and nearly spherical shape of the particles are interesting and may represent the predominance of a single source of influent material. The process itself involves not only the nanoparticles present in the slurry but the removal of a substantial amount of material from the surface of the wafer. The process engineers indicated that, in most cases, the majority of this removed material is silicon, which is removed in sufficient quantities that it may be the majority contributor of non-water mass to the waste stream. This may explain the similarity in observedmaterial present at the slurry lift tank across several sampling events, despite the high likelihood that the specific wafers or slurry employed in the process will have changed between events.