| 摘要 |
Sewage sludge for use in soil improvement is decontaminated and dried in a process in which the raw sludge, de-watered in a centrifuge or decanter, is heated to 70-75 deg.C., using flue gases and vapour from a drying equipment, in a stirrer or agitator, with addn. of acid. After filtering in a centrifuge, the sludge is mixed with waste material dust, e.g. sawdust, to give granules, which are dried at a temp. below 115 deg. C. Heavy metals are pptd. from the filtrate with Ca hydroxide.
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