لجن
narrower: لجن فعال
narrower: لجن اسیدی
broader: شیمی تجزیه
preferred label: sludge @en
type: Concept

لجن فعال
preferred label: activated sludge @en
type: Concept
broader: لجن

شیمی تجزیه
preferred label: analytical chemistry @en
type: Concept
narrower: لجن

لجن اسیدی
preferred label: acid sludge @en
type: Concept
broader: لجن