Wastewater treatment by radial freezing with stirring effects.
Radial freezing experiments on wastewater models were conducted in the presence of imposed stirring in order to remove impurities. The studied samples (dilute Na-montmorillonite suspensions charged with nitrates and with zinc or lead) were placed inside a cylindrical annulus, cooled at a controlled temperature around -7 degrees C at its inner wall which rotated around a vertical axis. The freezing front propagated toward the still outer wall which was maintained at a constant temperature around +1 degrees C. Thanks to stirring, considerable purification rates up to 99.97% were attained. It was also demonstrated that combining radial freezing and stirring ended in residual concentrations which agreed with drinking water standards.
Gay
Guillaume
G
Laboratoire des Matériaux et des Structures du Génie Civil (UMR 113), Cité Descartes, 2 Allée Kepler, Champs-sur-Marne 77420, France. guillaume.gay@ineris.fr
Lorain
Olivier
O
Azouni
Aza
A
Aurelle
Yves
Y
D005615:Freezing; D007854:Lead / Q000302:isolation & purification*; D009566:Nitrates / Q000302:isolation & purification*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014872:Water Movements; D018508:Water Purification / Q000379:methods*; D015032:Zinc / Q000302:isolation & purification*
D009566:Nitrates; D007854:Lead; D015032:Zinc