This paper describes the waste management challenges, strategies put in place and lessons learned with managing waste from one of the largest steel jacket and platform decommissioning projects in the North Sea against a commitment to reuse and recycle 97% of the removed structure.
The North West Hutton (NWH) platform was installed in 1983 and comprised an 18,000 tonne steel jacket support structure and 20,000 tonnes of topsides modules. In waste management terms this converted the platform to metals, glass reinforced plastic, hydrocarbon sludge, oils, production chemicals, drilling chemicals, asbestos, PCBs and radioactive materials etc.
Part of the waste management challenge was to identify and quantify materials present and then to have a clear strategy in place for the removal of hazardous waste offshore with decisions made as to how ‘clean’ should clean be and what waste materials should be left in situ and handled during onshore dismantlement. A further challenge was then to quantify waste per separated section for removal and consignment onshore as required under UK regulations and for onshore management planning.
The project was one of the first of its kind in the UK sector and as such the information provided in this paper will be of interest and use to any other Operator planning any decommissioning activities.
In terms of conclusions the Operator is well on its way to achieving the 97% reuse and recycling of NWH. As well as this there was much learned, which included:
The benefits of good early upfront planning;
Good document management right through an installation's life time;
A clear waste management plan and strategy, developed together with the Decommissioning Contractor and Onshore Dismantlement and Disposal Contractor;
Early and ongoing consultation with regulators;
Some methodologies used to estimate worst-case hazardous waste quantities can grossly over estimate actual quantities present.
As one of the first of its kind in the UK the NWH project provides information and lessons learned on the quantification and management of hazardous waste offshore, removal and consignment of topsides sections with residual hazardous waste as well as legislative interpretation and compliance.