Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
  • C02F3/12—Activated sludge processes
  • C02F3/1236—Particular type of activated sludge installations
  • C02F3/1242—Small compact installations for use in homes, apartment blocks, hotels or the like
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
  • C02F3/04—Aerobic processes using trickle filters
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

• the present invention concerns compact devices for the purification of wastewater from single homes and small agglomerations, often referred to as miniature water purification plants.
• WO 93/02015 discloses a compact device for the treatment of sewage-effluent, wherein the effluent within one joint, closed circuit is exposed to a filtering process, together with both an aerobic and an anaerobic treatment.
• a first sludge filter and an aerobic zone consisting of filter material contained in sacks, are situated above the anaerobic zone forming an extra sludge filtering zone.
• the construction is not optimised for simplifying maintenance and the change of filter material remains labour consuming. Further, the construction of the device according to WO 93/02015 does not allow easy and unhindered sludge removal from the anaerobic zone.
• the present invention therefore sets out to solve the problems indicated above and to make available a compact, simple and reliable plant for water purification and in particular a plant comprising means for mechanical, biological and, as a preferred embodiment, also chemical purification.
• the plant according to the present invention should be possible to use in combination with a septic tank and similar existing installations or, according to a preferred embodiment of the invention, completely replace the traditional septic tanks.
• a complete miniaturised water purification plant comprising means for mechanical purification or sludge separation, biological purification and, in preferred embodiments, also chemical purification.
• a biological purification step surrounded by the means for mechanical treatment and, optionally also means for chemical treatment, a compact and reliable solution is achieved. It is thereby guaranteed that the microorganisms participating in the biological purification step are kept at an even temperature suitable for their function and survival.
• the plant according to the present invention also allows the regular taking of samples and control of the quality of the purified water.
• the filter material is easily changed, adapted for different purification needs, supplemented etc. Additionally, part of the used filter material can be composted or used in land fill applications. Further advantages of the present invention will become evident from a closer study of the description and drawings.
• Fig. 1 shows a schematic view from above, showing an embodiment having a central biological step, surrounded by means for mechanical treatment;
• Fig. 2 shows schematically an embodiment having a central biological step, surrounded by means for mechanical and chemical treatment
• Fig. 3 shows a schematic cross section of a miniaturised water purification plant according to the invention
• Fig. 4 shows schematically the construction of an exchangeable cassette for use in a plant according to the invention.
• anobic is used to define conditions which support the proliferation of organisms requiring molecular oxygen as well as organisms able to grow either in the presence or in the absence of molecular oxygen, including organisms that require a low partial pressure of oxygen.
• fibrous is used to denote different materials that substantially consist of elongate components, either entangled or separate, such as fibres, threads and the like.
• fibrous materials include cellulose fibres, for example in the form of wood chips, different fractions of peat, mineral wool and the like.
• particle is used to denote materials that substantially consist of separate particles, such as different fractions of sand and gravel, ceramic fillers, crushed concrete or crushed bricks, expanded clay products etc.
• mechanical purification is meant to include means and process steps for the removal of components in the wastewater based on their size, specific weight, sedimentation properties etc. Sedimentation is one example of mechanical purification.
• chemical purification is meant to include means and process steps for the removal of components in the wastewater based on their chemical behaviour, for example by the addition of coagulants, flocculation agents etc.
• a chemical purification step is preferably followed by a sedimentation step.
• the term “biological purification” is meant to include means and process steps for the microbial digestion of nutrients contained in the wastewater.
• the miniaturised water purification plant according to the invention is characterised in that it comprises at least one sedimentation step and one aerobic, biological purification step within one container, through which the water to be purified flows by gravity.
• the sewage water enters the purification plant 1 through an inlet 2 and enters a first sedimentation step 4, from which the overflow is led to a second sedimentation step 5 and further to a third sedimentation step 6.
• the overflow from step 6 is then led into the biological reactor 7.
• Purified water is released into the environment through outlet 8.
• the sedimentation steps surround the aerobic, biological purification step. This arrangement helps to keep the central biological step at temperatures suitable for the proliferation of the microbes providing for the aerobic digestion of the organic components in the wastewater.
• a chemical purification step is added by including an elongate vessel around the periphery of the container (not shown) or as another concentric compartment 3 of the purification plant 1. Suitable chemicals are then added to the in-flow of sewage, mixed with and reacting with the components of the sewage during a duration determined by the length of the flow path in said vessel.
• a long flow path is achieved.
• Fig. 2 shows a schematic cross section of a purification plant 1 having an inlet 2. and sedimentation steps 4 and 5, the third step not shown.
• the central, biological purification step 7 has an outlet 8 and is closed with a lid or cover 9.
• a conduit 12 leads air to a discontinuity in the biological reactor.
• Each sedimentation step 4 and 5 has a manhole 10 and 1 1 for removing sludge. The corresponding manhole for the third sedimentation step is not shown.
• the plant has means for facilitating lifting, for example lifting ears 13 (only one is shown) for lifting the plant, securing it during transport and finally, for anchoring it upon installation.
• the construction of the miniaturised water purification plant provides direct access to all the compartments of the plant.
• sludge can be removed from the sedimentation steps.
• the filter material in the centrally located space 7 for the biological step can easily be inspected and replaced.
• the biological step is constructed as a filter cassette, as described further in the description, the used cassette is easily removed vertically and a new inserted quickly and with minimal disturbance of the functioning of the plant.
• the space 7 reserved for the biological purification step can be filled with filter material to obtain a filter which functions according to the following principles: the sewage is introduced near the top of space 7, through means for spreading the liquid evenly over the surface of a underlying - first filter, which can consist of a homogenous filter bed or two or more layers of different filter materials, under which
• a first discontinuity or gap provides aeration of the liquid, precipitating through the first filter, before reaching an underlying
• - second filter which can consist of a homogenous filter bed or two or more layers of different filter materials, under which a second discontinuity or gap provides aeration and prevents over-saturation of the second filter, whereupon
• the purified liquid exits the biological purification step through an outlet.
• the biological purification step can be constructed by assembling filter elements, supporting structures and the like, directly into the space 7, provided that the above principles are followed.
• the two discontinuities or gaps have been found to be of considerable importance not only for aeration purposes but also for preventing the filters from becoming over-saturated with liquid.
• the above principles can be followed even if the loose filter material is loaded into the space 7, provided that suitable spacers and/or supporting structures are used. It is also possible to enclose the different components in building blocks of a water permeable material, having a cylindrical or other shape, fitting into the space 7.
• the biological purification step is arranged in an exchangeable filter cassette, such as the cassette 14 shown in Fig. 4.
• This filter cassette comprises at least one filter bed, into which the clarified sewage is infiltrated. When infiltrated with sewage, this filter bed will quickly become colonised by a flora of microbes decomposing the nutrients in the sewage.
• the biological step consists of at least one filter cassette 14 having an upper and a lower filter bed, separated by a discontinuity or gap 22 for allowing air to enter and a similar discontinuity or gap 25 below said lower filter bed, in order to keep the lowest part of the filter constantly above the highest water level at the bottom of the biological step.
• Fig. 4 shows a cross section of a filter cassette 14 according to a preferred embodiment of the invention.
• the wastewater having passed through the sedimentation steps and - optionally - a chemical treatment step, enters the biological purification step via an inlet 15, connected to a tube or grid of tubes 16 having holes for evenly distributing the clarified wastewater over the filter beds.
• the wastewater first enters an upper filter bed, which here consists of a first layer 17 of a fibrous filter material, for example mineral wool.
• Mineral wool has shown to be very suitable, as it offers a large area to be colonised by bacteria digesting the nutrients in the wastewater.
• a second layer of a particulate filter material for example expanded clay granules, such as suitable products from the Leca® product range, Filtralite® granules, sand, gravel or the like, is situated.
• This layer is preferably supported on a perforated support 19, for example a sieve.
• This third layer is preferably a fibrous filter, for example mineral wool.
• the second or lower filter bed 23 consists of a particulate filter material, for example sand, gravel or expanded clay granules, such as suitable products from the Leca® product range, Filtralite® etc.
• the composition of the particulate material is chosen depending on the quality of the wastewater to be purified and the required degree of purification. By selection of particular minerals, this second filter bed can be used to remove specific components in the wastewater. for example to lower the phosphorus content of the wastewater.
• the second or lower filter bed 23 rests on a perforated support structure 25, a certain distance above the bottom of the water purification plant. This distance is 3 to 5 cm or more, but at least enough to prevent the filter bed 23 from being in contact with water on the bottom of the purification plant.
• the purified water exits the plant via outlet 8.
• outlet 8 arrangements for the collection of samples can be made. Samples taken at this point give a very accurate picture of the degree of purification achieved, as no further purification, such as infiltration in underground sand filters etc. is required.
• the cassette 14 thus consists of at least one upper filter bed 18, and one lower filter bed 23, suspended above the bottom of the plant, thus forming a second discontinuity or gap 25.
• the second gap 25 helps to lead air to the lower filter bed, but more importantly, helps to prevent over-saturation or "ponding" in the filters.
• the biological purification step comprises a smell absorbing filter 26, resting on a support structure 27 above the inlet 15.
• the smell absorbing filter 26 preferably consists of peat enclosed in flat, cylinder shaped pillows of perforated material, a mesh of synthetic or organic fibres, a wire cloth or the like.
• the smell absorbing filter 26 may rest on a perforated structure 27 simplifying the removal of this filter alone, to allow inspection of the upper filter bed.
• the upper filter bed is preferably covered by a pre-filter (not shown), for example a mesh or filter cloth, protecting the underlying filter bed from particulate matter which can pass through the sedimentation steps at high flow. This pre- filter can then be changed at intervals shorter that the intervals for changing the entire filter cassette 14.
• the smell absorbing filter In colder climates, the smell absorbing filter has a dual function. On the one hand, it absorbs and neutralises smells emanating from the wastewater and the microbiological digestion of the nutrients. On the other hand, it provides insulation of the bioreactor and helps to keep it a temperature, suitable for the functioning and proliferation of the microbes.
• the fibrous filter material in the filter bed or beds 17 an 20 is chosen among the following: mineral wool, cellulose, wood chips, bark, peat etc. It is preferred that the filter material is enclosed in compartments with perforated or otherwise permeable delimiting structures.
• the fibrous filter material is preferably chosen among organic filter materials, suitable for degradation through composting.
• mineral wool has proven to be a very suitable filter material and in particulate blocks of mineral wool manufactured with a press force of 80 to 100 kg.
• the entire biologic purification step is delivered as an exchangeable component or cassette 14, in other words a bioreactor.
• a bioreactor which can be easily inserted in and removed from the space 7 in the miniaturised water purification plant 1.
• This is the preferred embodiment, comprising the possibility of making available different bioreactors having differing filter design and filter material, depending on the intended use and purification requirements.
• This also gives the possibility of "upgrading" the water purification plant when the quality of the incoming wastewater or the purification requirements change. This upgrading can be performed without any changes to the structure of the plant, by simply removing the cassette and replacing it with another.
• Such cassettes can be manufactured from a series of basket-like supporting structures, enclosed in a cylindrical structure.
• said cassette has loops or other means, facilitating its lifting when transporting, removing or installing a cassette.
• the cassette has means for guiding the cassette into right position in the space 7. These means are preferably constituted by a longitudinal groove, corresponding to a vertical ridge along the inner surface of the space 7 of the miniaturised plant 1, guiding the cassette into right position with respect to the inlet 15 and the air-duct 12.
• the cassette can have a longitudinal ridge or ridges, fitting into one or several vertical grooves in the walls of the space 7.
• the bioreactor consists of interchangeable elements, which can be combined to a bioreactor having the required characteristics. It is also conceived, that the bioreactor in itself can function as a purification plant for less contaminated waste water or as a final purification step for water leaving a traditional septic tank. In that case, a suitable outer container having an inlet, corresponding to the inlet 15, and an outlet, corresponding to the outlet 8, both of Fig. 4, is connected to the existing septic tank. A bioreactor according to the invention is then assembled in this container from elements or installed as a cassette, such as the cassette 14 in Fig. 4.
• the aerobic bioreactor according to the invention is characterised in that it comprises at least one filter bed with an underlying discontinuity or gap for allowing the inflow of air.
• the bioreactor consists of an upper and a lower filtration bed. separated by a discontinuity between the two filter beds and having an air-inlet, connected to the outside air.

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• Life Sciences & Earth Sciences (AREA)
• Biodiversity & Conservation Biology (AREA)
• Microbiology (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Biological Treatment Of Waste Water (AREA)

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• 2000
  • 2000-05-05 WO PCT/SE2000/000887 patent/WO2001002307A1/en not_active Application Discontinuation
  • 2000-05-05 AU AU46373/00A patent/AU4637300A/en not_active Abandoned
  • 2000-05-05 FI FI20000203U patent/FI4825U1/fi active
  • 2000-05-05 EP EP20000928086 patent/EP1204605A1/en not_active Withdrawn

Non-Patent Citations (1)

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