Toxic Substances have so far been used to
control/destroy insects e.g. Ethylene Dioxide is used for disinfestation
of foods but these toxic substances are coming in for increasingly
stronger criticism. Substances like Methyl Bromide, Hydrogen Phosphide
etc. also face the problem of residues seriously.
Therefore, research was undertaken to substitute and supersede such
chemicals with natural residue-free and environment friendly
disinfestation processes. In this new process of fumigation evolved the
originally packed agricultural product is exposed to pressurized CO?
atmosphere. The infestation is done on the optimum condition and cycle
time of few hours is required for the products which have to be
fumigated. No special pre or after treatment is necessary. Products are
taken to a special enclosure and the enclosure is flooded with gaseous
CO2 to the required final pressure and the subsequent expansion takes
place in another vessel.
By avoiding the use of the so far commonly employed poisonous gases,
with a procedure of pressure disinfestations with Carbon Dioxide (CO2),
the procedure is environmentally compatible and thereby eliminates the
problems of residues.
Carbon dioxide can be obtained out of the following six processes :-
- From thermal decomposition of limestone, CaCO3, in the manufacture of lime,ie, CaO.
- As a byproduct of sodium phosphate manufacturing process.
- CO2 emerges as a byproduct in ammonia and hydrogen plants, where methane is converted to CO2.
- From combustion of wood, fossil and petro fuels like deisel, kerosene, natural gas etc.
- As a byproduct of fermentation of sugar in the brewing of , and other.
- Directly from natural carbon dioxide springs, where it is produced by the action of acidified water on limestone.