Puketutu Island Cleanfill has recently adopted new changes made to its site Fill Management Plan. These changes saw the introduction of on-site XRF (X-Ray Fluorescence) testing of incoming cleanfill, setting a benchmark for the New Zealand cleanfill industry.

Using XRF technology allows instant detection of heavy metal contamination in cleanfill. As a load enters the site, a sample is taken from the back of the truck and is analysed using the XRF equipment. If the test result is clean and material is acceptable, the truck is allowed to tip into the cleanfill. Unclean loads are rejected and sent off-site to landfill.

Material that when buried will have no adverse effect on people or the environment is categorised as cleanfill. Cleanfill material includes virgin natural materials such as clay, soil and rock, as well as other inert materials like concrete and brick that are free of:

combustible, putrescible, degradable or leachable components

hazardous substances

products or materials derived from hazardous waste treatment, hazardous waste stabilisation or hazardous waste disposal practices

materials that may present a risk to human or animal health such as medical and veterinary waste, asbestos or radioactive substances

liquid waste

Quarry rehabilitation

In addition to providing an environmentally responsible means for disposing of earthworks material, cleanfilling also aids the rehabilitation of quarry land into a reusable landform. Puketutu Island has been cleanfilling since 1988. A final landform, subject to ongoing consultation, will be created using the incoming cleanfill to produce contours with clean clays and soils used for capping.

Winstone Aggregates operates cleanfills at Puketutu Island, Wiri North, Wiri South and Watercare Pond 2 (Auckland), Dry Creek (Wellington) and Yaldhurst (Christchurch).