Disposal/Recycling

REL used a standard Waste Management Hierarchy  procedure, which has been developed over the last 23 years, as the foundation for generating the decommissioning cost estimate. This procedure has been independently checked and benchmarked against estimates produced by disposal & recycling contractors.

Waste Management Hierarchy

The waste management policy for dismantling an offshore structure will be based upon the Waste Management Hierarchy which has the principle aim of promoting ‘sustainable’ waste management solutions to minimise quantities going to landfill. The options in order of preference are:

1. Reduction
2. Reuse/Resale/ (Artifical reefs in non-OSPAR Regions)
3. Recovery/Recycling
4. Disposal

The option of Reduction of the amount of material coming ashore is not practical as there is pressure in the OSPAR Region to bring the material ashore rather than to dump it in deep-water. The majority of this material coming ashore will be steel, either structural or steel contained in the equipment itself, along with smaller quantities of other recyclable/disposable materials, and the possibility of encountering small quantities of hazardous wastes which may require specialist disposal.

Determining Disposal Options Available

The key to determining the disposal options available for the waste materials arising from the dismantled structure will be the residual materials on the structure (i.e. the materials of construction and any residual materials remaining after decommissioning).

Although it has already been stated that the majority of material will be steel or equipment requiring processing, there is the possibility that it will more economical to dispose of certain materials, i.e. insulation, than to try and find a recycling market for them. That coupled with the possibility of encountering quantities of hazardous materials necessitate the presence of a fully established waste disposal trail during offshore structure dismantling activities.

The following sections will consider:

• Waste auditing under the principle of 'Duty of Care'.
• Waste packaging, handling and transport.
• Waste transfer/disposal documentation.
• Typical disposal routes.

Initial contacts have been made with waste disposal contractors to evaluate their capabilities for providing disposal services to a dismantling site during onshore deconstruction and disposal operations. Generally it was found that there are significant numbers of disposal sites available if required and sites local to the dismantling site will be more cost effective to use for wastes not requiring special disposal. There are many such sites and it is not intended at this time to detail the specifics of waste disposal. Section 4 considers the waste management capability of North Sea littoral states in more detail, again this will be done on a national level rather than on an individual site basis.

Deconstruction Schedule

The deconstruction schedule is calculated on a weight basis and an estimated deconstruction rate assumed by "y" tonnes per day for a crew of "x" men and associated equipment.

For the purpose of estimating the recovery of the disposal costs due to the sale of scrap materials, a preliminary estimate of the basic material groupings can be made using current regional prices. The material breakdown, which reflects the more modern J6A design


Waste Disposal

The key to determining the disposal options available for the waste materials arising from the dismantled structure will be the residual materials on the structure (i.e. the materials of construction and any residual materials remaining after decommissioning).

Although the majority of material will be steel or equipment requiring processing, there is the possibility that it will more economical to dispose of certain materials, i.e. insulation, than to try and find a recycling market for them. That coupled with the possibility of encountering quantities of hazardous materials necessitate the presence of a fully established waste disposal trail during offshore structure dismantling activities.

A typical work sequence would consist of :

• Waste auditing under the principle of 'Duty of Care'.
• Waste packaging, handling and transport.
• Waste transfer/disposal documentation.
• Identification and selection of typical disposal routes. (Local routes where possible)

Part of the process would involve contacting the local/nearest waste disposal contractors to evaluate their capabilities for providing disposal services to a dismantling site during onshore deconstruction and disposal operations. Generally there are significant numbers of disposal sites available if required and sites local to the dismantling site will be more cost effective to use for wastes not requiring special disposal.
 

Typical Disposal Routes

Solid materials and other wastes (i.e. materials that cannot be re-injected or discharged) removed during decommissioning, preparation for removal and deconstruction will be returned ashore for disposal at authorised sites. The disposal option selected will depend on the composition of the material and in generic terms, the options include:

  • Re-use - this could apply to items of equipment (e.g. pumps, compressors, separators, generators, cranes, portable equipment) some chemicals (e.g. refrigerants, Halon, un-used chemicals, bulks) or indeed the complete structure.

  • Re-cycle - this could apply to any metallic materials (e.g. structural steel, iron ore ballast, copper wiring), waste oils and solvents.Landfill - this disposal route could apply to non hazardous materials such as materials removed from the accommodation; certain landfill sites are also licensed to accommodate hazardous materials, such as asbestos.

  • Incineration - this disposal route could be used for disposing of hazardous materials, such as residual chemicals and materials containing PCBs.Specialist

  • Disposal - this includes a number of specialist treatment plants (either to neutralise or to dispose of materials). Of particular relevance will be the treatment and disposal of LSA.

In the case of chemicals, biocides and oil contaminated materials a chemical analysis will need to be conducted to determine the chemical composition and/or level of contamination before disposal at a suitably licensed site.

Certain countries will not have the facilities nor give permission for the disposal of some of the following wastes. This issues will be addresses on a case-by-case basis.
 

 



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