WO2016072935A1

WO2016072935A1 - Composite bio-granule for a planting medium

Info

Publication number: WO2016072935A1
Application number: PCT/SG2015/050427
Authority: WO
Inventors: Jian Chu; Yuan Soon LUM
Original assignee: Nanyang Technological University
Priority date: 2014-11-04
Filing date: 2015-11-03
Publication date: 2016-05-12
Also published as: SG11201703567YA

Abstract

A composite bio-granule for a planting medium, the composite bio-granule comprising: a body formed from a mixture of marine clay, pumice, activated carbon and a binding agent; and a plurality of interconnected holes in the body, each hole extending from an exterior surface of the body into a core of the body.

Description

COMPOSITE BIO-GRANULE FOR A PLANTING MEDIUM

FIELD OF INVENTION

The present invention relates to a composite bio-granule for a planting medium and a composite bio-granule planting medium with greater efficiency in neutralizing pollutants in air or water.

BACKGROUND

Conventional manufactured types of artificial planting media typically comprise spherical solid bio-granules. The sole purpose of these conventional bio-granules is for stabilizing the plants in pots for indoor usage. Air or water seep through such media very quickly and there is little retention time or surface area for polluted air or water to be retained long enough for beneficial bacteria to process pollutants efficiently via phytoremediation. SUMMARY

A high efficiency composite bio-granule for a planting medium is disclosed that extends the path of flow, increases surface area for beneficial bacteria to colonize and propagate, and provides longer retention time for the beneficial bacteria to digest pollutants effectively via the phytoremediation process.

According to a first aspect, there is provided a composite bio-granule for a planting medium, the composite bio-granule comprising: a body formed from a mixture of marine clay, pumice, activated carbon and a binding agent; and a plurality of interconnected holes in the body, each hole extending from an exterior surface of the body into a core of the body.

Each hole may be radially provided such that the plurality of interconnected holes intersect at a geometric centre of the composite bio-granule.

Diameter of each of the plurality of interconnected holes may increase towards a geometric centre of the composite bio-granule.

The plurality of interconnected holes may be equidistantly provided on the exterior surface of the composite bio-granule. Internal walls of the plurality of interconnected holes may be configured to have increased total surface area for increased bacterial colonization. The increased total surface area may be formed by providing grooves on the surface of the internal walls.

Ratio of the marine clay : pumice : binding agent : activated carbon may be 3 : 1 : 0.5 : 0.5.

According to a second aspect, there is provided a planting medium comprising a plurality of the composite bio-granule of the first aspect.

DESCRIPTION OF FIGURES

In order that the present invention may be fully understood and readily put into practical effect, there shall now be described by way of non-limitative example only preferred embodiments of the present invention, the description being with reference to the accompanying illustrative figures. Fig. 1 is a perspective view of a composite bio-granule for a planting medium.

Fig. 2 is a cut-away perspective view of an interior of the composite bio-granule of Fig. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS

Exemplary embodiments of the composite bio-granule 10 for a planting medium will be described with reference to Figs. 1 and 2 in which the same reference numerals are used to denote the same or similar parts.

The composite bio-granule 10 comprises a body 15 formed from a mixture of marine clay and pumice. A plurality of the composite bio-granule 10 is used together as a planting medium. To form each composite bio-granule 10, marine clay and pumice are each pulverized into fine powder form and mixed together to form a mixture. Marine clay and pumice are used as they are natural materials and available in abundance. Activated carbon is added to the mixture for the purpose of removing odor. A binding agent is added to the mixture to bond the mixture strongly, such as via microbial-induced carbonate precipitation. An example of a suitable binding agent is a biocement where the binding agency precipitated through microbial processes is used to cement the ingredients together.

In one embodiment, composition of the composite bio-granule 10 comprises a ratio of 3 parts marine clay : 1 part pumice : 0.5 parts binding agent : 0.5 parts activated carbon. The mixture of pulverized composite materials with activated carbon and binding agent are then injected or poured into moulds of a specific design to form the composite bio-granules 10. Using a biocement as the binding agent, no thermal processes or external forming pressures are required as cementation is via the natural process of crystallisation by naturally present bacteria. A holding time of two to three days allows the mixture to sufficiently bond and form the composite bio-granule 10.

As can be seen in Figs. 1 and 2, the composite bio-granule 10 is generally spherical in shape, with a diameter ranging from 15mm to 40mm. The composite bio-granule 10 comprises a plurality of interconnected holes 20 in the body 15 that each extend from an exterior surface 30 of the body 15 into a core 50 of the body 15. In the preferred embodiment, the plurality of interconnected holes 20 are equidistantly provided in the composite bio- granule. Each hole 20 is preferably radially provided such that the plurality of interconnected holes 20 intersect at a geometric centre X at the core 50 of the composite bio-granule 10. Thus, two diametrically opposite interconnected holes 21 , 22 would intersect to form a single diametric through hole in the composite bio-granule 10, such that six interconnected holes 20 may form three centrally intersecting diametric through holes in the composite bio-granule 10.

The interconnected holes 20 allow polluted air or water to pass through the composite bio- granule 10 and provide an ideal habitat for beneficial bacteria to propagate. The interconnected holes 20 also provide greater surface area for greater contact of air or water with bacteria colonized therein. The internal wall 60 of each hole 20 is preferably grooved, as shown in Fig. 2, for increased total surface area available for colonization and propagation of beneficial bacteria. The larger surface area is also able to accommodate larger counts of bacteria and thereby provide higher efficiency in processing the pollutants that are in the air or water that pass through the composite bio-granule 20.

In a preferred embodiment, each hole 20 is slightly bulged as it gets into the central core, i.e., the diameter of each hole 20 increases towards the geometric centre X of the composite bio- granule 10. The bulge shape or increased hole diameter at the geometric centre X provides reduces pressure at the inner core of the composite bio-granule 10, and thus enables air and water to be retained for a longer period of time in the composite bio-granule 10. The longer duration of retention allows bacteria colonies in the composite bio-granule 10 to have more time to process pollutants in the retained air or water, thereby increasing efficiency of a planting medium comprising a plurality of the composite bio-granule 10 in neutralizing pollutants. Whilst there have been described in the foregoing description preferred embodiments of the present invention, it will be understood by those skilled in the technology concerned that many variations or modifications in details of design or construction may be made without departing from the present invention. For example, while a composite bio-granule having six interconnected holes has been described, it is envisaged that other numbers of interconnected holes may be provided in the composite bio-granule. While the composite bio-granule has been described as being generally spherical, the composite bio-granule may be configured with other shapes such as cube, tetrahedron, and other polyhedrons. Instead of grooves being provided in the internal walls of the interconnected holes, other formations such as scores or ridges may be provided to similarly increase surface area of the internal walls.

References

• CA 2115998 C

• CN 1325394 C

• DE 1945810 A1

• EP 1237826 A1

. US 5405905 A

• US 20070287795 A1

• US 5897953 A

• US 6524849 B1

• WO 2013098340 A1

• WO 2003018160 A2

• WO2014077183 A1

Claims

1. A composite bio-granule for a planting medium, the composite bio-granule comprising: a body formed from a mixture of marine clay, pumice, activated carbon and a binding agent; and

a plurality of interconnected holes in the body, each hole extending from an exterior surface of the body into a core of the body.

2. The composite bio-granule of claim 1 , wherein each hole is radially provided such that the plurality of interconnected holes intersect at a geometric centre of the composite bio- granule.

3. The composite bio-granule of claim 1 or claim 2, wherein diameter of each of the plurality of interconnected holes increases towards a geometric centre of the composite bio- granule.

4. The composite bio-granule of any preceding claim, wherein the plurality of interconnected holes are equidistantly provided on the exterior surface.

5. The composite bio-granule of any preceding claim, wherein internal walls of the plurality of interconnected holes are configured to have increased total surface area for increased bacterial colonization.

6. The composite bio-granule of claim 5, wherein the increased total surface area is formed by providing grooves on the surface of the internal walls.

7. The composite bio-granule of any preceding claim, wherein ratio of the marine clay : pumice : binding agent : activated carbon is 3 : 1 : 0.5 : 0.5.

8. A planting medium comprising a plurality of the composite bio-granule of any one of the preceding claims.