Better use for shell grit wins CCAA award

She shares the award with collaborators John Toft (Landscape Design) and Peter Flemming (Environmental Coordinator, Cockburn Cement).

The winning project involved using shell grit, which is a mixture of shells and seaweed, as mulch for trees and plants in rehabilitation sites at the Cockburn Cement Ltd (CCL) Munster site.

?Shell grit is a by-product of dredging operations in Cockburn Sound. If it is used in the cement making process, the potential for increased gaseous emissions rises,? Dr Ruthrof said.

?By using it as mulch to support revegetation, we?re not only helping revive the quarry environment, but we?re finding a productive use for a by-product that would otherwise simply go to waste.?

Plants were monitored for one year, with an impressive survival rate of 80 per cent.

?Typical survival rates depend on factors such as the season, soil type and species, but 80 per cent is generally considered very successful for seedlings,? Dr Ruthrof said.

?No one has used shell grit as mulch before, so the outcome was very encouraging. The material?s water retention qualities exceeded our expectations, with bunds along haul roads requiring watering only twice per week during summer, instead of three or four times per week under previous conditions.

?Given Western Australia?s climate and water situation, this is obviously a great result.?

The material stands to be a cost-effective, innovative way to reduce a constant environmental challenge for CCL.

Dr Ruthrof said she and the team at CCL were looking at the beneficial properties of shell grit and further industrial uses for it.

Source: Murdoch University

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