Material flows in the waterjet industry : an environmental perspective

Sammanfattning: Abrasive Waterjet cutting (AWJ) presents many advantages over competing machining techniques, but several issues are related to the high volume of materials (and in particular of abrasive) used in the process. In this study, the environmental impact of the material flows in the abrasive waterjet industry has been analyzed adopting a life cycle perspective in order to individuate which phases place the largest burden on the environment. Moreover, three alternative abrasives (crushed rock, recycled glass and synthetic abrasive) and three disposal practices (in-site recycling, off-site recycling and recycling as construction material) have been also evaluated to estimate the benefits that can be achieved if these could be used in place of garnet abrasives and landfilling. The transportation of the abrasive resulted to be the phase that has the largest influence in every case and thus should be reduced as much as possible. For what concerns the alternative options, the usage of recycled glass and the in-site recycling of the abrasive were the two alternatives with the best environmental performances. However, crushed rock could be the best option for what concerns the global warming potential if carbon sequestration due to carbonation of silicate rocks is taken into account. Off-site recycling and recycling as construction material are good options only if the transportation to the recycling site can be reduced. Synthetic abrasive are instead found to have a much larger impact compared to every other alternative examined.