, while the felt water, the clear phase, flows into the adjacent and surrounding water area 27.

As indicated in connection with Figs. 1 and 2. rises during filtration the water level 16 inside the bag in a a 10 15 20 25 30 35 453 564 6 in relation to the water level of the water area 15. When the the difference reached a maximum permissible value takes place flushing by means of the flushing pump 17, which passes through the lines 18 and 19 transfer the filtered material to one located on land receiving station 20. At the same time, as indicated in in connection with Figure 2, injection of compressed air into the filter the bags 10 through the lines 21 and 22 and the air blowing the nozzles 23.

The arrangements with cloths immersed in water and pumping through flushable filter bags together form a system, which is located in a body of water 25 delimits a water area 26 from which water is transported via the filter bags to another water area 27 whose contents are mainly filtered water. This arrangement gives rise to a certain circulation throughout the body of water 25 as illustrated race with flow arrows in Fig. 3. Convection currents, wind impact and temperature stratification with accompanying agitation effects, however, cause the circulation picture to be broken from time to time to another. This in turn leads to new amounts of algae and plankton is fed to the water area 26 for further pumping to the filtration step.

Fig. S illustrates how the purification system with flushable filter bags according to the invention can also be applied to watercourses or dams where the pontoon large, open lake areas, connection from the filter bags to land would be too long and expensive.

Instead, the pontoon system 2 is suspended in water. canvas 1 in this case an independently floating and towing unit that can be transported around the water area for filtration and removal of algae and plankton.

Pumps 4 in pump boxes 5 and filter bags 10 are used arranged according to the same principles as previously described, see Figure 2. Flushing lines 19 for transporting algae and planks tons and compressed air lines 21 must be used in this application things are placed on the lake bottom or mounted on floats on the water surface, as shown in Figure 5. 10 15 20 453 364 7 Another similar application is water purification in connection with fish farms. Food leftovers and fish feces are formed in large quantities quantities in the cultivation basins and constitute a nuisance and costly problems. With the present invention, to neutralize these pollutants by filtering in suitably arranged filter bags with associated flushing system. This can be applied to both sea- and land-based fish farms, according to Figure 6.

Previously described elements such as pumps ü - here though without pump boxes, pressure line 8, branch lines 9, filter bags 10, flushing pumps 17 and flushing lines 18 and 19 are provided within a defined area 27 which, as before, is filled with filtered water. Unfiltered water is pumped out the water area 26 by means of pumps à to the filter bags- 10 and then led through a conduit 30 to the basins or the inlet side of the ponds.

The invention is of course not limited to those above described embodiments, which can be modified in many ways way. For example, the flushing of the filter bags can be performed, i instead of with a pump arranged in each bag, by means of an external for the bag located pump, which sucks up the bag through a line content and transfer it to the point of receipt. Such a pump can be common to several filter bags.

Claims (7)

10 15 20 25 30 35 453 364 PATENT REQUIREMENTS Method for separating filterable particles from water, characterized in that a bag-shaped filter of a filter material suitable for separating the particles in question is placed in a body of water with the bottom of the bag-shaped filter located below the water surface and its opening above it. , that in the interior of the bag-shaped filter water charged with particles is to be filtered, whereby the water flows through the filter to the surrounding body of water, while the particles remain within the filter, and that a certain amount of particles has then collected in it. the bag-shaped filter, while the filter is maintained in the body of water, discharges the collected particles to a place separate from the body of water while flushing the filter by means of a flushing pump arranged inside the bag-shaped filter near its bottom. A method according to claim 1, in that the bag-shaped filter can be brought into water mass, which mainly consists of previously filtered water. 3. A method according to claim 1 or 2, characterized in that the discharge of “accumulated particles” begins when the water level within the filter as a result of the increase of the flow resistance through the filter material has risen to a predetermined value. Method according to one of Claims 1 to 3, characterized in that a stirring of the contents of the bag is carried out during rinsing and discharge, e.g. by air blowing and / or mechanical agitation. Method according to one of Claims 1 to 4, applied in the remediation of bodies of water in the form of lakes, watercourses and similar bodies of water, characterized in that substantially vertical and from the surface to bottom-going walls, which separate two water areas from each other, in one water area one or more bag-shaped filters are arranged in the specified manner and from the other water area water leads to the interior of the filter or filters for filtration, the two water areas being mainly without a direct flow connection from the latter area to the former area, and that the particles collected in the filter or filters are diverted to a separate collection station. Device for separating filterable particles from water, characterized in that a bag-shaped filter of a filter material suitable for separating the particles in question is placed in a body of water with the bottom of the filter located below the water surface and its opening above the water surface. , that a line is arranged for introducing water to be filtered in the interior of the filter and that a pump is arranged inside the filter and connected to a line for removal of particles collected in the filter to a place separate from the water mass during simultaneous flushing of the filter material. Device according to claim 6, characterized in that one or more filters of the type indicated are arranged in a first area of the water mass, that one or more pumps are arranged in a second area of the water mass and connected to pipes for introducing water from the second area into the interior of the filter or filters and that vertical walls are arranged in the body of water in such a way that direct flow from the second water area to the first water area is substantially prevented.