Direct sludge freezing using dry ice

Dry ice was used as the heat sink in sludge freeze/thaw treatment. Four dis tinct sludges were frozen at four thermal contact configurations with dry i ce. Experimental results indicate that dry ice freezing can sufficiently co ndition the sludges and is an economically feasible alternative for sludge conditioning. With a properly designed thermal contactor, the freezing rate can range from 0.48-0.64 m daily. (C) 2001 Elsevier Science Ireland Ltd. A ll rights reserved.