SLUDGE CHEMICAL-COMPOSITION CHANGES UNDER UNIDIRECTIONAL FREEZING

The chemical compositions changes for waste activated sludge at differ ent freezing speeds were analyzed via FTIR spectra. With a high speed of freezing, the chemical compositions are little influenced by the ac tion of ice formation; while with a low speed of freezing, the chemica l compositions are largely affected. The prerequisite for sufficient d ewaterabitity improvement is found as the global floc migration owing to the ice front formation, which releases some ECPs (basically cellul ose) from the sludge and alter the resulting cake structure ultimately . Copyright (C) 1996 IAWQ. Published by Elsevier Science Ltd.