Cleaning contaminated sludges - by forming aq. suspension and circulating through washers and classifiers

摘要

Contaminated solids e.g. compacted solids from drainage systems, street sweepings, polluted earth, is injected with water to make a suspension, pref. with about 90 parts of water to 10 parts of solids, which immediately encounters an inclined sieve down which coarse solids fall. The residual suspension travels in a closed circuit at atmospheric pressure, with automatic adjustment of pressure in conveyors, buffer zones and control zones. Washing water is continuously supplied, and the circuit includes hydrocyclone washers confined with particle classifiers, below the liq. level in collector vessels. Semi-clarified washing water is retained for initial suspension formation, and residual washing water is fed into a settlement tank. ADVANTAGE - No complex controls are needed, and risk of blockage is reduced.