Underground Petroleum Storage Tanks and Related Wastes - Code ...

In addition, any person entering a confined space must wear safety harness and
safety rope, and be attended by a second person watching over him/her from
outside the tank, with breathing apparatus at hand. At least one other person must
be available, within call, to assist should it be necessary.
A Confined Space Entry Permit is shown in appendix 10.
11.13 Tank Cleaning
Once entry has been gained, the tank should be cleaned internally of any remaining
waxes and sludge. The external surfaces should also be cleaned in preparation
for cutting into manageable sections. Continue to cut the tank steel into appropriately
sized sections for subsequent removal to an approved furnace operation for
melting down.
The internal surfaces of the tank should only be handled when wearing gloves.
Additional protection such as a barrier cream applied to the hands may also be
used.
11.14 Scrap Tank Materials
Scrap steel cut from the tank must be flame cleaned or grit/shot blasted as set out
in Octel Instruction Publication No. 5-01/92, before being released from the site.
Any scale generated by cleaning operations and any other scrap materials from the
tank must be collected and treated as hazardous waste.
All storage, movement and disposal of scrap materials must be documented, as for
hazardous wastes. See section 12: Treatment and Disposal of Hazardous Waste.
12. TREATMENT AND DISPOSAL OF HAZARDOUS WASTES
12.1 Responsibility and Legal Requirements
It is mandatory for all parties involved in the cleaning of petroleum tanks to ensure
that the disposal of the residual hazardous wastes, e.g. leaded sludge and scale, or
scrap tank materials, is not in breach of local or central government regulations
applicable in the area where the operation is taking place.
Compliance with these requirements is the responsibility of the contractor.
12.2 Description of Leaded Petroleum Sludge
The residue remaining in leaded petrol storage tanks after all recoverable petrol
has been removed consists of liquid and solid matter. It is poisonous. Any tank
that has been used to store leaded product at any time must be considered a lead
hazard.
All lead compounds are toxic, and organic lead compounds are particularly poisonous.
They can be absorbed by breathing the vapour or dust, by swallowing dust
or dirt from face or hands, or by direct absorption through the skin.
The liquid consists of two phases:
• Water containing dissolved lead salts and some organic matter; and
• Hydrocarbons floating on the water.
The solids, formed mainly by the rusting of the steel tank, consist of a mixture of
iron oxides, water, petrol and, inorganic and organic lead compounds.
The following is a typical analysis:
Transport and Disposal of Petroleum Storage Tanks 23