Hazardous or toxic waste destruction or containment – Containment – Solidification – vitrification – or cementation
Patent
1997-08-29
1999-10-19
Suchfield, George
Hazardous or toxic waste destruction or containment
Containment
Solidification, vitrification, or cementation
588236, 134 13, 210913, 405128, A62D 300, B09C 102, B09C 108
Patent
active
059679654
ABSTRACT:
A method for treating heavy metal contaminated soils, particularly those containing hexavalent chromium, which includes a first soil washing at pH 9-12 with an anionic synthetic organic flocculant followed by a liquid-solid phase separation such as by gravity separation including sedimentation, an optional second soil sludge washing at pH 2.5-3.0 with addition of a metal valency reducing agent which when done is followed by a second liquid-solid phase separation using a cationic synthetic organic flocculant, combining the first and second stage liquids and optional treating the liquid phase with a metal valency reduction agent such as sodium metabisulfite under acidic conditions followed by treatment with an alkaline agent to form insoluble metal hydroxide which is separated in a phase separation process and is combined with the final sludge, recycling the liquid from washing stage or stages for use in soil processing, dewatering the separated sludge or sludges using a separation method (e.g. pressure filtration, centrifuge, etc.) and treating the dewatered sludge with an alkaline reagent, such as dry lime dust, lime slurry, potassium or sodium hydroxide thus resulting in metal immobilization within the treated soil in the hydroxide form.
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Diglio Peter J.
Kigel Mark Y.
Kofman Mikhail
Pica Gerard N.
Riggi Salvador A.
Envirem
Stone Robert L.
Suchfield George
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