There are two landfills in Dunedin: the council-owned facility at Green Island and the privately owned facility at nearby Fairfield. The Fairfield Landfill receives waste from the EnviroWaste transfer station in the Dunedin CBD, EnviroWaste’s private kerbside wheelie bin collections, and most of the gantry truck and front-loader truck waste collected by both EnviroWaste and Waste Management, the major waste operators in the region.23 Green Island Landfill receives waste from its on-site transfer station, the council’s kerbside bag collection and several small private waste operators.
The principal waste streams at the two facilities are therefore similar but not identical, with Fairfield receiving a higher proportion of Dunedin’s ICI waste, specifically that collected by front-loader trucks.24 As well as this important difference in the types of waste regularly discharged, the distribution of waste streams between the two facilities is not static, as shown by the substantial decrease in cover material discharged at Green Island after disposal charges were introduced. Anecdotal evidence indicates that the operators who had been disposing of cover material at Green Island shifted to disposing of the material at Fairfield Landfill.
The presence of an alternative waste disposal facility that accepts the majority of ICI waste transported by front-loaders potentially makes the waste stream surveyed at Green Island Landfill an unrepresentative sample of the waste from the region. The changing behaviour of waste operators transporting inert materials such as cover material also artificially changes the waste composition. Without a more complete view of waste disposal from the Dunedin region, particularly information on disposal at Fairfield Landfill, the data collected from Green Island Landfill may be unsuitable for measuring trends in the composition of waste going to landfill in the region.
23 Information obtained by observation of Fairfield Landfill while surveying at Green Island.
24 The front-loader waste at Green Island is discharged after hours, when Fairfield is closed. The front-loader trucks that discharge overnight at Green Island discharge at Fairfield during the day.