MODULAR BIO BED AND VENTILATED SYSTEM FOR WASTE WATER TREATMENT

Abstract

In a method for treatment of waste water, a module (5) is used which includes a number of carrier elements (7) arranged in a sandwich structure and configured to be perfused a flow of waste water. The module (5) further has a number of partitions (8) arranged between carrier elements (7) and configured to direct the flow of waste water through the module (5). The module (5) may also be used in a system together with an air supplying device (20) and a waste water vessel. The air is supplied to the module (5) by the air supplying device (20).

Claims

1. A module for treatment of waste water, comprising: a number of carrier elements arranged in a sandwich structure, said carrier elements being configured to be perfused by a flow of waste water; and a number of partitions arranged between said carrier elements, said partitions being configured to direct the flow of waste water through the module.

2. The module as claimed in claim 1, wherein the carrier elements and the partitions are configured to be covered by microbial growth.

3. The module as claimed in claim 1, wherein the partitions are arranged to direct the flow of water in a meandering manner through the module.

4. The module as claimed in claim 1, wherein each carrier element comprises a plate of irregularly twisted filaments.

5. The module as claimed in claim 1, wherein the partitions comprise sheets of geo textile.

6. The module as claimed in claim 1, wherein the partitions are semi-permeable to water.

7. The module as claimed in claim 1, further comprising a distribution pipe for delivering the waste water to the module.

8. The module as claimed in claim 1, further comprising an air inlet channel and an air outlet channel for supplying oxygen to microbes.

9. A method for treatment of waste water, comprising the steps of: a) providing a module according to claim 1; b) supplying waste water to the module, wherein the water travels through the module.

10. The method as claimed in claim 9, further comprising the step of providing a suitable environment for microbial growth in the module, preferably by supplying oxygen and moist to the module.

11. The method as claimed in claim 10, wherein the water partly passes through the partitions and partly travels through the carrier elements of the module such that the water passes the microbes purifying the water.

12. The method as claimed in claim 9, further comprising the step of supplying air to the module by means of an air supplying device.

13. The method according to claim 12, further comprising the step of leading the air supplied to the module by the air supplying device through an air conduit, such that said air is diverted from said module into a waste water vessel.

14. The method according to claim 13, wherein air is supplied to generate an overpressure in the vessel, such that ventilation of said vessel is eased.

15. A carrier element to be included in a waste water treatment module as claimed in claim 1, said carrier element comprising irregularly twisted filaments.

16. (canceled)

17. A waste water treatment system, comprising a waste water vessel and at least one module as claimed in claim 1.

18. A ventilated system for waste water treatment, comprising a waste water vessel, a waste water treatment module as claimed in claim 1, an air supplying device connected to an air inlet channel of the module, and an air conduit configured to lead air from an air outlet channel of said module to an air inlet of said vessel.

19. The system according to claim 18, wherein the waste water vessel is arranged at least partly below a ground level.

20. The system according to claim 18, wherein the waste water vessel is a septic tank or a sludge separator.

21. The system according to claim 18, wherein the module is configured to receive air through said air inlet channel and to lead said air out of the module through said air outlet channel.

22. The system according to claim 18, wherein a first end portion of said air conduit is connected to the air outlet channel of the module, and wherein a second end portion of said air conduit is connected to said waste water vessel.

23. The system according to claim 18, wherein said air inlet of the vessel is located above a water level of the vessel.

24. The system according to claim 18, wherein the vessel further comprises an air outlet configured to lead air to a ventilation valve.

25. The system according to claim 18, wherein the module is arranged in a bio bed.

26. The system according to claim 18, wherein the air supplying device is one of a compressor, a membrane pump or an air pump.

27. A kit for providing ventilation to a waste water treatment system including a waste water treatment module and a waste water vessel, said waste water treatment module, comprising a number of carrier elements arranged in a sandwich structure, said carrier elements being configured to be perfused by a flow of waste water; and a number of partitions arranged between said carrier elements, said partitions being configured to direct the flow of waste water through the module; and said kit comprising an air supplying device and an air conduit configured to feed air from the waste water treatment module to the waste water vessel.

28. (canceled)

Description

BRIEF DESCRIPTION OF THE D WINGS

[0043] Embodiments of the invention will be described in the following; references being made to the appended diagrammatic drawings which illustrate non-limiting examples of how the inventive concept can be reduced into practice.

[0044] FIG. 1 is a perspective view of a waste water purification system;

[0045] FIG. 2 is a perspective view of a bio module in accordance with an embodiment;

[0046] FIG. 3 is a cross section illustrating the bio module in FIG. 2 in a bio bed assembly;

[0047] FIG. 4 is a perspective view of a portion of a carrier element;

[0048] FIG. 5 is a perspective, partial view of a carrier element with a geo textile and a net according to an embodiment;

[0049] FIG. 6 is a cross section of the module shown in FIG. 2;

[0050] FIG. 7 is a cross section similar to FIG. 6 showing a bio module in accordance with a further embodiment;

[0051] FIG. 8 shows a ventilated waste water purification system; and

[0052] FIG. 9 shows a ventilated waste water purification system adjacent to a building.

DETAILED DESCRIPTION

[0053] With reference to FIG. 1, a first version of a waste water treatment or purification system 1 is shown. The system 1 comprises a septic tank or sludge separator 2 with an inlet 3 for untreated waste water and an outlet 4 for water treated by the sludge separator 2 (particle sedimentation) and to be further treated. The purpose of the sludge separator 2 is to separate particle impurities from the water flowing there through, since the particle impurities are undesired in the following steps of the system 1. Furthermore, the system 1 further includes a waste water purification apparatus or module 5 in which the waste water is purified before it is discharged via a discharge pipe 6. In the shown embodiment, the waste water purification module 5 is arranged approximately 0.5 m below ground level G. The module 5 is covered by a protective rubber sheeting 21 on the side surfaces and on the top and bottom sides (see FIG. 3). On top of the module 5 a protective sheet of geo textile (not shown) is provided, and the module 5 is covered by soil mass (not shown).

[0054] In other embodiments, the module 5 may be arranged on other depths below the ground G, or on top of the ground G. The sludge separator 2 canas an examplebe of the kind disclosed in WO 2000/004972A1 developed by the present inventor. However, also other types of particle separating units can be installed before or upstream the water purification module 5.

[0055] Now, the waste water purification module 5 will be described in more detail with reference to FIGS. 2 and 3. The module 5 comprises a number of carrier elements, in this embodiment in the shape of plates 7, which will be explained in more detail later on. The carrier plates 7 are stacked vertically on top of each other, such that layers are formed. Between each layer of carrier plates 7 partitions 8 are sandwiched. In the disclosed embodiment, the partitions comprise sheets 8 of water permeable geo textile, for instance made from polyethylene. The geo textile sheets 8 are arranged in an overlapping manner amongst the different levels of carrier plates 7, such that they do not cover the entire surface of a carrier plate 7. Instead, they are arranged to cover a predetermined area between each pair of carrier plates 7. In the shown embodiment, between every other layer of carrier plates 7, the geo textile 8 is provided as a strip 8a in a mid area of the plate 7, not reaching all the way out to long sides 7a of the plate 7.

[0056] Moreover, between the remaining pairs of carrier plates 7, two strips 8b of geo textile are provided along each long side 7a of the plates 7, leaving a section in the middle without geo textile coverage. The strips 8a of geo textile provided in the middle area of the plates 7 are wider than the part of the neighbouring plate pair not being covered by geo textile, i.e. the area between the strips 8b located along the long sides 7a of the plates 7. Similarly, the strips 8b are wider compared to the area not covered by geo textile in a neighbouring plate pair. Thus, a kind of labyrinthine path is formed through the module 5 by means of the geo textile sheets 8a, 8b.

[0057] The purification module 5 further comprises an elongate distribution pipe 9 which is connected to the outlet 4 of the sludge separator 2 and which is disposed at the top of the stacked carrier plates 7 making up the module 5. The distribution pipe 9 has a number of perforations 18a, 18b along its length such that the water to be purified can reach the whole extension of the module 5. Furthermore, the module 5 comprises an air inlet channel 10 and an air outlet channel 11. Both channels 10, 11 extend horizontally through the module 5 and continue as vertical pipes 10a and 11a towards the ground surface G, as disclosed in FIG. 1.

[0058] As shown in FIG. 3, the bio module 5 is arranged in a bio bed assembly 12 with the discharge pipe 6 embedded in a layer of gravel 13. Between the gravel layer 13 and the module 5, a sand layer 14 is provided. The sand 14 and gravel 13 layers permit further purification of the water on its way towards the discharge pipe 6.

[0059] On top of the sand layer 14, a distribution plate 14a is provided. The distribution plate 14a distributes the waste water flowing out of the module 5 before it flows downwards into the sand layer 14 and further down into the gravel 13.

[0060] In FIG. 4, a portion of a carrier plate 7 is shown. The plate 7 comprises innumerable filaments 15 of e.g. thermoplastic polymer, which may be thermoset to obtain the plate-like shape. Preferably, the filaments 15 are irregularly twisted together which forms innumerable interspaces 16 between the filaments 15. Furthermore, it is preferred to use filaments 15 which are about 2-3 mm in diameter and which has a matte and rough, or rugged, surface. The plates 7 are preferably about 40 mm thick in this embodiment. In other embodiments, the diameter of the filaments 15 and the thickness of the plates 7 may vary. The rugged filaments 15 provide suitable surfaces for microbial growth. The twisting and meandering shape of the filaments 15 provide a very large attachment area for microbes within each carrier plate 7. As an example, a module 5 with a size of 1105525 cm has 82 m.sup.2 of attachment surface.

[0061] In some embodiments, a plastic net 17 is inserted between a first carrier plate 7 and a neighbouring sheet 8 of geo textile, in order for the first carrier plate 7 to press the sheet 8 towards a neighbouring carrier plate 7 in an even way. One layer of such an assembly, comprising a carrier plate 7, a geo textile sheet 8 and a net 17, is shown in FIG. 5.

[0062] In the following, the water purification process of the system 1 will be described in connection with FIGS. 1 and 6. In use, the filaments 15 of the carrier plates 7 and the geo textile sheets 8 are covered by microbial growth, which decomposes BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand).

[0063] Water or sewage to be treated or purified flows from a household, or other facility, to the sludge separator 2 via the inlet 3. In this septic tank or sludge separator 2, particle impurities are removed from the water. The decomposition of particle impurities requires a lot of oxygen. Therefore, it is advantageous to removeat least to a great extentthese impurities already in the sludge separator 2. Thereafter, the water flows from the separator 2, via the outlet 4, into the purification module 5, via the distribution pipe 9. From the distribution pipe 9, the water trickles through the perforations 18a, 18b and into the sandwich structure of carrier plates 7. Since the carrier plates 7 comprise the interspaces 16, the water is able to pass through them. The carrier plates 7 are perfused by the waste water flowing through the module 5 in the way shown by arrows in FIG. 6.

[0064] Since the textile sheets 8 are covered by microbial growth, they are semi-permeable to water. Therefore, the water will partly pool on top of and flow along each sheet 8, and thus flow through the carrier plate 7 located above each sheet 8. This is marked by solid, black arrows in FIG. 6. However, some water will trickle through the sheets 8, which is marked by droplets 19. Thus, the water flows slowly, mainly back and forth through each layer of carrier plates 7, and partially through the sheets 8 of the module 5, allowing the bacteria to reduce the impurities (COD and BOD) carried therein. In an embodiment shown in FIG. 5 including the net 17 which presses the geo textile 8 towards the plate 7, the water pools more evenly on top of the geo textile 8, and therefore a more even bio skin production is promoted.

[0065] When the water reaches the bottom level of the module 5, it trickles out onto the distribution plate 14a and into the sand layer 14, and thereafter through the gravel layer 13, and finally through the discharge pipe 6.

[0066] Incoming air flows through the air inlet channel 10, effectively providing oxygen to the module 5. The oxygen transportation is shown as white arrows in FIG. 6. I.e. the oxygen is transported from the air inlet channel 10, as well as from the distribution pipe 9, towards the air outlet channel 11. The whole module 5 is thus effectively oxygenated.

[0067] Each level of carrier plates 7 can only receive a certain amount of water. Thus, the water which cannot be taken up by, and pass through the first level, will flush through the first level carrier plate 7 and down to the next level. In this process, old and dead microbial growth will be rinsed away from the carrier plate 7 of the first level and brought with the excess water to the next level of carrier plates 7. A chain reaction arises, in which excess water from each level brings the dead microbial growth towards the outlet of the module 5. Thus, the module 5 is self-cleaning and the risk of clogging due to material build up is reduced. This flushing process is most important for larger assemblies (not shown) with several modules 5 connected to each other, since they are more likely to become clogged. The flushing also occurs to a greater extent in such larger module 5 assemblies since they are exposed to a higher water flow.

[0068] In one embodiment (not shown), two or more modules can be connected to each other. In this case, guide tubes 22 are inserted, approximately 10 cm, into the air channels 10, 11 of a first module 5. An opposite end of the guide tube 22 protrudes approximately 10 cm outside the module 5. The protruding portion of the tube 22 is insertable into the air channels of a second, neighbouring module, and thus the air channels of both modules become aligned, and air can flow through the module assembly. A guide tube 22 is schematically depicted in the air outlet channel 11 in FIG. 2.

[0069] If needed, a compressor 20 or another air supplying device may be connected to the air inlet channel 10, as shown in FIG. 2. This may be suitable in case of high biological load on the module 5, or e.g. when several modules 5 are connected to each other, forming long air channels 10, 11.

[0070] A slightly modified waste water treatment module 5 is illustrated in FIG. 7, in which the elongate distribution pipe 9 on top of the vertically stacked carrier plates 7 is disposed adjacent a lateral side of the module 5. The partitions 8 are slightly different and are placed in another configuration which creates a modified flow of waste water within the module 5 (as is illustrated by the arrows).

[0071] In the above, the waste water treatment bio module 5 has been described in a bio bed implementation, but it is also possible to use the module 5 in an infiltration implementation, or in an enhanced infiltration implementation. In the case of enhanced infiltration implementation, the gravel layer 13 and the discharge pipe 6 are excluded from the assembly. In the case of infiltration implementation, both the sand layer 14 and the gravel layer 13 as well as the discharge pipe 6 are excluded from the assembly. The distribution plate 14a is still used during infiltration.

[0072] It should be appreciated that modifications are feasible. For example, the partitions 8 are not limited to be made of geo textile, alternatively they may comprise open pore plastic foam or other permeable material. Also, the partitions 8 may have different thickness, and the partition 8 and the plastic net 17 may be produced as one unit. The number of carrier elements 7 and partitions 8as well as the inter-related arrangement of these componentscan vary depending on the specific purification demands or design requirements. Different flow patterns can be used in the module 5 as long as the aimed-at waste water treatment is achieved.

[0073] In FIG. 8 a second version of the waste water or sewage water treatment purification system is illustrated. This system 1 comprises a septic tank or a sludge separator 2, herein referred to as a waste water vessel 2, with an inlet 3 for untreated waste water and an outlet 4 for water processed by the waste water vessel 2. The inlet 3 is arranged above a maximum waste water level 2a. The vessel 2 also comprises an air inlet 25 placed above a maximum waste water level 2a in the vessel 2. In addition, the vessel 2 has an optional air outlet 27a also located above the maximum water level 2a.

[0074] For instance, the waste water vessel 2 can be a container of the type described in WO 2000/004972A1 developed by the present inventor. However, also other types of particle separating units and waste water vessels can be used.

[0075] In the second version embodiment, the waste water treatment vessel 2 is situated subsurface beneath a ground level G. A top portion 2b of the waste water vessel 2 protrudes above the ground level G. The waste water vessel 2 can in other embodiments be placed above ground level G (not shown).

[0076] Furthermore, the treatment system 1 comprises a waste water purification apparatus or module 5 in which the waste water is further treated and purified. Various modules 5 can be used in the system 1. In one example, the module 5 provides surface area for the growth and culturing of a bio film. Microbes such as bacteria, suitable for degradation of contaminating particles present in waste water, inhabit the bio film.

[0077] Waste water flows through the bio film inside the bio module 5, and microbes purify the water biologically. The direction of the flow is diverted either with the assistance of gravity or by the design of the module 5 itself. Bio modules of this basic type are illustrated for instance in the Applicant's English-language brochure entitled Sewage plants for single households up to 1000 people (and more) from 2014.

[0078] In the second version embodiment, the waste water treatment module 5 is arranged subsurface beneath the ground level G. The module 5 is covered with soil mass and possibly also by a protective sheet (not shown). For ventilation purposes, the module 5 is equipped with an air inlet channel 10 and an air outlet channel 11. Furthermore, an elongated waste water distribution pipe 9 is arranged on the top of the module 5.

[0079] In addition, the system 1 comprises an air supplying device 20 which in the present embodiment is arranged above ground level G. The air supplying device 20, which herein is mainly referred to as a pump, may be a compressor, a membrane pump, air pump or the like. The air is supplied to the module 5 through a first air conduit 23, herein also referred to as a first air pipe 23, connected between the pump 20 and the air inlet channel 10.

[0080] A second air conduit 24, herein also referred to as the second air pipe 24, is connected between the air outlet channel 11 of the module 5 and the vessel 2. The second air pipe 24 has a first end portion 24a connected to the air outlet channel 11, and a second end portion 24b connected to the air inlet 25 of the vessel 2. In practice, the diameter of the second air pipe 24 is preferably about 50 mm, but other dimensions may be used. In certain situations, the second air pipe 24 may be provided with an external insulation material (not shown). The insulation material serves to keep the temperature within the second air pipe 24 at such level that condensation is prevented.

[0081] The air inlet 25 of the vessel 2 is located above the maximum waste water level 2a. If the air inlet 25 is located beneath the water lever 2a, a higher air pressure would be needed to successfully press the air back into the vessel 2. Since the air outlet channel 11 is placed near the top surface of the module 5 and since the air inlet 25 is arranged above the maximum water level 2a, sediment and filthy water are prevented from entering the second air pipe 24. A waste water pipe 26 is connected between the vessel 2 and the distribution pipe 9 of the module 5.

[0082] In FIG. 9, the second version of the waste water purification system 1 of FIG. 8 is installed adjacent to a house or other facility 28 which is equipped with a ventilation valve 30. A water inlet pipe 3a is connected to the ventilation valve 30 on the facility 28. Optionally, an air outlet 27a and an air pipe 27 of the vessel 2 can also be installed to enhance ventilation. The ventilation valve 30 is not to be limited to be arranged on the roof top of the facility 28, but it could also for instance be placed in a wall of the facility 28. The water inlet pipe 3a is connected between the facility 28 and the water inlet 3 of the vessel 2. Air from the vessel 2 exits the vessel 2 through the water inlet pipe 3a. A lavatory, sink or other sewage or waste water facility 29 within the building, herein referred to the waste water source 29, is connected to the water inlet pipe 3a.

[0083] The operation of the waste water treatment system 1 will now be explained further. Waste water or sewage from the waste water source 29 of the facility 28 first arrives via the inlet pipe 3a and the inlet 3 to the vessel 2 which is advantageous due to its capability to sediment particle impurities from the waste water. The removal of particles already in the vessel 2 enhances the efficiency of the purification in the module 5 and a lower air supply is needed.

[0084] The waste water exits the vessel 2 via the outlet 4 and flows through the pipe 26 into a first end 9a of the elongated distribution pipe 9 of the module 5. From the distribution pipe 9, water perfuses down into the module 5 where it is biologically treated by microbes. Commonly, purified water flows out of the module 5 through a discharge pipe and into layers of pebbles, gravel and sand (not shown).

[0085] Simultaneously, pressurized air is supplied to the module 5 by means of the pump 20. Air will flow through the first air pipe 23 and enter the module 5 via the air inlet channel 10. The air will travel upwards through the module 5 towards the air outlet channel 11 and assist the biological purification of the waste water by providing oxygen to the microbes. In addition, the air serves to maintain the module 5 in a well functioning state, feeding the microbes such as bacteria with oxygen and preventing clogging of internal compartments of the module 5.

[0086] Examples of air supplying devices are a membrane pump, an air pump, a compressor or the like. An approximate amount of air suitable for a facility adjacent to a family house may be 100 liters/minute. However, the distance between the vessel 2 and the module 5 will affect the suitable amount of air needed. The size of the module 5 will also affect the need for a different amount of pressurized air.

[0087] The air is then led back into the waste water vessel 2 through the second air pipe 24 via the air inlet 24a. Since the air inlet 24a is placed above the water level 2a, the procedure of pressing the air back into the vessel 2 is facilitated.

[0088] Finally, air is ventilated out of the vessel 2 through the water inlet pipe 3a and out through the ventilation valve 30. Optionally, air can also be ventilated through an air outlet 27a of the vessel 2, into the air pipe 27. When supplying (pressurized) air to the vessel 2, the pressure in the vessel 2 increases and an overpressure is generated. Said overpressure decreases the risk of foul smell. Due to the overpressure in the vessel 2, the air circulation is increased. This in turn decreases the risk of malodorous air standing still in the ventilation valve 30 and smell from the sewage or waste water is thus prevented. The inlet 3 is arranged above the maximum waste water level 2a of the vessel 2 in order to ensure that the use of the water inlet pipe 3a as an exit for air to escape the vessel 2 becomes effective.

[0089] As stated above, the distance between the module 5 and the vessel 2 will affect the need of a higher or lower air pressure. When the distance between the module 5 and the vessel 2 increases, higher air pressure will be required in order to press the air into the vessel 2 in a satisfactory manner. The system 1 is well functioning when the module 5 and the vessel 2 are spaced about 20 meters, preferably spaced 8-10 meters, and most preferred 3 meters apart from each other.

[0090] The system 1 according to the second version in FIGS. 8-9 is a ventilated system for efficient waste water treatment. The ventilation enhances the biological cleansing of the waste water, makes the cleansing process more efficient and reduces the risk of clogging caused by dead bio film. The system 1 according to the second version also reuses the air supplied to the module 5 by diverting it further to the vessel 2. This creates a system with low risk of foul odor from the vessel 2 and ventilation valves 30 of adjacent facilities 28.

Certain Aspects and Embodiments of the Second Version

[0091] In one aspect, there is provided a ventilated system for waste water treatment 1 comprising a waste water vessel 2, a waste water treatment module 5, an air supplying device 20 connected to an air inlet channel 10 of the module, and an air conduit 24 configured to lead air from an air outlet channel 11 of said module 5 to an air inlet 25 of said vessel 2.

[0092] In one embodiment, the waste water vessel 2 is arranged at least partly below a ground level G.

[0093] The waste water vessel 2 may be a septic tank or a sludge separator.

[0094] The module 5 is preferably configured to receive air through said air inlet channel 10 and to lead said air out of the module 5 through said air outlet channel 11.

[0095] In one embodiment, a first end portion 24a of said air conduit 24 is connected to the air outlet channel 11 of the module, wherein a second end portion 24b of said air conduit 24 is connected to said waste water vessel 2.

[0096] Preferably, the air inlet 25 of the vessel 2 is located above a water level 2a of the vessel 2.

[0097] In one embodiment, the vessel 2 further comprises an air outlet 27a configured to lead air to a ventilation valve 30.

[0098] The module 5 is preferably arranged in a bio bed.

[0099] In one embodiment, the air supplying device 20 is one of a compressor, a membrane pump or an air pump.

[0100] In a second aspect, there is provided a method for ventilating a waste water treatment module 5 of said system 1. The method comprises the steps of supplying air to the module 5, and leading the air through said air conduit 24, such that said air is diverted from said module 5 into said waste water vessel 2.

[0101] In one embodiment, the air is supplied to generate an overpressure in the vessel 2, such that ventilation of said vessel 2 is eased.

[0102] In a third aspect there is provided a kit for providing ventilation to a waste water treatment system 1 including a waste water treatment module 5 and a waste water vessel 2. The kit comprises an air supplying device 20 and an air conduit 24 configured to feed air from the waste water treatment module 5 to the waste water vessel 2.

[0103] In a fourth aspect the use of an air conduit in a waste water treatment system 1 is provided, for connecting a waste water treatment module 5 to a waste water vessel 2 included in said system 1, such that air is reused.

[0104] Finally, it should be mentioned that the inventive concept is not limited to the embodiments described herein, and many modifications are feasible within the scope of the appended claims. For instance, several modules, vessels and pumps may be combined into a larger water treatment installation, where each module is connected to one vessel or several modules are connected to the same vessel or several vessels are connected to a lower number of modules. The pump may be connected to one or more modules. Furthermore, the specific design of the conduits between the arrangements included in the system may vary.