The Collaborative International Dictionary of English v.0.48:

Sullage \Sul"lage\, n. [Cf. Suillage, Sulliage.]
   1. Drainage of filth; filth collected from the street or
      highway; sewage. [Obs.]
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            The streets were exceedingly large, well paved,
            having many vaults and conveyances under them for
            sullage.                              --Evelyn.
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   2. That which sullies or defiles. [Obs.]
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            It is the privilege of the celestial luminaries to
            receive no tincture, sullage, or difilement from the
            most noisome sinks and dunghills here below.
                                                  --South.
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   3. (Founding) The scoria on the surface of molten metal in
      the ladle.
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   4. (Hydraul. Engin.) Silt; mud deposited by water.
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   Sullage piece (Founding), the sprue of a casting. See
      Sprue, n., 1
      (b) .
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