Title of Invention	" A BIOLOGICAL FILTER FOR THE PURIFICATION OF WASTE GASES"
Abstract	A biological filter for the purification of waste gases, characterised in that a bed of biologically active carrier material consisting of pith extracted from coconut husks, the said bed contained fibre so as to the waste gases is brought in contact with the said bed and removed from the bed at points spatially separated from the inlet points

Full Text

This invention relates to a biological filter for the purification of waste gases and to the purification of air or gas streams containing odorous or toxic compounds by passage through a porous solid media containing micro-organisms which convert the contaminant compounds to oxidised products, thereby effecting, the desired purification. This invention, more particularly, relates to passing contaminated air through a bioactive biofilter media comprising retted coconut pith and coconut fibre, and to the selection, preparation and arrangement of the media. This invention achieves superior performance of biofilter by enabling adjustment of pressure drop to desired value, by providing adequate water retention, by providing a conducive environment for microbial growth, by using constituents which are natural, stable and environmentally compatible, by reducing cost of media and by reducing cost of transportation media. Background of the invention Biofilter systems are used in the purification of air streams. Biofilter systems have been applied for removal of odorous and toxic compounds in a wide variety of situation (Ottengraph S.S.P., Exhaust gas purification, Chapter 12, Biotechnology Vol. 8, Verlagsgesellschaft, Wienheim, 1986: VO1 Guidelines No: 3477 - "Biofilter", Verein Deutscher Ingenieure, Dusseldorf 1991). During the passage of air through the biofilter, micro-organisms such as bacteria and fungi which are active on the biofilter media, oxidise the toxic and odour substances present in the air stream to carbon dioxide water and mineral products such as mineral acids depending on the chemical constitution of the contaminant. The biofilter media is a critical component of the system providing physical support, moisture and nutrients for the microorganisms while ensuring sufficient contact with gases at low pressure drop. In this invention, the removal of odour and toxics from air is achieved by passing air through a biofilter comprising of retted coconut pith and coir fibre. In general, two types of materials have been used in biofilter processes - natural materials such as biocompost, peat, fibrous peat, and porous clays or synthetic materials such as plastics. The use of natural organic materials usually provides the nutrients required to support growth of microorganisms. The use of synthetic materials requires continuous addition of nutrients but allows better control of operation by facilitating the removal of acidity and degradation products. This invention falls in the category of natural material biofilters and one aspect of this invention relates to the selection, preparation and arrangement of the bed. There are only a few disclosures in the prior art regarding the We claim: 1. A biological filter for the purification of waste gases, characterised in that a bed of biologically active carrier material consisting of pith extracted from coconut husks, the said bed contained fibre so as to the waste gases is brought in contact with the said bed and removed from the bed at points spatially separated from the inlet points. 2. A biological filter as claimed in claim 1, wherein the bed of carrier material used is fibre . 3. A biological filter as claimed in claim 1 wherein the bed of biological material used is an acid neutralizing agent. 4. A biological filter as claimed in claim 3 wherein the acid neutralizing agent is calcium carbonate. 5. A biological filter as claimed in claim 1 wherein the bed used is a nitrogenous fertilizer material. 6. A biological filter as claimed in claim 2 wherein the content of the fibre in the bed is between 0.5 to 20% weight of the moist bed. 7. A biological filter as claimed in claim 2 wherein the bed of biologically active material is arranged as alternate layers of pith extracted from coconut husk and layers of fibre. 8. A biological filter as claimed in claim 7 wherein the in the alternate layers of fibre and coconut pith, the first layer at bottom of the bed is a layer of fibre. 9. A biological filter as claimed in claim 7 wherein in the alternate layers of fibre and pith the first layer at top of the bed is a layer of fibre. 10. A biological filter as claimed in claim 2 wherein the proportion of fibre to pith increases from the at least one outlet to the at least one inlet. 11. A biological filter as claimed in claim 7 wherein the said layers of fibre are constructed from non- woven fibre mat such as needle felt. 12. A biological filter as claimed in claim 1 wherein the said carrier material further contains activated sludge from an effluent treatment facility. 13. A biological filter as claimed in claim 1 wherein the said pith is extracted from coconut husks, which have undergone a retting process. 14. A biological filter as claimed in claim 2 wherein the fibre is coconut fibre. 15. A process for the purification of a gaseous stream containing oxygen comprising humidifying the gas, if required, and passing the gas through a bed of coconut pith. 16. A process for the removal of hydrogen sulphide from an air stream, comprising passing the air stream through a bed of retted coconut pith and coir fiber from an inlet section to an outlet section where the fibre content of the bed is high at the inlet section and low at the outlet section.

Documents:

468-DELNP-2003-Abstract -22-05-2008.pdf

468-delnp-2003-abstract-22-05-2008.pdf

468-delnp-2003-abstract.pdf

468-DELNP-2003-Claim-22-05-2008.pdf

468-delnp-2003-claim.pdf

468-delnp-2003-claims-22-05-2008.pdf

468-delnp-2003-correspondence-others-22-05-2008.pdf

468-delnp-2003-description complete-22-05-2008.pdf

468-delnp-2003-description complete.pdf

468-DELNP-2003-Drawing-22-05-2008.pdf

468-delnp-2003-drawing.pdf

468-delnp-2003-drawings-22-05-2008.pdf

468-delnp-2003-form-1-05-06-2008.pdf

468-DELNP-2003-Form-1-22-05-2008.pdf

468-delnp-2003-form-18- 22-05-2008.pdf

468-delnp-2003-form-2-22-05-2008.pdf

468-DELNP-2003-Form-3-22-05-2008.pdf

468-delnp-2003-form1-22-05-2008.pdf

468-delnp-2003-pct-101.pdf

468-delnp-2003-petition-138-22-05-2008.pdf