The changes of physicochemical properties of sludge during thermal drying were first described.Macromolecular organics in sludge were decomposed into micromolecule organics,and the forms of acid-soluble,oxidizable and reducible heavy metals were transformed into stable residue,which reduced the en-vironmental risk of sludge disposal.Then,the problems and causes of in thermal drying process of sludge were analyzed.Aiming at the problem of sludge vicosity,the methods of dry sludge back mixing,adding viscosity reducing substances and reforming drying equipment were summarized.In view of the pollution gas problem,this paper summarized the methods of adding additives and the reduction of temperature to inhibit the release of polluted gas,and the pollution gas was treated by absorption,adsorption and biologi-cal methods.In view of the equipment corrosion,the main measures of using anti-corrosion pipes,anti-cor-rosion coatings,adding corrosion inhibitors and reducing the sand content of sludge were summarized.Fi-nally,the suggestions on research trend and development of sludge thermal drying technology were pro-posed.
维普
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