The fumigation treatment carried out on ship's warehouses is a practice that has been carried out for more than 50 years and tends to take advantage of travel time as an exposure period. In this type of treatment there are four stages: PREPARATION, APPLICATION, EXPOSURE, VENTILATION.
REPARATION: This is where all the strict and detailed controls of the warehouses and their connections with other compartments of the ship are carried out. The stage of defining the method to be used and its need to condition the cellar before being loaded (J System recirculation method) begins. Once finished, the loading of the ship begins, where only the state of the merchandise is supervised.
PPLICATION. This is where you must define the dose of fumigant to apply, the personnel that will work in each of the warehouses, and the equipment that requires. EXPOSITION. This is called the period where the fumigant, in its highest concentration, will be in contact with the merchandise and with the alleged pests to make a total or partial control. This period is the one that in this type of fumigation is used with the transit time and is only monitored during unloading.
XPOSICION. Este se denomina al periodo donde el fumigante, en su más alta concentración , estará en contacto con la mercadería y con las supuestas plagas para hacer un control total o parcial. Este periodo es el que en este tipo de fumigación es aprovechado con el tiempo de tránsito y solo es monitoreado a la descarga.
ENTILATION. Once the stipulated time of exposure has expired, the captain of the ship has the responsibility to ventilate. That is to say, opening the caps of warehouses and allowing the phosphine gas to dissipate in the environment and reduce the concentration inside the warehouses. For this task, adequate equipment of safety and measurement is given to the crew. This reduction in the concentration of phosphine is the one that will allow, once the ship enters the port, to have a safe unloading.
This is the simplest and least safe method. It consists of randomly throwing the tablets of the fumigant and trying to distribute it all over the surface of the cellar.
The disadvantage of this method is that in transit the merchandise can be moved and with it the tablets, running the risk of being concentrated in a certain place and its concentration of gas is greater to the point of flashing generating localized fires.
DOCIFICATION BY ZONDA.
Here spears are used where they can put the tablets buried no more than 1.5 meters but enough to prevent them from moving. This avoids the risk of fire due to gas accumulation. This method is the most used in South America.
WASTE HOLDER SLEEVES
What is done here is to place the fumigant in sleeves of non-woven fabric or bags of cotton cloth in amounts no greater than 100 tablets per sleeve. The sleeves are tied together and placed in rows or star shaped on the surface of the load. This method prevents that the residue or ash that generates the reaction of the aluminum phosphide with the ambient humidity, does not remain deposited on the load. For this method, it is necessary to give clear instructions to the crew for the deactivation of the waste. This same treatment in some opportunities is performed by representatives of the fumigation company at the destination. The method of sleeves is made only by requirement of the country of destination or by some particular specification.
RECIRCULATION J SYSTEM
This method, that we named in the preparation stage, consists of placing pipes on the bottom of the cellar with an elevation through the passage of man. An electric blower is placed at the upper end which forces the phosphine to reach the bottom of the cellar. The recirculation is used when the transit is short or when a high dose is required and to avoid high superficial concentrations.
HDS is very useful in situations where a high amount of phosphine is required in a short time. The HDS 800 is capable of applying up to 200 grams per minute, whereby a cellar of 5,000 cubic meters can be injected with phosphine and the gas distributed in about an hour. This minimizes labor, eliminating the risk of fire in the fumigation process. It is also not necessary to enter confined spaces and avoid fumigant manipulation by operators. In addition, this technology does not leave any solid or liquid residues to collect and dispose of after fumigation. The ventilation process of these facilities is fast, since once the gas injection is finished, phosphine is not generated inside because it does not have metallic phosphides present. This method is currently undergoing experimentation in Argentina.
FUMIGANTE The product used is ALUMINUM FOSFURE in its commercial presentations. Pellets and tablets the containers can be of the most diverse. Bottles of one kilogram, bottles of 1.5 kg, buckets of 7,000 tablets, sachet, etc.