FIELD OF THE INVENTION

The invention relates to an apparatus and method for treatment of air by algae.

BACKGROUND OF THE INVENTION

Algae have been found as promising candidates for air and wastewater treatment. It is known that they feed on CO2, and moreover are able to neutralize other 'harmful' gases, eg methane ammonium and sulphates, chlorides, etc. which makes them very interesting for agricultural and industrial purifier purposes.

Since algae form living matter, it has been found a challenge to provide an environment wherein treatment can be performed optimally. In addition it is found a challenge provides an optimal interaction with the air and the algae. For these problems, the present invention aims to provide a solution. US20080274494 discloses a production facility for removing CO2 from air using algae using transparent channels. To prevent contamination, this disclosure contemplates inter alia contemplates to use a 'sterile suspension' which is in practice extremely difficult to produce. Furthermore, the efficacy of the system suspension is limited.

In WO9324205 a biofiltration system is shown of gases, comprising a column wherein a perforated perspex plate supports a biofilter bed. The biofilter bed is sprayed with nutrients and micro-organisms. The system suffers from a substantial back pressure problems due to the nature of the biofilter bed and has limited interaction with the micro-organisms, which necessitates an increase in the retention time of the gas in the biofilter bed further adding to the problem. The invention aims to provide a solution that better confronts these issues.

SUMMARY OF THE INVENTION

To this end, the invention pertains to a method of treatment of a gas mixture comprising the steps of directing said gas mixture having a principal flow direction into a treatment chamber comprising a basin for containing an algae culture; providing a spray of droplets by atomizing a slurry of algae wherein the droplet spray is directed with at least a component against the principal flow direction to produce a saturated gas mixture; wherein larger droplets parts are received in the basin; and directing a remaining saturated gas flow through an exhaust structure of said treatment chamber; said exhaust structure providing an interaction surface for an algae culture with the saturated gas flow; said exhaust structure is punctured to keep the algae free from liquid and at the same time function as gas exhaust.

In another aspect, the invention pertains to a treatment chamber for treatment of a gas mixture according to any of the previous claims; comprising a gas flow pump for directing said gas mixture into the chamber to have a principal flow direction; a basin for containing an algae culture;

one or more spray heads and a pump for atomizing a slurry of algae from the basin into a spray of droplets, wherein the spray heads are oriented to have the droplet spray directed with at least a component against the principal direction to produce a saturated gas mixture wherein larger droplets parts are recycled in the basin; an exhaust structure in the form of a stack of multiple racks, that support the algae in coagulated form thereby providing an interaction surface for an algae culture with the saturated gas flow; the saturated gas flow further entering the exhaust structure comprising racks with an open drain structure through which the gas flow is diverted, said open drain structure keeping the algae free from liquid and at the same time function as gas exhaust, said racks further comprising a shielding structure for shielding an underlying rack against flow of liquid thereby diverting the liquid away from the underlying rack into the basin and at the same time diverting the gas flow through the open drain structure; and a drying system arranged downstream of the exhaust structure, to dry the gas exiting the exhaust structure; and removing surplus liquid back into the basin. The remaining air is practically dry, odourless and many of the harmful gases are removed through optimal contact with the algae culture.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 describes in schematic detail a first embodiment; Figure 2 shows a second embodiment in schematic detail; Figure 3 shows another embodiment in some schematic detail;

Figure 4 shows a stacked exhaust structure as part of the embodiments of Figure 1;

Figure 5 shows a schematic front side of the stacked exhaust structure.

Figure 6 shows a schematic side view of a filter and brush system.

Figure 7 shows a filter system.

DETAILED DESCRIPTION OF EMBODIMENTS

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs as read in the context of the description and drawings. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. In some instances, detailed descriptions of well-known devices and methods may be omitted so as not to obscure the description of the present systems and methods. The term "and/or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms

"comprises" and/or "comprising" specify the presence of stated features but do not preclude the presence or addition of one or more other features. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control.

Throughout the application, any means for carrying out the disclosed methods, in particular, as further clarified below: air transporting means, air cleansing means that are known to the skilled person and may differ in form and structure to arrive at the same function; i.e. the function is physically implemented in constituting elements such nozzles, rotors fans etc. It is to be understood that air, is denoted in its usual meaning and irrespective of specific constituent. Furthermore, air may also be a specific gas mixture that is an exhaust product from a chemical process. In this respect, air is to be understood as gaseous mixture can be converted or filtered by algae and may for example be ambient air further comprising with one or more constituents, e.g. C02, methane ammonium and

sulphates, chlorides, nitrates and phosphates. Furthermore, 'saturated' air is used as containing a maximal or close to maximal humidity component, in the form of a vapour or fine mist, e.g. with mist particles smaller than 500 micron, but preferably much smaller to reduce liquid forming near the 'dry culture', e.g. in a range smaller than 50 micron. In this respect, further, the treatment chamber cooperates with living matter, but as such functions substantially independently thereof. That is, the apparatus and method can utilize any algae of suitable substance, to be further exemplified in the below. In the text is further mentioned a 'dry culture' of algae. In this respect, dry is to be understood in the sense of dry, but alive, where a normal humidity is maintained to keep the algae alive. This is e.g. possible by drip feeding or intermittent spraying, in order to keep the culture sufficiently wet, but without unduly trapping moisturized air by saturated air in a liquid phase.

The invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The description of the exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the drawings, the size and relative sizes of systems, components, layers, and regions may be exaggerated for clarity. Embodiments are described with reference to schematic illustrations of possibly idealized and/or intermediate structures of the invention.

Figure 1 shows an embodiment utilizing the operating principle of the inventive concept. Treatment chamber 100 is provided for treatment of a gas mixture A directed by a gas flow pump (not shown). The pump may be provided in, prior or after the treatment chamber to have a principal flow direction into the chamber. In A, polluted air to be filtered optionally enters a first washing compartment B, wherein the air is washed in a conventional fashion, using sprays and optionally one or more pumps M and a water basin H. In this stage, pollutants, i.e. primarily particles of larger size, are filtered and washed out of the supplied air and/or will be deposited on (separating) walls C. Pollution can be filtered out and transported away from filter bath H. Unless the constituent gases dissolve in the water, they are further transported as a cleansed air mixture into an algae treatment chamber that is designed according to the invention. In this treatment chamber 100, an array of micro spraying nozzles D vaporizes an algae slurry that is suitably diluted. That is in a basin K a suitable mixture of algae is kept, that is fed by the constituent gases (notably: C02), water and light, which may be of artificial nature. The micro spraying nozzles are able to vaporize the algae in microdroplets, etc. of a dimension smaller than 500 micron but preferably smaller than 200 micron and having a constituent particles of e.g. 5-50 micron. The nozzles function as an atomizer; i.e. a large range of droplets with algae

constituents are formed. The constituent is such that the air is brought maximally in contact with the mist which is of saturated or largely saturated constituency. Figure 7 provides more detail on a filter structure L, that provides algae of a suitable dimension in order not to clog the nozzles. A drying system is provided in the form of centrifugal separator X. This separator separates moist particles with possible algae substance from the air, and separated liquid is drained to the basin K.

Preferably, the nozzles are directed under an angle, more preferably against the air flow, so that good intermixing occurs and only the smallest mist droplets are carried into the next compartment E.

Accordingly, one or more spray heads are provided and a pump for atomizing a slurry of algae from the basin into a spray of droplets smaller than 50 micron, wherein the spray heads are oriented to have the droplet spray directed with at least a component against the principal direction to produce a saturated gas mixture; wherein larger droplets parts are received in the basin. In another aspect of the invention compartment E is a closed confinement, where the flowing air exits via punctured transparent racks or plates, that carry a semi dry algae culture. I.e. the algae are kept alive by feeding them via the moisturized air, and preferably without or only minimal additional water supply, in order to maximize the interaction of the saturated air with algae. Importantly the moisturized air is brought in direct contact with the algae, as in contrast to a liquid slurry form. The depicted exhaust structure E comprises a stack of multiple racks, that support the algae in coagulated form thereby providing an interaction surface for an algae culture with the saturated gas flow. The racks have an open drain structure through which the gas flow Q is diverted. The open drain structure keeps the algae free from liquid and at the same time function as gas exhaust. The racks further comprising a shielding structure (see Fig 3) for shielding an underlying rack against flow of liquid thereby diverting the liquid away from the underlying rack into the basin and at the same time diverting the gas flow through the open drain structure. At X a drying system is arranged downstream of the exhaust structure, to dry the gas exiting the exhaust structure; and removing surplus liquid back into the basin K.

According to a further aspect, in compartment E, the punctured transparent racks are formed as light guides for illuminating the algae culture. The light guides may be provided in the form of a grid of (micro) grooves, where light couples into the algae culture.

Typical flow speeds may vary from 0,01-1 m/s where an optimum is selected in order to optimize the interaction time of the air with the algae culture. Additionally, several compartments E may be coupled in parallel or in series.

Importantly, the air exits preferably largely via the through holes, in order to have the air flow passing through the algae as much as possible. In this respect, see Figure 3, the racks 35 are provided with shields 33, that shield the punctured plates against flowing liquid. In addition, preferably, the shields are formed to direct the air flow through the culture as much as possible. The air guides are formed of plates forming a wedge with the punctured culture plates.

The punctured racks are preferably also coupled to light guides, i.e. structures that couple the nurturing light into the culture racks. Nurturing light may be provided by natural sunlight, coupled via light guides, but may also be provided by artificial light sources F, e.g. LED lights, coupled directly into the culture racks.

Figure 2 shows an example of the operating principle of a slurry jet that is splashed into atomized droplets e.g. by fast rotation. This may be done by swirler spray head 200 that provides an optimal way of forming a mist of a slurry of algae. To this end, the slurry needs to be atomized, which may be effectively done by means of spray head 200 comprising a central bore 25 and a rotatable spinner member 26 comprised therein. The spray head has a cap 27 having an exit slot 28 in fluid communication with the central bore 25. The spinner has spiraling grooves 29 that swirl the slurry through slots 28 in atomized form. The slots are relatively wide to prevent clogging, but by high pressure and fast rotation, micro droplets of algae are formed.

Figure 3 shows in more detail exhaust structure 300 and their function in respect to the algae. The exhaust structure may be formed as a stack of culture racks 35, formed from a glass like plastic material, such as PET, PEN, PMMA or the like, which is machinable, that may be

provisioned in a substantially horizontal manner. The racks 35 may be punctured in a fine mesh of through holes, e.g. holes of about 1-5 mm in diameter, keeping in mind that smaller holes will clog and larger holes will provide flow speeds that are un desired, to keep the residence time of the air optimal in the dry culture. Accordingly an interaction surface is formed for an algae culture with the saturated gas flow. The exhaust structure is punctured to keep the algae free from liquid and at the same time functions as gas exhaust. Shield structures 33 are provided shielding the exhaust structure against flowing liquid and additionally preferably for at the same time guiding the saturated gas flow through the exhaust structure in such a way that the flux through the rack 35 is spread over the entire rack, optimally in a substantially homogenous way. This can be provided e.g. by wedged (optionally curved) plates 33 provisioned under an angle in a range of 10-40 degrees relative to said racks 35. The wedged guide plate is coupled to said rack in an oblique fashion, the wedged guide plates thereby diverting liquid from the open drain structure away from an underlying rack, into the basin.

Figure 4 shows how a dry culture is formed of larger coagulated pieces of algae, e.g of 5 - 30 mm. These pieces can be harvested from a separate culturing basin Z, wherein algae in a micro slurry S, of e.g. 5 cm deep coagulate on the surface of the basin. Nurturing light sources Y e.g. 600 Watt lamps held provided shortly above the basin provide sufficient growth conditions for a e.g. 60x60 cm area per lamp together with growth additives supplied in the basin. Harvesting can be done in about every two weeks. By stirring and circulating the algae, the nurturing light is able to reach all the organisms so that optimal growth is obtained. Thus, the coagulated form is a solid non fluid mass of algae chunks similar to weeds found in seas. The coagulated chunks are harvested in solid chunks from the basin Z; dewatered and subsequently put on the racks 35 where they are put into effect for for air treatment.

Figure 5 furthermore shows a preferred form, wherein the effective area of the algae is maximal, by stacking plurality of the structures depicted in Figure 3. Accordingly, a layered structure of shields and culture racks is provided, that can be provisioned relatively close to each other, e.g. in a range of 5-15 cm, with a plate area that can range from several cm2 to m2, depending on the size of the treatment chamber. Since the treated air exits through the punctured plates, a clogging problem can be substantially prevented by homogenizing the gas flow and keeping sufficient flow. As schematically indicated, by the stack structure 400 of racks 35, the wedged shields 33 simultaneously function as drains that receive liquid from the punctured plates 35 above to keep the interaction surface with the algae free from liquid phase, that is drained and captured in basin 45.

Figure 6 shows a front view of the treatment chamber, wherein it is shown how an exhaust structure is provided with growth lamps 500, that illuminate the culture from aside. In an embodiment, the punctured racks are illuminated by artificial light that is directed via a transparent container wall surface into the algae culture. To this ends LEDs may be coupled directly to the sides of racks 35.

Figure 7 shows filter system L, that is a drum of fine slits with in obhque direction relative to a length axis. A brush system A rotates around the drum D by means e.g. of a water turbine C that drives the brushes B along the outer wall of the slitted drum D. In this way, only fine algae smaller than e.g. 0.1 mm. are pumped to the swirler spray head 200 and clogging is prevented.

The disclosed embodiments are only depicted by functional elements, i.e. most of the powered optics used for imaging has been left out. Practical embodiments may therefor be enhanced by functional features represented by optical elements having the same functional effects.