The Hunter Water project involved the hazardous material removal and demolition of a former Water Treatment Plant at Tomago NSW.
The large above concrete structure contained over 3000 tonnes of concrete and brick that required the use of large scale concrete shear attachment due to the heavy reinforcing steel present. Initial access was required to be created to accommodate the pumping out of two of the concrete tanks under strict environmental controls. Access was also required for small machinery and skilled personnel to undertake the removal of asbestos mastic material from every structural joint within the above ground structures. This involved full depth saw cutting either side of each joint followed by manual and machine removal of the mastic material and impacted concrete. Each tank was cleared by a third party hygienist prior to the demolition of the concrete to enable safe off-site recycling.
Given the heavy reinforcing, the contra required additional pulverising to remove the rebar prior to loading. In excess of 70 tonnes of steel, reinforcing was removed from the concrete for recycling. Fines material (less than 50mm) produced from the pulverising activities were subsequently reused on site to backfill the deep voids associated with the former sand filtration beds at one end of the structure.
In addition to the large concrete structure, two large steel framed gravity feed water tanks were safely demolished using induced collapse techniques. Ecological requirements were satisfied through a careful pre-demolition survey conducted for the presence and removal of micro bats within the structure. In addition, several large snakes were carefully relocated to the adjacent bushland during the works.
VENM fill sand was imported and guarded across the area to fill voids from the demolition works and the entire area re-grassed for future safe maintenance by Hunter Water personnel.