SLUDGE

SLUDGE 化学特性,用途語,生産方法

• 解説

  汚泥，スラッジともいう。固形と液状の中間性状を示す泥状の廃棄物。鉱工業や農水産業の生産活動に伴って発生するのみならず，下水道，屎尿（しによう）処理，廃水処理などの公害防止施設などさまざまな分野から発生し，港湾，湖沼，河川やダムに堆積することも多い。生産活動で発生する汚泥には，例えば，溶液中で化学反応の後沈殿して生ずるもの，水による生産品の洗浄で生ずる不純物，有価物を抽出した後の残滓（ざんし）などがある。廃水処理では，水中の不純物を沈殿分離したり，活性汚泥処理で余剰汚泥を除去したり，ろ過による浮遊物質の捕捉（ほそく）回収などを行う過程で生成したりする。

• 定義

  Any thick, viscous mass, usually a sed- imented or filtered waste product. Examples are (1) aluminum ore tailings (red mud), (2) asphaltic petroleum residues, and (3) municipal waste (Imhoff and activated sludge). All these may be used as components of us

• 农业用途

  Sludge is a semi-liquid mass removed from the liquid flow of sewage. Domestic sewage containing more than 20% solid is also called sludge. The solids may contain nutrient and toxic elements, depending on the source of the sludge and its treatment.
  Sludge is disposed of by burning and burying it, or by adding it to water or soil. The preferred choice is to incorporate sludge into the soil, since this method does not pollute water. Disposal is more common than sludge utilization because of the potential health hazards, high transporting cost and low fertiliier value. Heavy metal con taminants are also a matter of concern.
  A potential use of sludge is in mine spoil reclamation. The sludge disposal can be done in soils having clay and organic content.