DEWATERING OF DREDGED MATERIALS BY EVAPORATION.

DURING RECENT YEARS MANY OF THE BOTTOM SEDIMENTS DREDGED FROM THE HARBOURS AND CHANNELS LOCATED NEAR HEAVILY POPULATED INDUSTRIAL AREAS OF THE UNITED STATES HAVE BEEN JUDGED POLLUTED BY THE ENVIRONMENTAL PROTECTION AGENCY.AS A CONSEQUENCE, OPEN WATER DISPOSAL OF THESE MATERIALS IS SEVERELY RESTRICTED, AND THEY ARE OFTEN PLACED WITHIN DIKED CONTAINMENT AREAS.HOWEVER, SINCE SUCH DREDGINGS USUALLY HAVE A HIGH WATER CONTENT AND CONTAIN SUBSTANTIAL AMOUNTS OF CLAY-LIKE AND/OR ORGANIC MATERIALS, THE EFFECTIVENESS OF THE ASSOCIATED LANDFILL OPERATIONS AND THE UTILISATION OF THESE MATERIALS ARE STRONGLY AFFECTED BY THEIR DEWATERINO CHARACTERISTICS.EVAPORATION HAS BEEN IDENTIFIED AS AN EFFECTIVE AND ECONOMICAL MEANS FOR ACCOMPLISHING SUCH DEWATERING, AND THE QUANTITATIVE RESULTS OF SEVERAL FIELD AND LABORATORY STUDIES ARE EVALUATED HEREIN AND PLACED IN PERSPECTIVE.PURSUANT TO OBTAINING THE SOIL-WATER POTENTIAL OF SEVERAL TYPICAL DREDGINGS, THREE SERIES OF LABORATORY TESTS WERE CONDUCTED TO STUDY: (A) THE RATE OF WATER LOSS AND THE EFFECT OF MIXING, (B) THE INFLUENCE OF LAYER THICKNESS AND SURFACE AREA ON THE RATE OF WATER LOSS, AND (C) THE EFFECT OF LIME TREATMENT ON THE RA TE OF WATER LOSS.TWO SERIES OF FIELD EVAPORATION TESTS WERE PERFORMED TO INVESTIGATE THE EFFECTS OF SAMPLE THICKNESS, LIME-TREATMENT, AND DRAINAGE CONDITIONS ON THE EVAPORATIVE LOSSES OF WATER AND TIME DEPENDENT GAINS IN STRENGTH UNDER THE GIVEN CLIMATIC CONDITIONS.THE RESULTS OF THESE STUDIES ARE SUPPLEMENTED WITH THOSE OF SEVERAL OTHER STUDIES CONDUCTED BY OTHERS BUT NOT REPORTED IN THE LITERATURE.(A).