AU2010202403A1 - Device for purifying artificial bodies of water - Google Patents

Description

Translation re Australian Application 2010202403 Device for purifying artificial bodies of water Description The invention relates to a filtering system for processing water, particularly by biological means, with the aid of a filter body comprising a filter substrate layer, a water-distributing layer, a water-collecting layer, a system for distributing the water to be purified within the filter body by means of a closed system of pipelines, and a pressure line for supplying the water to be purified. The invention further relates to an arrangement of filtering systems of such type. The invention further relates to a separate water distributing system for filtering systems. In the case of artificial bodies of water, e.g. installations resembling lakes or ponds for swimming, for the garden, for fish ponds or for crawfish ponds, particularly high demands are placed on water clarity on the part of the user or owner. The natural surroundings of these bodies of water often subject the same to external nutrient inputs. Swimming activities of humans or deliberate supplementary feeding result in further nutrient contamination which can adversely affect the clarity of the water. It is customary to purify such bodies of water by pushing the formation of biofilms in a so called processing zone (filtering zone). A biofilm contains microorganisms that absorb the nutrients contained in the water to be purified and thus extract the same from the water (purification process). Such a processing zone is often a multilayered filter body comprising a filter substrate layer used for purification, a water-distributing layer supplying water to the filter substrate, and a water-collecting layer accommodating the purified water. The water-collecting layer can at the same time also act as a covering layer and be provided with aquatic plants. The water distributing and water-collecting layers are usually filled with appropriate substrates such as flint, and they frequently cause further pollution of the artificial water body as a result of their own nutrient-holding capacity. The biofilm can be present in the entire filter body, but is particularly concentrated in the filter substrate layer owing to the presence of suitable substrates.

Translation re Australian Application 2010202403 2 For the purification process, water is continuously supplied to the filter body from the body of water to be purified at a predefined rate. Due to the continual removal of nutrients by the biofilm, a clear-water stage is finally achieved. The organisms forming the biofilm require for their survival a sufficient supply of oxygen dissolved in water and therefore involve (active) aerobic biology. This active aerobic biology is maintained in a targeted manner, i.e. the administration of oxygen and the supply of nutrients with the aid of the water to be purified promote its growth and thus assist the filtering activity. Allowing microorganisms to die off and rinsing the biofilm on achieving the maximum growth density in a specific manner serve to reduce the overall balance of the nutrient circulation in the body of water. Otherwise, a nutrient backlash would take place in the case of uncontrolled morbidity of the microorganisms. The volume of water required for purification is sucked in from the body of water to be purified (mostly from the surface of the body of water). Extraction at the surface serves to filter out coarse floating materials such as leaves, needles, fruit, branches, or other floating refuse as a preliminary measure. The water sucked in is usually fed entirely or partially to the filter body by distribution on the pressure side of the pump ("on the pressure side" means before reaching, or beneath, the filter substrate layer). In the filtering zone, the water is distributed by local distributor shafts, distributor plates or other drainage-based pipes or portions of pipe that are disposed on the floor inside the filtering zone and are connected to the pumping-plant line on the pressure side thereof. This water-distributing construction comprising terminal output elements is only capable of distributing the pumped water unevenly within the filter body, which results in an irregular supply of oxygen and nutrients to the biofilm and thus in an irregular filtering performance. Entrained air, resulting, for example, from leakages in the line, the use of an incorrect pumping capacity (cavitation) or improper control thereof are factors that are likewise distributed throughout the filter body. The quantity of entrained air can be object related, that is, it varies depending on the individual design of the system. Due to the greater buoyancy of the air, low-resistant water channels are formed slowly but continuously in the filter substrate. Water channels are the buoyancy paths of the air bubbles through the substrate, through which the water can subsequently flow (due to the lower resistance). Such water channels are a hindrance to uniform distribution of the water in the substrate. An improved ability to distribute water can be achieved with the aid of a closed system of pipelines. An example of a filtering system comprising a closed system for water distribution Translation re Australian Application 2010202403 3 on the pressure side, that is, before the water reaches the filter layers, is disclosed in US 4,379,050 for a filtering system for use in fish-rearing ponds. This filtering system distributes the water by means of interconnected, parallel pipes over a large area in the filtering zone, the water emerging through orifices in the pipes. In this way the water is distributed considerably more uniformly across the filtering layer or filtering granules with or without microorganisms (bacteria). EP 1 038 435 A2 discloses another variant of a closed water distributing system in the form of arbitrarily arranged pipe manifolds that can be distributed over the filter bed area, orifices in the manifolds permitting discharge of the water and thus creating a uniform distribution of water in the active filtering layers. This also achieves a more uniform distribution of water in the filtering zone involving active aerobic biology. However, neither of the two prior documents deals with the problem of entrained air, which results in an uneven supply of oxygen and nutrients to the biofilm, not even when the distribution of water is initially uniform. Thus the disadvantage of these systems is that the volume of water intended for the total area of the filter body finds shorter escape routes through the substrate (hydraulic short cuts due to the formation of water channels, as explained above). As a result, individual regions of the filter can be cut off from the supply of oxygen and nutrients required for the biofilm organisms, due to which the latter die off. Hydraulic short cuts in the filter constructed as an aerobic filter thus result in anaerobic (oxygen-deficient) and thus undersupplied regions in the biofilter, due to which the biological filtering performance is reduced. The consequence is the release of nutrients bound to the biofilm as a result of the death of microorganisms and the permanent loss of filtering efficacy (water purification), which thus has an adverse effect on the quality of the water. Starting from the prior art described above, it is therefore an object of the invention to develop a filtering system of the type described at the outset such that the aforementioned problems can be avoided and an improved filtering performance can be achieved. This object is achieved for a filtering system of the type described above in that means are provided for the deliberate removal of the air entrained by the water to be purified before it reaches the filter substrate. This system proposed by the invention is a structurally self-contained interconnected piping system (water distributing system) which can be configured individually to suit the design of Translation re Australian Application 2010202403 4 the filtering zone. A horizontally laid-out system intended for water distribution ensures uniform water distribution in the filter body, particularly in the filter substrate layer, without any disturbing air fractions, since these are removed from the water before it reaches the filter substrate. Thus, the water channels explained above as being detrimental and thus the occurrence of hydraulic short cuts can be prevented, this ensuring a continual uniform supply of oxygen and nutrients to the biofilm and consequently uniformly efficient biofilm activity. Advantageously, the air entrained by the water to be purified is removed at a point as close as possible to the filter substrate, that is, immediately before the water reaches the filter substrate. This allows for a particularly efficient prevention of hydraulic short cuts. Alternatively, the deaerating means can be disposed in the pressure line if this is advantageous or even necessary, for example, due to structural environmental conditions. The means for removing the entrained air can advantageously be in the form of a riser pipe. This permits efficient removal of the air and makes it easy to provide control means for regulation thereof. Advantageously, control means are provided for manual or automatic operation. This allows for specific use of the deaerating means in changing conditions. Advantageously, the control means are in the form of a valve. In an additional advantageous embodiment, the water-distributing and/or water-collecting layers are substantially substrate-free in order to reduce the nutrient contamination in the body of water. A distributor element can be provided in the substrate-free region to ensure distribution of the water in a more efficient and more trouble-free manner than is possible by means of the conventional filler substrates (flint etc.). Advantageously, such a distributor element comprises a hollow system that ensures uniform water distribution in the piping system described above and can be regarded as being less resistant than substrates. This hollow system can be mat-like in design, for example. Conveniently, such distributor elements can be used and suitably installed in conjunction with the closed piping system on the pressure side and on the suction side, i.e. in the water distributing layer or the water-collecting layer. This ensures that this water-distributing and water-collecting system can be used efficiently for the intended tasks of water processing. It thus offers the advantageous option of reducing the space requirements for the height and Translation re Australian Application 2010202403 5 width of the filter bed area. It is advantageous when protective sleeves are provided on the riser pipe and/or the pressure line in order to stabilize the same against vibratory movements in the substrate region and thus counteract the formation of flow axes along the pipes. The pressure line itself need not be routed through the substrate and there is no necessity to prevent flow axes along the pressure line when the latter is routed through the ground up to the filtering system since this routing already absorbs vibratory movements. Vibratory movements are caused, for example, as a result of irregular pumping activity that can be triggered by pressure fluctuations or entrained air. Such vibratory movements in the substrate region can result in the formation of channels (substrate-free regions along the pipe walls) and thus in flow axes (hydraulic short cuts). Flow axes or hydraulic short cuts can, as explained above, adversely affect the uniform distribution of water in the substrate and are thus detrimental to the filtering performance. The projection of the protective sleeves firstly stabilizes the pipes against vibratory movements by engaging the substrate and additionally acts as a resistance to flow to counteract any flow axes that may occur in the substrate region along the pipes. The use of distributor elements allows for a multilayered construction of the filtering system, also when conventional filter bodies of the same dimensions are used. This multilayered construction makes it possible to pre-fabricate the filtering system as closed modular units comprising self-contained inflow and outflow units, in which only the relevant filter substrates are present. Stackable pre-fabricated filter bodies can be transported by building equipment without extensive exploitation of resources. They can be provided with plants or used without plants, as required. Furthermore, it is an object of the invention to retrofit conventional filtering systems in the manner proposed by the invention. This object is achieved by a closed water-distributing system as defined in claims 14 and 15. The integration of water-distributing systems of the invention in conventional water filters makes it possible for existing filtering systems to operate more efficiently. This makes it possible for cost-effective optimization of existing systems. The invention is explained below with reference to an exemplary embodiment illustrated in the drawings, in which: Fig. 1 is a diagram showing a filtering system comprising a closed water distributing system, I ranslation re Australian Application 2IUZUL24U3 b Fig. 2 shows an embodiment of the closed water-distributing system according to the invention, Fig. 3 shows a detail of the closed piping system shown in Fig. 2, Fig. 4 is a diagram of a conventional filter body comprising an integrated water-distributing system of the invention, and Fig. 5 is a diagram of a plurality of combined filter bodies of the invention. Fig. 1 shows an artificial body of water or pond 1, of which the water is to be purified and in which the water to be purified is sucked out through a suction line 3 connected to a pumping plant (P1) 2. The pressure line 4 connected to the pumping plant (P1) 2 is subdivided, if required, into at least two lines 5, 6. However, if the volume of water for charging the filter conforms to the pumping capacity of the pump, then only one pressure line 5 is sufficient for supplying the water to be purified to the filter body 24 (indicated in the drawing merely by the filter area 10 to show its position and orientation). If the pressure system comprises at least two lines 5, 6, the device is divided into a first filter pressure line 5 that can be regulated with the aid of a ball valve 7, and a second pressure line 6, the so-called by-pass line 6. The by-pass line 6 serves to measure the volume flow rate of the total quantity of water conveyed. The volume of water required for the filter can be adjusted by means of a water flow regulator 8. The excess water is pumped back into the pond. For example, this excess water may be used to form a fountain 9 before flowing back into the pond. If the filtering system includes an additional pump (P2) 14, the latter can be connected for the aforementioned maintenance purpose by means of a cut-off valve 18 to the pipeline section 5 or the pipeline 13 (not shown) in addition to the normal suction line 38 for the water to be purified. The desired flow path can be defined by means of a multiple-way cut-off valve 15. When it is desired to clean the pipes or wash the filter, the nutrient-rich water to be removed is directly discharged into a drain connection, sewer junction, or any other similar connection 33 by opening the cut-off valve 32. Otherwise, at least one pressure line 34 containing a cut off valve 31 is provided for water circulation during normal operation. It is likewise possible to operate the filter under suction power, instead of under pressure. The pipe section 13 designed as an air collector can also be used for pipe cleaning, filter Translation re Australian Application 2010202403 7 rinsing or maintenance of the filter body 24 and can be equipped accordingly, if necessary. For example, the air collector 13 is in this case routed back to the pond 1 in order to keep the water which is entrained by the air to be removed, in the water circulation. Fig. 2 shows the manner in which the filter pressure line 5, which is shown in the present embodiment as a horizontal pipe, is diverted toward the filter surface 10 to reach the base of the filtering zone, ideally in a vertical direction to suit the respective structural situation. Protective sleeves 19 serve to counteract vibratory movements of pipe sections in the substrate and thus the formation of channels through the substrates along these pipe sections. The protective sleeves 19 surround, in the present example, the pressure line 5 in the region of the inflow point 20 and the air collector 13 in the region of the riser pipe 11 and are in the form of annular collars. The collar serves firstly to engage the substrate such that significant vibratory movements are prevented or reduced, and secondly also acts as a resistance to any possible flow in axes along the pipes 5, 13 within the filter body 24 (not shown). The illustration of the projection is to be understood purely diagrammatically, that is, the actual design is governed by the actual requirements or facilities in each case. The water rate required for the filtering zone is pumped into the piping system 17 via inflow points 20. The arrangement and number of the inflow points 20 each depend individually on the way the filter area 10 is designed. The water 37 to be purified emerges through the orifices 21 in the closed pipeline 17 and thus flows into the filter body 24 (not shown). The location of the air collector 13 is likewise configured to suit the basic structural conditions. The collected air 22 is removed through a cut-off valve 12 in the most ideal manner in individual cases. In the case of automatic deaeration, the pipe section 13 is routed back into the pond 1 and a new, that is, alternative location for the cut-off valve 12 is determined (see reference numeral 16 in Fig. 1). Fig. 3 shows, in detail, the orifices 21 in the closed pipeline 17 shown in Fig. 2, through which the water emerges in the direction of the arrows 37. These orifices 21 can be in the form of holes, slots, or the like, but must be positioned below the horizontal center axis 23. The air 22 entrained by the water is transported along the upper arch of the vertically extending pipeline network 17. This air 22 transported in the piping system 17 collects in a riser pipe 11a and can be removed from the system manually or automatically via a cut-off valve 12.

Translation re Australian Application 2010202403 8 Fig. 4 shows a cuboid conventional filter body 24, which comprises a covering substrate or collecting substrate 36 as the uppermost layer, in which aquatic plants 28 may be present. The lowermost layer is formed by the water-distributing layer 26 containing an appropriate substrate to effect distribution of the water. The filter substrate 25 proper is located between these two layers. The piping system 17 of the invention, which is provided at the bottom of the filter body 24, is embedded in the substrate of the water-distributing layer 26. The water 37 freed beforehand from entrained air flows through the orifices 21 of the piping system 17 into the water-distributing layer 26 and thence toward the filter substrate layer 25. Following purification of the water in the filter substrate layer 25, the emerging purified water is collected in the water-collecting layer 36 and released from here into the environment, that is, into the body of water to be purified. The horizontally laid-out piping system 17 is designed to suit the structural requirements in individual cases and serves to achieve uniform distribution of the water to be purified. At least one riser pipe 11a (not shown in the figure) is disposed vertically at some point in the entire pipeline network (that is, including the supplying pressure pipe) and serves as an air collector for the entrained air 22 (not shown) before the water reaches the filter substrate layer 25. In this way, conventional water filtering systems can be easily developed according to the proposal of the invention. Fig. 5 shows, as a further possible embodiment of the invention, a combination of a plurality of filter bodies 24 as shown in Fig. 4, only the uppermost and the lowermost filter bodies 24 being illustrated in this figure. The dots indicate the presence of an arbitrary number of additional filter bodies 24 disposed therebetween. In this exemplary embodiment, all the water-distributing layers 26 and the water-collecting layers 36 with the exception of the uppermost water-collecting layer 36 are equipped with distributor elements 29a and 29b respectively in the form of a system of cavities. This uppermost water-collecting layer 36 is equipped only with substrate and serves as the covering layer for the accommodation of aquatic plants 28. The distributor elements 29b in the remaining water-collecting layers 36 serve to transport the purified water 35 to the discharge line 27b. This arrangement of the layers serves merely as an example and any number of other combinations with or without substrates and with or without hollow distributor elements Translation re Australian Application 2010202403 9 29a, 29b and with or without aquatic plants 28 is possible. A closed and thus stackable filtering zone comprising an arbitrary number of elements can be constructed on account of the arrangement of feed lines 27a, shown by way of example, for the water 37 to be purified and the discharge lines 27b for the purified water filtrate 25 collected. This is indicated by the dots between the upper and lower levels. The desired de aeration described with reference to Fig. 2 (not shown here) is likewise provided. It is thus possible to construct the filter body as a stack of closed filter units, the uppermost filter unit being provided with aquatic plants. The filter body, which is thus constructible with or without plants, can be produced such that it is on the whole more compact and lighter in weight. The significant reduction in weight makes it possible to create a portable pre-fabricated, stackable filter and to install the same efficiently, in terms of time, as measured against to the prior art. The embodiments shown in the figures are only examples of possible implementations of the idea of the invention. The essential feature of the invention is the uniform distribution of the water to be purified within the filter layers, particularly in the filter substrate layer, and the prevention of hydraulic short cuts in the biofilter by means of the deliberate removal of the air entrained by the water to be purified before it reaches the bioactive substrate layer. This deaeration can naturally also be effected before the water reaches the filter body.

Translation re Australian Application 2010202403 10 Device for purifying synthetic bodies of water List of reference numerals or characters 1 body of water/pond, such as a pond for swimming, a fish pond, a crawfish pond 2 pump station P1 3 suction line P1 4 pressure line P1 5 pressure line to filter 6 second pressure line (by-pass line) 7 ball valve 8 water-flow regulator 9 fountain 10 filter area 11 de-aerating means 11a riser line 12 cut-off valve 13 pipeline section, air collector 14 pump station P2 15 multiple-way cut-off valve 16 cut-off valve 17 closed piping system 18 cut-off valve 19 protective sleeves 20 inflow point 21 orifices 22 air 23 horizontal center axis 24 filter body 25 layer of filtering material (filter substrate) 26 water distributing layer (water distributing substrate) Translation re Australian Application 2010202403 11 27a supply line 27b discharge line 28 aquatic plants 29a distributor element (in water distributing layer) 29b distributor element (in water collecting layer) 30 pipe 31 cut-off valve 32 cut-off valve 33 drain connector, for example to sewer 34 pressure line 35 wavy arrow: flow of water filtrate (purified water) 36 water collecting layer (cover region/water collecting substrate) 37 wavy line/arrow: flow of water to be purified 38 suction line

Claims (15)

1. A filtering system for the treatment of water, more particularly by biological means, incorporating a filter body (24) comprising a filter substrate layer (25), a water distributing layer (26), a water-collecting layer (36) and a system for distributing the water to be purified within the filter body (24) by means of a closed piping system (17) and further comprising a pressure line (4, 5) for feeding in the water to be purified, characterized in that that means (11) are provided for deliberate removal of the air (22) entrained by the water to be purified before the latter reaches said filter substrate (25).

2. A filtering system as defined in claim 1, characterized in that said means (11) are disposed such that they remove the air just before the water to be purified reaches said filter substrate (25).

3. A filtering system as defined in claim 1, characterized in that said means (11) are disposed in said pressure line (4, 5).

4. A filtering system as defined in any one of claims 1 to 3, characterized in that said means (11) are in the form of a riser line (11a).

5. A filtering system as defined in any one of claims 1 to 4, characterized in that said means (11) are controllable.

6. A filtering system as defined in claim 5, characterized in that Translation re Australian Application 2010202403 13 the control means for said means (11) are in the form of a valve (12, 16) in the riser line (11a).

7. A filtering system as defined in any one of claims 1 to 6, characterized in that the water distributing layer (26) and/or the water-collecting layer (36) are substantially free from substrate.

8. A filtering system as defined in claim 7, characterized in that the water-distributing layer (26) and/or water-collecting layer (36) that are substantially free from substrate have a distributor element (29a, 29b).

9. The filtering system as defined in claim 8, characterized in that the distributor element (29a, 29b) is in the form of a system of cavities which is poor in nutrients.

10. A filtering system as defined in any one of claims I to 9, characterized in that protective sleeves (19) are provided on the riser line (11, 11a) and/or pressure line (5), in order to protect the same against vibratory movement in the substrate region and to counteract the occurrence of flow axes along the pipes (5, 11, lla).

11. A filtering system as defined in claim 10, characterized in that the protective sleeves (19) are in the form of overhangs that substantially surround the pipe to be protected.

12. A system comprising a plurality of filtering systems as defined in any one of the previous claims, in which at least two filtering systems as defined in any one of the previous claims are coupled together.

13. The system as defined in claim 12, in which the filtering systems are stacked one above the other.

14. A closed water-distributing system (17) for a filtering system for the water treatment of bodies of water, Translation re Australian Application 2010202403 14 characterized in that means (11) are provided for deliberate removal of the air (22) entrained with the water (37) to be purified before the latter reaches said filter substrate (25).

15. The water distributing system as defined in claim 14, characterized in that said means (11) are designed as defined in any one of claims 2, 4, 5, or 6.