Assertion: sewage's material | /r/HasProperty | skimmed
Facets:
value: from the water surface
type: LOCATION
value: during primary treatment
type: TEMPORAL
Source sentences:
text: In most POTWs, the floating material (oil, grease, wood, and vegetable matter) that is skimmed from the water surface during primary treatment is disposed of separately and does not become part of the primary sludge.
text: Settled solids are scraped from the bottom, and floating material is skimmed.