Tributyl Tin (TBT) is an active ingredient in certain antifouling paints used to coat the bottom of ships to prevent sea life such as algae and molluscs attaching themselves to the hull. However these compounds persist in the water killing sea life and harming the environment.
Land & Water were contracted to carry out the maintenance dredging at the entrance to A & P Dry Dock No 2 and the adjacent areas of quayside to a specified profile. The area of dredging was heavily contaminated with TBT and heavy metals resulting in the arising silts having to be stabilised in lagoons on site before being transferred in sealed wagons to Teeside for final disposal at an approved landfill Site.
Dredging was undertaken using a 40 tonne long reach excavator equipped with a lidded “Eco-Bucket” and mounted on a 12 section Raverstein Pontoon. All works were carried out within a Silt Curtain to prevent the migration of sediments during the works. The dredged profile was accurately controlled using a Trimble Dig Control System mounted on the excavator.