Contract Environmental (visit www.cenv.co.nz ) a subsidiary of CLL Service and Solutions, were contracted to remove asbestos and mercury from Transpower’s Haywards Pole 1 facility.
Contract Environmental (CE) had already carried out similar work on the Benmore facility. Both were scheduled for deconstruction as part of the upgrade of the HVDC inter-island electricity transmission system.
CE’s requirement was to remove asbestos and clean the site of mercury with various chemical cleaning methods.
The HVDC line historically used old mercury rectifiers with significant amounts of mercury spilt in maintaining the rectifiers. An analyser was used to measure mercury concentrations in the concrete and it was found in areas throughout the building. An extreme weather event had caused flooding in the building with the water coming in contact with mercury contaminated concrete. The water was sampled and disposed of appropriately.
Any difficulties with mercury cleaning and asbestos removal were worked through with the help of lessons learnt in Benmore. Work was carried out with hand tools as power machinery cannot be used with asbestos.
Both mercury and asbestos removal went smoothly although investigation by CE showed considerably more asbestos in the building than initial investigation had indicated. Foamshield technology proved an effective solution for preventing airborne fibre release, thus reducing asbestos health risks.