| abstract |
An industrial waste water containing hexane soluble impurities is adjusted in pH to a value of at least 11.6 and thereafter calcium chloride is added to that waste water in an amount of at least 1,700 parts per million, based on the total weight of industrial waste water. A metal hydroxide floc results which includes a substantial portion of the hexane soluble impurities attached to or incorporated in the floc. The floc can be agglomerated with conventional coagulants and then separated from the clarified waste water. The calcium chloride will react at this very high pH to effectively flocculate a substantial portion of the oils and greases (hexane solubles) in addition to a substantial portion of the contaminating metal ions in the industrial waste water. |