Patent ID: 7087171

Claim:
A method for dewatering sewage sludge by using sludge-coal-oil co-agglomeration (“SOCA”), comprising the steps of: physically, chemically or biologically conditioning sludge to impart hydrophobicity and lipophilicity to the sludge (conditioning step); supplying oil and coal to the conditioned sludge with stirring to form sludge-coal-oil agglomerates comprising separated organic materials having a diameter of 500 μm or higher (agglomerating step); enlarging the particle diameter of sludge-coal-oil agglomerates to the range from 0.5 mm to 3.0 by increasing the agglomeration force of the sludge-coal-oil agglomerates by stirring the agglomerates at a low speed using an agitator, pan-disk or tumbler, after the agglomerating step (size enlargement step); passing water with the enlarged sludge-coal-oil agglomerates and unagglomerated inorganic materials through a sieve having 48 mesh or less to selectively separate the enlarged sludge-coal-oil agglomerates (screening step); and spray-washing and dewatering the enlarged sludged-coal-oil agglomerates after they are selectively separated from the unagglomerated inorganic materials.