Seed Waste

Infobox on Seed Waste
Example of Seed Waste
Facts
Origin	Chiefly South America, Asia
Stowage factor (in m3/t)	1,39 to 2,09 (m3/t)
Angle of repose	Not applicable
Humidity / moisture	See text
Oil content	See text
Ventilation	-
Risk factors	-

Seed Waste

Description

Seed Waste (further referred to as Seedcake) is the residue remaining after the removal of oil from any oil-bearing seeds, cereals and cereal products, and any other commodities with similar properties. This is achieved by mechanical crushing or by a process known as solvent extraction. Seedcake is a by-product of the production of vegetable oils from the oil-bearing seeds or grains, and is principally used as an animal feed or fertiliser.

With some exceptions (for example, solvent-extracted seedcake with low-residual oil and moisture, which is not regarded as hazardous), seedcake is a hazardous cargo that can self-heat owing to the presence of moisture, residual oil or both. Although the self-heating process is slow, it can cause the bulk temperature of the cargo to rise to the point at which it ignites spontaneously. The shipper is required, according to the provisions of the IMSBC Code, to provide a certificate from a person recognised by the competent authority of the country of shipment confirming the oil and moisture content of the shipment, on the basis of which the UN number of the cargo is determined.

The moisture content of a seedcake cargo is relevant since high moisture content promotes microbiological activity, which may be responsible for the initial rise in temperature up to about 70ºC and deterioration in the quality of the seedcake. This activity alone will not cause the seedcake to ignite, but it will accelerate oxidation of the residual oil, which in turn can cause the temperature to rise sufficiently to the point at which the seedcake will spontaneously ignite.

According to the IMSBC Code, seedcake derived from solvent extraction has an additional hazard arising from residual flammable solvent mixed in the cargo. Seedcake determined to be non-hazardous, and certified as such, is non-combustible and has a low fire risk.

It is important to measure the cargo temperature before and after loading, and during carriage to ensure that incipient signs of self-heating are detected and appropriate action can be taken. Digital thermometers of the type shown below are employed for this purpose.

There are four types of seedcake listed in the IMSBC Code defined by the oil and moisture content and the method of production. These are summarised below :

• Mechanically expelled seeds, containing more than 10% of oil or more than 20% of oil and moisture combined.
  
• Solvent extractions and expelled seeds, containing not more than 10% of oil and when the amount of moisture is higher than 10%, not more than 20% of oil and moisture combined.
  
• With not more than 1.5% oil and not more than 11% moisture.
  
• NON-HAZARDOUS
  

Solvent-extracted rape seed meal, pellets, soya bean meal, cotton seed meal and sunflower seed meal, containing not more than 4% oil and 15% oil and moisture combined and being substantially free from flammable solvents.

Seedcake is usually transported as a dry bulk cargo, in the form of pulp, meal, cake, pellets and expellers.

Self-heating and spontaneous combustion
The main hazard of seedcake cargo is the risk of self-heating and spontaneous combustion. Ships carrying hazardous cargo are required to have on board a valid document of compliance confirming the ship’s suitability for carrying dangerous goods. Self-heating leading to spontaneous combustion in a cargo of seedcake can be triggered by microbiological activity or exposure to a source of elevated temperature in the hold or both.

As with other dangerous goods, the IMSBC Code requires hazardous seedcakes to be kept as cool and dry as reasonably practicable, and stowed away from all sources of heat or ignition.

Sources of heat and ignition include:
• hot fuel oil tanks
• hot fuel oil lines
• hold lights left on
• poor electrical wiring
• carelessly discarded smokers’ materials
• engine room bulkheads

Documentation
The shipper/charterer shall provide the master or his representative with appropriate information on the cargo sufficiently in advance of loading to enable the precautions that may be necessary for the safe loading and the proper stowage and safe carriage of the cargo to be put into effect.

When the master is instructed to load a cargo that he is not familiar with, the master should request further information from the owner/operator or charterer.

Cargo information shall be confirmed in writing and by appropriate shipping documents prior to loading.

Documentation required on board a ship carrying dangerous goods
• Stowage plan
Each ship carrying dangerous goods in solid form in bulk shall have a special list or manifest setting forth the dangerous goods on board and the location thereof, in accordance with Safety of Life at Sea (SOLAS) regulations. A detailed stowage plan, which identifies by class and sets out the location of all dangerous goods onboard, may be used in place of such a special list or manifest.
• Emergency response
When dangerous goods in solid form in bulk are carried, appropriate instructions on emergency response to incidents involving the cargo shall be onboard.
• Certificate of fitness for ships carrying dangerous goods
Cargo ships of 500 gross tonnage and over, constructed on or after 1 September 1984, and cargo ships of less than 500 gross tonnage, constructed on or after 1 February 1992, shall have a certificate of fitness when carrying dangerous goods in solid form in bulk, except for class 6.2 and class 7 goods.

Hold cleanliness
The IMSBC Code requires the holds to be clean, and dry for all types of seedcake cargo.

Cargo claims involving seedcake cargo are commonly the result of contamination – often by residues from previous cargo. In order that such claims are avoided, the ship is required to ensure that holds are suitably cleaned, with all traces of previous cargo removed.

In many claims, holds are rejected prior to loading due to the staining of the frames and bulkheads from previous cargo, particularly coal and petcoke. Numerous claims involve cargo contaminated with dust, rust and scale from the tank top or bulkheads. Often, the amount of scale is considerable.

Hold preparation is an important part of the carriage and should not be underestimated. The master should seek proper guidance if he is unclear about the hold cleanliness requirements.

Cargo spaces are usually rejected due to remnants of previous cargo in upper parts of the hold,underside of hatch covers and on framing (where applicable).

Loading, stowage and segregation
Weather precautions
The IMSBC Code makes it clear that seedcake cargo shall be kept as dry as practicable. The cargo should not be handled during precipitation. During loading and discharge, all non-working hatches of the cargo holds into which the cargo is loaded or to be loaded should be closed. Masters and cargo officers should be aware of the prevailing weather conditions and have obtained a weather forecast. Before loading commences, clear communication should be put in place with those in charge of the shore-side operations over the action to be taken in the event of rain.

Trimming
Trimming a cargo reduces the likelihood of the cargo shifting and minimises the surface area available for air to enter the cargo. An increased air supply can promote spontaneous heating caused by oxidation of the residual oil in the cargo. To minimise these risks, cargo shall be trimmed reasonably level. The cargo should be trimmed in accordance with the relevant provisions of the IMSBC Code, as follows:

Due consideration shall be given to the amount of a solid bulk cargo in each cargo space, taking into account the possibility of shifting and longitudinal moments and forces of the ship. Cargo shall be stowed as widely as practicable to the boundary of the cargo space. Alternative hold-loading restrictions, as required by SOLAS, may also need to be taken into account.

The master has the right to require that the cargo be trimmed level, where there is any concern regarding stability based upon the information available, taking into account the characteristics of the ship and the intended voyage.

For more informed guidance on the trimming of cargo that flow, refer to the IMO International Code for the Safe Carriage of Grain in Bulk, according to which the term ‘grain’ covers wheat, maize (corn), oats, rye, barley, rice, pulses, seeds and processed forms thereof, whose behaviour is similar to that of grain in its natural state.

Hatch covers
Hatches of the cargo spaces carrying seedcake shall be weathertight to prevent the ingress of water. The majority of solid bulk cargo damage claims involve water in the holds, and seedcake is no exception.
A ship with leaking hatch covers may be subjected to claims of ‘unseaworthiness’.

Hatch cover maintenance
Ongoing maintenance and inspection are necessary to ensure weathertight hatch covers. In order to prevent hatch covers from leaking, ensure that:
• rubber packing is in good order
• compression bars are in good order
• channels and drains are clear of cargo and debris
• securing devices are working efficiently
• the steel fabrication of the hatch covers and coaming are aintained and not holed
• welding of hatchways must not be carried out when they are loaded with cargo

Ventilation
Mechanically expelled seeds, containing more than 10% of oil or more than 20% of oil and moisture combined, shall not be mechanically ventilated (except in an emergency) and caution is required when mechanically ventilating other hazardous seedcake cargo.

As previously discussed, a high moisture content of the cargo can cause self-heating through microbiological activity, producing temperatures in the region of 70ºC. Such elevated temperatures can accelerate the heat, producing oxidation of oil in the seedcake and causing the temperature of the cargo to rise further, possibly leading to spontaneous combustion. Steam is usually produced before the cargo takes fire.

Hazards of oxygen depletion
The oils in seedcake are liable to oxidise, causing a subsequent reduction of the concentration of oxygen in the air inside the cargo space. Additionally, carbon dioxide and carbon monoxide may be produced. Entry of personnel into cargo spaces for this cargo shall not be permitted until tests have been carried out and it has been established that the oxygen content has been restored to a normal level and carbon monoxide is absent, or at least at a concentration in which it is safe to work. Even when the hatch covers have been open for some time, the ladder access trunkings may still not be properly ventilated. Treat these spaces as enclosed spaces and make use of personal gas meters calibrated for oxygen and carbon monoxide.

Discharge
As much as possible, prior to arrival at the discharge port, consideration shall be given to:
• the requirements of the receiving country
• the draught survey
• the cargo surveys where applicable
• the discharge method/sequence
• ballasting
• ISPS
• the ship/shore safety checklist
• monitoring of gangway and moorings
• weather conditions during discharge

Clean up<br The level of cleaning undertaken in the holds following discharge of the cargo should be driven by the requirements of the next cargo to be loaded. Where the next cargo is unknown, holds should be cleaned to ‘grain clean’ standard.

Emergency Procedures
The temperature of this cargo shall be measured regularly at a number of depths in the cargo spaces and recorded during the voyage. If the temperature of the cargo reaches 55°C and continues to increase, the master should inform the owner/manager and seek expert guidance. Ventilation to the cargo space should be stopped and the hold should be sealed. Effective sealing of the hold may be sufficient to arrest the heat-producing oxidation reaction. This is because the oxygen is used up in the reaction faster than it can be replenished and the oxygen concentration in the hold then falls to a level at which the reaction can no longer be sustained. If, subsequently, ventilation of the cargo space is resumed, it is likely that the oxidation reaction will cause self-heating of the cargo also to resume. In the event that the cargo continues to self-heat after the hold has been sealed, the temperature within the hold should be assessed by any means available and the master will need to consider further fire-fighting measures, such as introducing carbon dioxide or inert gas to the cargo space.

Duties of the cargo officer
The cargo officer, usually the chief officer, should familiarise himself with the properties, characteristics and hazards of the cargo prior to loading. He should understand what measures need to be in place to prevent deterioration of the cargo or a dangerous situation occurring, and what to do should it happen. As per normal cargo operations, he will be responsible for ensuring:
• holds are prepared prior to loading
• cargo gear is in good working order, suitable for the intended work and conforming to Safe Working Load (SWL) requirements • documents are in order confirming that the shipment is safe for sea transport
• the recording of cargo condition and any pre-shipment damage
• removable hatch covers (where applicable) are stowed in such a place and fashion so as to not be damaged
• the ship’s fitness for loading and carrying the cargo (including access, lighting, guard rails, scupper plugs, fire-fighting, etc. where applicable)
• monitoring the ballast operations
• safe conditions for the working of stevedores on board
• the confirmation of loading/discharging quantities and procedures with shore-side
• the prevention of cargo damage during loading (including the closing of hatch covers during precipitation where applicable)
• that hatches are secure on completion of loading
• the isolation and stowage of cargo gear on completion of cargo operations
• monitor draught surveys/cargo quantity measurements
• communications with respect to cargo operations
• no smoking
• hold lights off and electrically isolated
• holds sealed as appropriate

Due to their oil and moisture content, this cargo can present a significant fire risk due to self-heating and spontaneous combustion.

Reference is made to the relevant IMO publications of hazardous cargo.

Full information on this product is in the process of completion.