GB2249972A

GB2249972A - Material or composition for entrapping or absorbing gases or liquids

Info

Publication number: GB2249972A
Application number: GB9122271A
Authority: GB
Inventors: Donald Charles Stanley Savage; Ian Michael Robinson
Original assignee: ODOURFREE Ltd
Current assignee: ODOURFREE Ltd
Priority date: 1990-10-19
Filing date: 1991-10-21
Publication date: 1992-05-27
Also published as: GB9122271D0

Abstract

Fly ash is used, with or without one or more additives, as a gas entrapping material or composition, as a liquid absorbing material or composition, as fire extinguishing material or composition, as a litter composition or material for domestic animals or pets or as a farm animal feedstuff additive. The properties of the fly ash may be enhanced for a particular intended use, by the introduction of additives, e.g. an acid salt. The entrapped gas may be ammonia produced in a farm e.g. maggot farm, or radon. Compositions comprising fly ash, sawdust and ferrous sulphate in specified amounts are claimed.

Description

MATERIAL OR COMPOSITION FOR ENTRAPPING OR ABSORBING GASES OR LIQUIDS ETC.

This invention relates to a material or composition having in practice a variety of uses such as the entrapping of gases, e.g. those producing noxious odours, such as NH 4 released from manure generated by farm or domestic animals; those that present a health hazard such as radon released naturally from granite and other formations; for absorbing liquids e.g. oil spillages; for fire extinguishing; and as a litter for domestic animals or pets.

With modern high intensity farming techniques used in poultry, pig, cattle and calf units, control of atmospheric ammonia, released from the urine or faeces, is the subject of ministry regulations as to the working times permitted for personnel, specifically 8 hrs. for < 25 part per million, and 15 mins for > 35 parts per million.

Although consistently achieving an ammonia level of < 25 parts per million could be achieved by ventilation alone, this is costly if a positive air flow through a unit were to be required, as fans (rather than simply providing controllable ventilation apertures) would require installation and would involve running and maintenance costs.

Furthermore, additional heating costs would be incurred in winter unless diminished production were to be accepted.

Ventilation requirements, whether natural or forced can be diminished by the use of zeolites, but of course zeolite purchase also increases unit production costs, whilst some cheaper zeolites contain heavy metal contaminants which tests have shown are sometimes ingested, particularly by poultry.

According to a first aspect of the present invention there is provided the use of fly ash, with or without one or more additives, as a gas entrapping material or composition.

According to a second aspect of the present invention of independent significance, there is provided the use of fly ash, with or without one or more additives, as a liquid absorbing material or composition.

According to a third aspect of the present invention of independent significance, there is provided the use of fly ash, with or without one or more additives, as a fire extinguishing material or composition.

According to a fourth aspect of the present invention of independent significance, there is provided the use of fly ash, with or without one or more additives, as a litter, composition or material for domestic animals or pets.

Thus, the base material in accordance with the invention is fly ash, which is a readily available waste byproduct produced annually in quantities of many thousand tons at power stations using pulverised coal as fuel, and in fact such quantities of fly ash has presented a major disposal problem to power generators, usually having to be tipped at landfill sites, tipped into lagoons, or used in the manufacture of breeze blocks.

Thus, the base material in accordance with the invention is powdery fly ash, typically having a particle size such that 100% passes through a 500 standard mesh sieve. Such fly ash also has a high bulk density.

Thus, whilst the base material in accordance with the various aspects of invention is fly ash, the properties of this material may be enhanced for a particular intended use, by the introduction of suitable additives.

For instance, with the first mentioned use, such use may simply be to achieve reduction if not elimination of unpleasant odours to the advantage of personnel in the vicinity of an odour producing environment such as a pig, poultry, maggot etc., farm, a sewage works, etc., with the material or composition being used principally to entrap ammonia released from manure or sewage. Furthermore, the material or composition may be used with advantage at industrial locations such as chemical plants producing noxious fumes and/or residues and/or products, whether solids, liquids or slurries.

In the case of entrapping a gas where no unpleasant smell is involved but where the gas is potentially harmful to humans, e.g. radon, then the material or composition may be provided in a filter unit located in a building or dwelling susceptible to gas, e.g. radon ingress, with a fan or other pump adapted to circulate air within the building or dwelling through the filter unit.

Other target gases that may require entrapment, suppression or removal for reasons of odour and/or harmful effect may be equally effectively treated by the material or composition of the invention, and such other gas may for instance be chlorine.

In the case of fire extinguishing, as fly ash is basically pure silica, it is extremely effective as a fire extinguishing composition when applied, by any convenient means, to the flames to be extinguished.

In detail, for use where the target gas is ammonia produced from manure or sewage, an acid salt additive is preferably incorporated in the fly ash. By the term acid salt is meant a salt of a strong acid with a weak base, or one in which only part of the acidic hydrogen as been replaced with metal, and in solution acid salts have a pH lower than 7.

Examples of such salt include ferrous sulphate heptahydrate, aluminium sulphate, iron chloride, sodium bisulphate and like nitrates, sulphates and chlorides of e.g. Al, Zn, Fe, Cu, Mn, Co and Ni.

Furthermore, a further additive in the form of a natural cellulose fibre may be included. The natural cellulose fibre may conveniently take the form of sawdust.

The composition of the present invention may be pelletised or granulated. This may be done by mixing the composition with a suitable amount of binding agent and extruding the mixture to form a cylindrical product which can be broken down if desired to shorter lengths. Alternatively, the mixture may be granulated in a rotating drum ensuring that enough liquid phase is present during granulation by e.g.

adding water. Any of these steps may be performed at an elevated temperature.

Suitable binding agents include water, clay, methyl cellulose, blood, and the like.

The granules or pellets may have, e.g. an average size in the range 0.1 to 0.3 inches (2 - 8mm) but circumstances may favour the use of larger or smaller size material.

Considering one specific use - the suppression of ammonia released in the course of maggot farming, the composition of the present invention may be introduced at any of one or more of the stages during the maggot production cycle. For instance, in one mode of raising maggots, the maggots and/or their blow (maggot larva) are placed on the base of a bed or vat and covered with a layer of feed material which is usually waste meat or fish. After 5 to 10 days, possibly longer in cold conditions, the maggots are retrived together with feed residues and then subjected to a suitable dressing stage.

This aspect of the invention therefore provides a process for treating maggots and/or their blow which comprises contacting the maggots and/or their blow during and/or after their growing period with the composition as defined above.

Such contact may be achieved by one or more of the following steps: 1. providing a layer of the composition in the bed or vat before adding the maggots and/or their blow thereto; 2. scattering a layer of the composition onto the maggots and/or their blow while in the bed or vat but before adding the feed material; 3. scattering a layer of the composition onto the maggots and/or their blow while in the bed or vat after adding the feed material; 4. scattering a layer of the defined composition onto the maggots and/or their blow after removal from the bed or vat but before dressing; and 5. scattering a layer of the defined composition onto the maggots and/or their blow during or after dressing.

The process of our invention results in a very significant reduction in extremely malodourous fumes which normally characterise the domain and surroundings of a maggot farm.

Example Fly ash 45 parts by weight, sawdust 45 parts by weight and a 20% aqueous solution of ferrous sulphate 10 parts by weight were mixed together and fed to a rotating drum where they were tumbled together to produce granules ranging in size from 0.1 to 0.3 inches (2 - 8mm).

When the granules were scattered in the environs of the maggot house, the odour levels were reduced very significantly.

Continued use had a similar effect in the area surrounding the maggot arm.

Thus, fly ash, with or without performance enhancing additives, may be distributed, e.g. sprinkled - as powder, dust, or granular form onto the floor of a farming unit.

Such distribution may be to both the walkways where personnel have access and to the pens, the latter resulting in the intermixing of the fly ash with the animal droppings and hence suppression at source of ammonia emission to the atmosphere.

Alternatively, or in addition, may be discharged as an airbourne dust into a farming unit, e.g. at a ventilating air inlet or fan.

According to another, fifth, aspect of the invention, there is provided the use of fly ash as an additive for farm animal feedstuffs.

According to a sixth aspect of the invention there is provided a farm animal feedstuff incorporating a proportion of fly ash.

These aspects provide: (i) for suppressed ammonia emission and hence reduced ventilation requirements; (ii) the avoidance of zeolite purchases; and (iii) an efficiency improvement.

Fly ash, being virtually pure silica, is harmless to animals and, when incorporated in their feedstuff, e.g. from 1% to 10% or more, avoids the need for some if not all fly ash distribution by the workforce in that, after passage through the animals digestive system, it is deposited intimately mixed with faeces, as droppings, and hence has immediate and most effective ammonia absorbing effect.

Claims

1. The use of fly ash, with or without one or more additives, as a gas entrapping material or composition.

2. The use of fly ash, with or without one or more additives, as a liquid absorbing material or composition.

3. The use of fly ash, with or without one or more additives, as a fire extinguishing material or composition.

4. The use of fly ash, with or without one or more additives, as a litter composition or material for domestic animals or pets.

5. The use of fly ash as an additive for farm animal feedstuffs.

6. A farm animal feedstuff incorporating a proportion of fly ash.

7. A material or composition for use as a gas entrapping agent, comprising a mixture of fly ash and at least one acid salt additive.

8. A material or composition as claimed in Claim 7, wherein the acid salt is ferrous sulphate heptahydrate and/or aluminium sulphate and/or iron chloride and/or sodium bisulphate and/or like nitrates and/or sulphates and/or chlorides of e.g. Al, Zn, Fe, Cu, Mn, Co and Ni.

9. A material or composition as claimed in Claim 7 or Claim 8, comprising a further additive in the form of a natural cellulose fibre.

10. A material or composition as claimed in Claim 9, wherein the natural cellulose fibre is sawdust.

11. A material or composition as claimed in any one of Claims 7 to 10, provided in a filter unit located in a building or dwelling susceptible to gas e.g. radon ingress, with a fan or other pump adapted to circulate air within the building or dwelling through the filter unit.

12. A material or composition as claimed in any one of Claims 7 to 11, provided in a pelletised or granulated form.

13. A material or composition as claimed in Claim 12, comprising a suitable amount of binding agent.

14. A material or composition as claimed in Claim 13, which, after mixing, is extruded to form a cylindrical product which can be broken down if desired to shorter lengths.

15. A material or composition as claimed in Claim 13, wherein the mixture is granulated in a rotating drum ensuring that enough liquid phase is present during granulation by e.g.

adding water.

16. A material or composition as claimed in any one of Claims 13 to 15, wherein processing is performed at an elevated temperature.

17. A material or composition as claimed in any one of Claims 13 to 16, wherein the binding agent is one or more of water, clay, methyl cellulose, blood, and the like.

18. A material or composition as claimed in any one of Claims 12 to 17, wherein granules or pellets have an average size in the range 0.1 to 0.3 inches (2 - 8mm).

19. A material or composition comprising fly ash 45 parts by weight, sawdust 45 parts by weight and a 20% aqueous solution of ferrous sulphate 10 parts by weight.

20. A method of producing granules of the material of Claim 19, comprising mixing the constituents together, feeding the mixed constituents to a rotating drum where they are tumbled together to produce granules ranging in size from 0.1 to 0.3 inches (2 - 8mm).

21. A process for treating maggots and/or their blow which comprises contacting the maggots and/or their blow during and/or after their growing period with the composition, as defined in Claim 1 or Claim 2 and any Claim appendant to Claim 1 or Claim 2.

22. A process as claimed in Claim 21, wherein contact is achieved by one or more of the following steps:

1. providing a layer of the composition in the bed or vat before adding the maggots and/or their blow thereto;

2. scattering a layer of the composition onto the maggots and/or their blow while in the bed or vat but before adding the feed material;

3. scattering a layer of the composition onto the maggots and/or their blow while in the bed or vat after adding the feed material;

4. scattering a layer of the defined composition onto the maggots and/or their blow after removal from the bed or vat but before dressing; and

5. scattering a layer of the defined composition onto the maggots and/or their blow during or after dressing.

23. A method of reducing or eliminating maladourous fumes produced in a farming unit, comprising distributing fly ash, with or without performance enhancing additives, e.g. by sprinkling as powder, dust or granular form onto the floor of a farming unit.

24. A method of reducing or eliminating maladourous fumes produced in a farming unit, comprising distributing fly ash, with or without performance enhancing additives as an airbourne dust into a farming unit, e.g. at a ventilating air inlet or fan.

25. A farm animal feedstuff as claimed in Claim 6, comprising 1% to 1090 by weight, or more, of fly ash.