FI120984B - Method and system for purifying water - Google Patents

Description

METHOD AND SYSTEM FOR CLEANING WATER-METHOD OCH SYSTEM FÖR RENGÖRING AV VATTENDRAG

TECHNICAL FIELD OF THE INVENTION

The invention relates to a method and system for purifying water, as disclosed in the preambles of the independent claims below. The invention particularly relates to a new way of removing solids from flowing water such as a ditch.

10 BACKGROUND OF THE INVENTION

For example, agriculture and peat production produce unwanted substances such as solids, nutrients and dissolved organic matter in waterways. Uncleaned, these can cause eutrophication of the water body, sedimentation of the bottom, changes in the aquatic biota or clouding of the water body. A large number of different cleaning methods have been developed. However, there is still a need to provide a simple, easy-to-use, and at the same time effective, method for purifying water bodies such as ditches.

One known way to remove solids from flowing water is to place a dam or other barrier to flow across a ditch or stream. Solids accumulate behind the retarder, which can be periodically removed, for example, by pumping or dredging with an excavator. Known solutions are often expensive. Pumps and other actuators require service to operate. A dredging machine is often difficult to reach beside a dam.

25

US6332737 discloses a method and apparatus for purifying water.

PURPOSE AND BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to reduce or even eliminate the above-mentioned problems in the prior art.

2

In particular, it is an object of the present invention to provide a simple, easy to use and at the same time relatively effective water purification method.

In particular, it is an object of the present invention to provide an arrangement for removing solids from flowing water such as ditches, streams and rivers.

Among other things, to accomplish the above purposes, the method and system for purifying water according to the invention is characterized in what is stated in the characterizing parts of the appended independent claims.

The application examples and advantages mentioned herein apply, mutatis mutandis, to the method and system according to the invention, although not always explicitly mentioned.

Typically, when purifying a watercourse according to the invention, a water filter having at least partially a filter volume provided with filter cloth walls is held in the water, wherein a portion of the filter cloth is held at least substantially parallel to the bottom, thereby settling the solids thereon; - collecting the solids in the water volume into the filter volume, - removing the solids from the water by removing the filter from the water so that the solids remain substantially within the filter volume of the filter and water is drained from the filter volume through the filter cloth.

Typically, according to the invention, water is purified by a system comprising a 30 filter having a filter volume for solids remaining in the filter, wherein at least a portion of the walls of the filter volume is of filter cloth.

3

A typical filter according to the invention is arranged to be lifted out of the water so that the solids remain mainly in the filter volume of the filter and at the same time water flows out of the filter volume through the filter cloth.

5 For the purposes of this text, body of water means particularly flowing bodies of water, such as streams, streams and rivers. The invention is also applicable to other water bodies.

The filter of the invention may comprise a variety of filter cloths. The filter cloth has a mesh size that is permeable to water, but at least not all of the solids in the body of water for removal can pass through the fabric. At least a portion of the filter cloth is provided in normal operation with a main transverse portion relative to the direction of flow of the water to stop the solids. By predominantly transverse is meant here, for example, the filter vertical of the predominantly vertical and transverse direction of the trench 15.

The fact that a filter has a filter volume means that the solid suspended by the filter is at least partially sedimented inside or on top of the filter, i.e. the filter volume. Typically, the filter has a portion of the principal horizontal or parallel to the bottom of the 20 major bodies of water. For example, a planar filter cloth may be disposed in the waterway with its upstream portion resting on the bottom of the waterway, suitably secured to the bottom, and the lower end of the filter cloth upright transverse to the general flow direction of the waterway.

25

In one embodiment of the invention, the filter volume is bag-like and has an orifice and water is arranged to flow into the filter volume through the orifice. The filter may be bag-shaped, that is, comprise at least a bottom portion and sides connected thereto that surround a bag-like filter volume. The bag-like filter volume 30 is led by at least one orifice, or filter mouth. In this case, the water is typically arranged in the mouth and flowing into a bag-like filter volume. Typically, the bag-like filter is placed on the side of the body of water, that is, with the mouth of the bag in an upright position and 4 transverse to the general direction of flow of the body of water. At least one side of the bag is then typically at or at least substantially parallel to the bottom of the body of water. The bottom portion of the bag is then typically about the length of the side walls of the bag downstream of the mouth.

5

The filter according to the invention may serve as a bag or sack currently used in the market for other purposes, e.g. FIBC. In this case, the mouth of the bag may serve as said filter mouth and the volume of the bag as said filter volume. The sack may be made mainly of nonwovens, for example glass nonwovens. The volume of the bag may be, for example, 0.5-3 m3 or 1-2 m3. The cross-section parallel to the opening of the sack may be, for example, a circle or a rectangle. The bottom or mouth opening may be, for example, 0.5 to 2 m or 0.75 to 1.5 m in diameter. The side walls of the sack may, for example, be 0.5 to 3 m or 1 to 2 m. 15 to clean most ditches or other flowing waterways. Thanks to their ready-made lifting loops, for example large sacks are particularly well suited for use in accordance with the invention in a method whereby the sack is lifted out of the water, if necessary.

20 It has now surprisingly been found that removal of solids from water works does not require expensive and often complex equipment. With the invention, the removal of solids from water is easy and inexpensive. The filter system according to the invention is reliable. If necessary, it can be easily removed completely, for example during winter or maintenance work. If pre-made bags are used as filter 25, emptying and renewing the filter is very easy and inexpensive.

In one embodiment of the invention, a second filter cloth having a mesh size smaller than the mesh size of the bag is provided inside the bag. Selecting another 30 filter fabrics can influence the quality of solids to be removed from the water.

5

In one embodiment of the invention, once the filter has been removed from the water system, it is at least substantially emptied of solids and then returned to the water system to collect the solids. For example, various known nonwoven materials withstand very long periods of use.

5

In one embodiment of the invention, the filter is raised at its edges. Suitable lifting points have been provided at the edges of the filter for easy lifting. In one embodiment of the invention, lifting means, such as rings, loops or hooks, are provided at or near the edge of the filter volume mouth opening to facilitate lifting. The filter can be lifted out of the water by a variety of devices, such as a chain, rope, wire or the like attached to the lifting bar of a tractor or other implement at suitable lifting points.

In one embodiment of the invention, the filter is attached to a support, such as piles, attached to the edges of a body of water, such as a ditch, or to the bottom of a body of water. Piles or other supports are then typically secured to the edges or bottom of the body of water with a firm and substantially immobile motion. In one embodiment, openings and closures are provided between the piles or other supports and the filter, such as a slot 20 to which the filter mouth can be attached. The filter, for example around its orifice, may have a counterpiece suitable for the fastener on the support. The attachment can be secured by various connectors, e.g. bayonet connector. It is also possible to attach the filter to the support by means of ropes, cables or the like, for example, directly to a support attachment point 25 on the edges of the ditch or other body of water.

In one embodiment of the invention, the filter is supported by a dam provided in a water system, by means of which water is directed to the filter volume of the filter according to the invention. The dam may be made of a material impermeable to water, for example concrete, plywood or wood. The dam can be arranged to cover the entire body of water, such as a ditch, except for the filter inlet. This allows all water flowing through the water system to be filtered.

6

In one embodiment of the invention, the amount of water flowing into the filter is controlled by changing the size of the orifice. Thus, closure means for changing the size of the orifice may be provided in connection with the filter. In one embodiment, the closure means is attached to a support to which the filter 5 is attached, for example to a dam.

In one embodiment of the invention, the mouth opening is resized by means of a movable closure disposed between different positions placed in front of the mouth opening. The shutter may be, for example, a plate movable on rails such as rails or slots, a hatch 10 or the like. The shutter may also be pivotable, for example, to pivot about a vertical or horizontal axis! hinged door or equivalent.

In one embodiment of the invention, the surface height or flow rate of the body of water is measured and the position of the mouth closure means is controlled according to the height or flow size of the body of water. The water surface elevation gauge or flow gauge may be automatically coupled to the orifice closure means, whereby the size of the orifice is automatically controlled according to the water surface level or flow rate. The water level gauge may be, for example, a float valve, whereby when the water level rises, the float sensor, i.e. the float 20, rises upwards and, through a suitable float mechanism, closes the filter mouth as a function of water level. In some embodiments of the invention, water access to the filter is restricted or prevented during high water or high flow. By closing the orifice, solids are prevented from leaching out of the filter volume, for example, by the action of flood water.

In one embodiment of the invention, a water purifying chemical is supplied to the water at the filter. In one embodiment, a water purification chemical container and a dispensing device 30 are then provided in connection with the filter for supplying the water purification chemical from the container to the water body. For example, ferrous sulfate or other precipitating chemical may be suitably dosed to promote the precipitation of nutrients, such as phosphorus, into the filter of the invention. If the properties of the body of water, such as level, flow, solids, or amount of a particular ingredient, are measured with a suitable meter, the chemical dosage can be linked to the values obtained from the meter.

5 BRIEF DESCRIPTION OF THE FIGURES

The invention will now be described in more detail with reference to the accompanying schematic drawing in which

Figure 1 illustrates one embodiment of the invention mounted in a ditch and viewed from above, Figure 2 shows a side view of Figure 1,

Figure 3 illustrates another embodiment of the invention mounted in the ditch and illustrated in the direction of the ditch,

Figure 4 shows a third embodiment of the invention mounted in a ditch and viewed from the side, Figure 5 shows a fourth embodiment of the invention mounted in a ditch and in the direction of the ditch, and

Figure 6 shows a fifth embodiment of the invention mounted in a ditch and viewed from the side.

20 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the sake of clarity, corresponding parts of different embodiments are designated by like reference numerals. The flow of water is represented by arrows.

Figures 1 and 2 show a system 1 according to the invention for cleaning a water system 25 comprising a filter cloth 2. The filter cloth 2 has a substantially rectangular shape. In Figure 1, the filter cloth 2 is depicted by a dashed line. The first end 3 of the filter cloth is rested by the weights 4 on the bottom 6 of the trench 5 substantially parallel to the bottom. At a distance from the first end 3, for example 1-5 m, downstream there is one end 7 of the filter cloth 30 which is attached to the float 8. The float keeps the other end 7 close to the water surface 9 of the ditch. to lateral. There are, of course, several alternative solutions to the design of the float.

8

Weights 4 are also attached to the filter cloth 2 near its other end 7 to assist in maintaining the second end 7 of the cloth 2 in a substantially vertical position. Figure 2 shows how the center of the fabric is folded 10 approximately below the float 8. Thus, the filter cloth is sufficient up to the surface, even if the height of the water surface is slightly varied. In addition to the float 8, additional floats 11 are provided in the vicinity of the water surface 9, which stabilize the float 8 mainly in the direction of the ditch.

The water in the duct 5 can pass through one end 7 of the transverse vertical filter fabric with respect to the main flow direction of the water 10. At least not all of the solids carried by the water pass through the filter cloth, but the solids are sedimented on the part lying at the bottom of the filter cloth. This space 12 is referred to herein as the filter filter volume.

15 means are provided at the edges of the filter cloth 2 to facilitate its removal from the water. For example, floaters may be provided at the first end 3 of the filter which may be inflated if desired. Thus, when lifting the filter 2 out of the water, the floats 13 may first be inflated with air, whereby the edges of the filter cloth will rise to the surface. The float can rotate all 20 edges of the fabric 2. The members 13 may also be loops or hooks provided at the edges of the fabric 2.

Figure 2 shows a bottom dam 14. The system 1 according to the invention works well with the bottom dam 14 or a corresponding water flow retardant device 25. The solids carried with the water are sedimented in the filter volume 12 of the filter according to the invention. According to the invention, the solids are easily removed from the water. This can reduce the frequency of dredging the bottom of the dam the upper side. The bottom dam 14 or the like is easily arranged to support the filter system 1 according to the invention.

Figure 3 illustrates one embodiment of the invention mounted in a ditch and illustrated in the direction of the ditch. The figure shows a dam 15 constructed across the ditch, the edges of which are embedded in the ground surrounding the ditch 16. The edges of the triangular dam 15 9 below the ground are shown in broken lines. The dam 15 has a flow opening 17. The dam can be made in many different ways, but one simple way is to make it from plywood, such as water plywood, or some other sheet-like material, the edges of which are sealed to the edges of the water body. In the situation of the figure, the water surface 9 reaches near the upper edge of the flow opening 17. The filter according to the invention can be attached to the edges of the flow opening 17. For example, if the filter is bagged and provided with an orifice, the flow orifice may be arranged to be approximately the size of the orifice. In this case, for example, the so-called. it is relatively easy to attach a sack filter made of a large bag to 10 dams. With the help of the dam 15, even all the water in the body of water can be directed to the flow opening 17 and thus to the filter. Figure 3 shows in dashed lines the edges of the filter opening 19 behind the dam 15. The water flowing from the flow port 17 is thus introduced into the mouth port 19 and into the bag filter. One filter 18 and a solution for arranging the filter 18 in connection with the dam 15 15 are shown in Figure 4.

Figure 4 shows a system 1 in which a bag-like filter 18 is attached to the dam 15 from its orifice 19, and a plate-like flange or collar 20 is provided around the orifice 19 that is easily secured by fastening means 21 to the flow port 17. In the example shown, the filter orifice 19, i.e. the opening at the inside edge of the collar 20, is larger than the flow orifice 17 in the dam, so any water flowing from the orifice 17 can easily enter the filter 18. There are many different ways of attaching the For example, a slot 23 can be provided between the fastening means 21 of the dam 15 and 25, in which the collar 20 can be slidably slid.

The bag filter of Figure 4 is, for example, a so-called "filter" commercially available. a large sack having a flange or collar 20 attached to its mouth opening The collar 20 is arranged upstream of the ditch 5 and the bottom 24 of the sack is substantially vertical downstream of the ditch. One side 25 of the bag rests under the influence of the weights 4 on the bottom 6 of the ditch, substantially parallel to the bottom. The other side 26 of the bag rests on floats 27 near the water surface 9, substantially parallel to the surface.

10 A filter volume 12 is formed inside the bag, into which the solids carried with water are sedimented. The sedimented solid is depicted by dashed line 28. In the dam 15 of Figure 4, a dosing tank 29 of a precipitating chemical, e.g. ferrosulphate, is mounted above the surface, downstream of the dam, by controlling the position of the shutter 30.

When the filter 18 is emptied, the collar 20 of the orifice is first detached from its fastening means 21. The collar 20 or its vicinity is grasped and lifted, for example, by a tractor lifting boom. Collar 10 may be provided with, for example, lifting loops to facilitate gripping. When raised near the orifice, the solids contained in the filter volume 12 remain mainly in the filter 18. The water in the filter may first be drained through the filter cloth into the ditch before the sack is emptied into, for example, a tractor trailer or field. An empty filter bag will be replaced or replaced.

15

The flood may cause the solids to leach out of the filter 18 or even the filter 18 to become detached from its mounting means. Figures 5 and 6 show two solutions for limiting the amount of water flowing into the filter 18 as the water level 9 rises.

20

Figure 5 shows a system 1 in which a barrier 15 of the flow opening 17 in the dam is attached to a dam 15 similar to that shown in Figures 3 and 4. The main vertical guide rails 30 are attached to the dam, on the upper side thereof, by means of pins 31 provided with a closing hatch 32 for moving the vertical track. The closing hatch is slightly larger than the flow opening 17. In its lower position, the closing port 32 completely covers the flow opening 17. In its uppermost position, the shut-off door 23 is completely off the front of the flow opening 17. The rails are positioned so close to the dam 15 that the shut-off hatch in the lower position prevents the flow of water through the flow opening 17 at least substantially. The figure schematically illustrates how the so-called locking door 30 is connected to the shutter door. The float device 33. The float has a lever 35 pivoting about a shaft 34 supported on the dam. The lower end 36 of the lever 34 is secured to the shutter door 32. The upper end 37 of the lever 34 has a floating float 38 floating lowering and at the same time closing flap 32 closes. In the situation of Figure 5, the water level 9 has risen close to the upper edge of the dam 15 and the shut-off hatch 32 is almost in its lower position.

Fig. 6 is a side elevational view of a system 1 in which a sack-like filter 18 is disposed removably between a pile 39 formed on the bottom of two ditches 5. Unlike the solutions described above, in Figure 6, the float device 33 directly controls the size of the sack mouth 19. The lower end 36 of the lever 35 is now secured directly to the upper edge 40 of the mouth opening 19. The upper edge 40 thus moves up or down with the water surface 9. The lower edge 41 of the orifice is arranged approximately in place, for example by the effects of the weights 4 holding the sack at the bottom. Thus, as the water surface 9 moves, the size of the mouth 19 of the sack changes and thus the amount of water flowing into the filter 18 varies. The solution shown in Figure 6 does not require a dam or similar structure. Of course, the piles 39 must be sufficiently supported 15 to withstand the load of the flowing water. Fig. 6 shows the lifting loops 13 arranged near the edge of the mouth, from which it is easy to lift the filter when emptying it.

The figures show only a few embodiments of the invention. The figures do not separately illustrate matters of secondary importance, known per se, or obvious to one skilled in the art, such as any support structures which may be required by the invention. For example, the lever arrangements shown in Figures 5 and 6 are merely exemplary solutions that can be replaced by various automations. It will be apparent to one skilled in the art that the invention is not limited to the examples above, but that the invention may vary within the scope of the claims set forth below. The dependent claims disclose some possible embodiments of the invention and are not to be construed as limiting the scope of the invention as such.

Claims (13)

A method for cleaning a watercourse in which - in the watercourse a filter (2, 18) having an at least part with walls 5 (3, 7, 24, 25, 26) of filter fabric provided with filter volume (12) is held, - the water of the watercourse (5) is directed into the filter volume and out therefrom through the filter fabric, - solid material (28) contained in the watercourse is collected in the filter volume (12), - solid material collected by means of the filter (2, 18) is removed from the water feature, - a portion (3, 25) of the filter fabric is poured onto the bottom (6) of the water stream at least mainly in the bottom direction, whereby solid material is sedimented thereon, - the solid material is removed from the water feature, so that the filter ( 18) is lifted away from the water stream, so that the solid material is mainly poured into the filter volume (12) of the filter, and that water flows out of the filter volume through the fabric (3, 7, 24, 25, 26) characterized by - water of a flowing stream of water is guided into the filter made of fabric oxygen volume (12) by directing water by means of a substantially water impermeable dust (15) via the mouth opening (19) of the filter-like filter into the filter volume (12). Method according to claim 1, characterized in that - the filter (12) is lifted at its edges. 25 3. A method according to claim 1 or 2, characterized in that when the filter is lifted off the water stream - it is at least essentially emptied of solid material and - it is returned to the watercourse to collect solid material. 30 Method according to any one of the preceding claims, characterized in that - water cleaning chemical (29) is measured in the water stream at the filter. Method according to claim 1, characterized in that - the amount of water flowing into the filter is controlled by changing the size of the mouth opening (19). Method according to claim 5, characterized in that - the size of the mouth opening is changed by moving between different positions a closure (32) which is in front of the mouth opening. 10 Method according to claim 6, characterized in that - the height of the water surface (9) or the volume of the flow is measured, - the position of the closure (32) is controlled according to the height of the water surface or the volume of the flow and thus prevent solid matter from being washed away from the filter volume. (12) for example due to high tide. Apparatus (1) for cleaning a watercourse comprising - a filter (2, 18) having a filter volume (12) for solid material (28) remaining in the filter, at least part of the walls of the filter volume (3) , 7, 24, 25, 26) are of filter fabric, - the filter is arranged to be lifted away from the water funnel so that the solid material mainly stays in the filter volume (12) of the filter, and that water simultaneously flows out of the filter volume through the filter fabric ( 3, 7, 24, 25, 26) characterized in that 25. the filter volume (12) is similar and has a mouth opening (19), - the water is arranged to flow into the filter volume via the mouth opening. Device according to claim 8, characterized in that at the edge (20) of the mouth opening of the filter volume (12) of the filter or near the edge there are lifting tools, such as rings or hooks, to facilitate lifting. Device according to any one of the preceding claims 8-9, characterized in that it comprises - a substantially water impermeable dust (15) for controlling the water of the flowing water into the filter volume (12), 5. fastening means (21) between the dam and the filter, for attaching the filter to the pond in a removable manner. Device according to any of the preceding claims 8-10, characterized in that it comprises 10. closure means (33, 32) for changing the size of the mouth opening. Device according to claim 11, characterized in that - the closure means comprises a closure (32) which can be moved between different positions in front of the mouth opening (19). 15 Device according to claim 11 or 12, characterized in that it comprises - a height meter for the surface of the watercourse (9) or a meter which measures the volume of the flow, which is coupled to the closing means (33, 32) of the mouth opening to control the size of the mouth opening according to the height of the surface of the watercourse or the volume of the flow, whereby solid material is prevented from being washed away from the filter volume (12) for example due to high water. Apparatus according to any of the preceding claims 8-13, characterized in that it comprises 25. a water cleaning chemical container (29) and a dosing apparatus (30) for supplying water cleaning chemical from the container to the water supply to the system (1).