'Phytocap' landfill research receives $734,000 grant

Researchers at Melbourne University have been awarded a $734,000 grant from the Australian Research Council to evaluate and develop a new planted-soil capping technology for landfills known as phytocapping ('phyto' = plant).

To be conducted at five sites around Australia, the research program will determine whether phytocaps can perform more effectively, sustainably and economically than conventional landfill caps.

The CEO of the Waste Management Association of Australia (WMAA), Ms Val Southam, explained that landfills remain the major means of waste disposal in Australia and a significant potential source of environmental contamination if not managed appropriately. "Conventional landfill covers such as compacted clay caps control percolation of rainfall into the landfill waste zone by acting as low permeability 'raincoats'. Unfortunately, they can deteriorate and leak, which in turn produces landfill leachate and, therefore, potential for groundwater contamination. It is difficult, expensive and often impossible to repair these leaks," she said.

Phytocaps, on the other hand, work with rather than against the forces of nature, Ms Southam said. "They function as 'store and pump' mechanisms - an earth layer typically about a metre in depth stores water during rainfall events and the plants then act as 'solar pumps' to remove the stored water through plant transpiration. This can provide a more effective and less expensive alternative for controlling percolation. Moreover, because phytocaps are living systems they can 'self-repair' any faults that might begin to develop, making them more sustainable."

The research is set to begin in early 2006.